Re: Manger crossover
Pictures of Encore and the other Overkill speakers with MSW are posted here:
http://www.diyaudio.com/forums/showthread.php?postid=1794325#post1794325
(posts 5111 and 5112)
Overkill Audio said:
Pictures of Encore and the other Overkill speakers with MSW are posted here:
http://www.diyaudio.com/forums/showthread.php?postid=1794325#post1794325
(posts 5111 and 5112)
aj_newman said:
I suggest you to use Google sketchup to draw some plans. I see MTM good, but you have to isolate the MSW from woofers vibrations.
And that is a problem for my OB project. That and the relatively high XO point that the MSW would require.
I have much lower SPL requirements than Derek, so tbh I'm aiming for 150hz XO point and the use of just one woofer below that.
Computer-based XO with very steep phase-perfect 96db for the MSW and 48-64 for the woofer.
Of course the Manger would require a different woofer choice, than the Peerless SLS that I choose for a traditional cone driver.
aj_newman said:
100kb are way too small to give justice to Derek speakers, so I resized them a bit with Photoshop and used tinypic (my favourite image hosting, 100000 better than imageshack) to upload.
They look really good and I'm sure they sound better 🙂
aj_newman said:
Well, he never replied to my emails nor the last post on his forums, so I am disappointed with their CS. He gave me a throughout reply on audiocircle forum before Xmas, but after that, the nothing.
Also I think shipping to UK is much cheaper than to Italy, my quote was like 250$ (only shipping!)
I'm glad that they have been responsive with you, because I believe that the Lambda are among the best bass drivers and not really expensive over all.
I must have heard the 1st generation ICE and its bass sucked. I stayd clean off it since then. I have heard better bass from the nuforce (not entirely my cup of cake either btw) and today probably the best price/performance option is from the biggest tripath, the 3030, low distortion up to 100w.
Good luck with the amps anyway 🙂
Check Derek post in the Ariel thread. For OB, the MSW have too weak magnets. A reinforcement and/or some damping would be very beneficial.
Hello,
i think 91 dB 1 W 1m and ~ max. SPL 98 dB are possible.
It is a bipol double horn with membran movement
and bass horn mouth distance.
i think 91 dB 1 W 1m and ~ max. SPL 98 dB are possible.
It is a bipol double horn with membran movement
and bass horn mouth distance.
Telstar - thanks for the pics / tip on GoogleSketchUp. I'll have a play until the 'trial period' is up.
AE: In the event that you don't get a Forum response, I would email your question directly to the AE contact email. My email was initially responded to with: "Due to an overwhelming amount of email received, we are experiencing longer delays than we had hoped for in responding to email. We do read all emails and will respond to them as quickly as possible." Then an actual reply a few days later on.
Current (no pun) Nuforce amps have and order of magnitude more THD & noise @10W. http://www.nuforce.com/Product-Mono-Amplifier.htm
I have not idea if that means they sound different, but it may be that they are not as customised as some of the other ICEPower systems out there.
Tripath: I read about in 2006/2007? but don't remember much other than an even higher efficiency rating / or that the high efficiency made them idea for head units in cars?
MSW: I did manage to fry a pair of them when I cranked the volume too high - listening to them in a Stereo setup - large room. This time around, they are only going to be 2 metres from my ears - and so they should survive for a few years 🙂
Regards,
Tuckshop
AE: In the event that you don't get a Forum response, I would email your question directly to the AE contact email. My email was initially responded to with: "Due to an overwhelming amount of email received, we are experiencing longer delays than we had hoped for in responding to email. We do read all emails and will respond to them as quickly as possible." Then an actual reply a few days later on.
Current (no pun) Nuforce amps have and order of magnitude more THD & noise @10W. http://www.nuforce.com/Product-Mono-Amplifier.htm
I have not idea if that means they sound different, but it may be that they are not as customised as some of the other ICEPower systems out there.
Tripath: I read about in 2006/2007? but don't remember much other than an even higher efficiency rating / or that the high efficiency made them idea for head units in cars?
MSW: I did manage to fry a pair of them when I cranked the volume too high - listening to them in a Stereo setup - large room. This time around, they are only going to be 2 metres from my ears - and so they should survive for a few years 🙂
Regards,
Tuckshop
Manger crossover & stuff.
Hi Telstar and freinds,
Thanks for posting the Angel, Encore & Prey photos, glad you like them, the speakers were a labour of love!
Here are a few ideas and methods which I found very helpful in developing my systems.
A great way to use a pair of Manger drivers as development tools for your complete speaker system and evaluate source / amp / cable / racks etc is as follows.
(1) Run the Manger full range connected directly (with short runs of 0.8mm silver cable) your best power amp and the very highest quality passive volume control or pre amp from your best source and play your best recordings with material with NO BASS content!! Simple vocals / strings, and piano (not too much left hand here...!) and you can establish the ultimate midrange reference. It's important to use vocals and instruments which can be heard live with no electronic amplification or speakers i.e. electric guitar is never going be of reference. Great to listen to as music but not to establish a reference. Not too much volume, about 85dB is fine.
I highly recommend using an open baffle for this. Even if you are set on sealed, ported, horn, waveguide or whatever a simple open baffle reference point will allow you to establish a true reference point and set the midrange standard to aim for in whatever cabinet / crossover / electronics you develop.
(2) My best open baffle shape for the Manger is a triangular shape with 500mm to 700mm height, depending on the driver used to cover 100Hz to 300Hz / 400Hz range as this driver must be mounted close to the Manger driver on the same baffle. Separate baffles are not good as standing wave / resonance issues arise if two small OB are used.
The width at the base should be approx 450mm and about 250mm at the top. These dimensions are actually important and have to be matched to the low mid driver requirements.
I use the VPL U frame to give "weight and mass" to the low mid driver without any trace of "cuppy boomy" low mids that I hear with H frame or backless box low midrange designs.
When it comes to crossovers I have tried crazy passive (£1,200 worth or holy grail designer caps resistors and inductors) some very good analog active crossovers and several DSP active crossovers. General observations are:
(3) For low to medium SPL go for very simple passive crossover (6 or 12 dB slopes) with a two way configuration. Open baffle Manger, gentle crossover at around 200Hz into the Volt BM2500.4 in a simple sealed 45litre box with some clever internal damping is very hard to beat at any price. The two drivers are very close in sensitivity (within 0.8 dB) over the bands they cover in this design so you can forget resistors, Yeeha!
(4) At the other end of the scale if you can afford to spend £ 10K
Then a three way with a custom 18inch VPL U frame bass system from 25Hz to 120Hz, a 10inch Volt BM251.4 Pro driver in a oval wave guide running up to 400Hz and then the Manger in a shallow (125mm total depth) oval wave guide, all controlled by a battery powered DEQX (or Dolby Lake processor) is the way to go.
(5) My test baffle for the Volt / Manger is 650mm tall but I may use an AE TD 12M in place of the Volt, I havnt had a chance to test the AE driver yet so the baffle may be 700mm tall.
Thats it for now as I am going out to walk the dog and throw frisby with the kids!
All the best
Derek.
Hi Telstar and freinds,
Thanks for posting the Angel, Encore & Prey photos, glad you like them, the speakers were a labour of love!
Here are a few ideas and methods which I found very helpful in developing my systems.
A great way to use a pair of Manger drivers as development tools for your complete speaker system and evaluate source / amp / cable / racks etc is as follows.
(1) Run the Manger full range connected directly (with short runs of 0.8mm silver cable) your best power amp and the very highest quality passive volume control or pre amp from your best source and play your best recordings with material with NO BASS content!! Simple vocals / strings, and piano (not too much left hand here...!) and you can establish the ultimate midrange reference. It's important to use vocals and instruments which can be heard live with no electronic amplification or speakers i.e. electric guitar is never going be of reference. Great to listen to as music but not to establish a reference. Not too much volume, about 85dB is fine.
I highly recommend using an open baffle for this. Even if you are set on sealed, ported, horn, waveguide or whatever a simple open baffle reference point will allow you to establish a true reference point and set the midrange standard to aim for in whatever cabinet / crossover / electronics you develop.
(2) My best open baffle shape for the Manger is a triangular shape with 500mm to 700mm height, depending on the driver used to cover 100Hz to 300Hz / 400Hz range as this driver must be mounted close to the Manger driver on the same baffle. Separate baffles are not good as standing wave / resonance issues arise if two small OB are used.
The width at the base should be approx 450mm and about 250mm at the top. These dimensions are actually important and have to be matched to the low mid driver requirements.
I use the VPL U frame to give "weight and mass" to the low mid driver without any trace of "cuppy boomy" low mids that I hear with H frame or backless box low midrange designs.
When it comes to crossovers I have tried crazy passive (£1,200 worth or holy grail designer caps resistors and inductors) some very good analog active crossovers and several DSP active crossovers. General observations are:
(3) For low to medium SPL go for very simple passive crossover (6 or 12 dB slopes) with a two way configuration. Open baffle Manger, gentle crossover at around 200Hz into the Volt BM2500.4 in a simple sealed 45litre box with some clever internal damping is very hard to beat at any price. The two drivers are very close in sensitivity (within 0.8 dB) over the bands they cover in this design so you can forget resistors, Yeeha!
(4) At the other end of the scale if you can afford to spend £ 10K
Then a three way with a custom 18inch VPL U frame bass system from 25Hz to 120Hz, a 10inch Volt BM251.4 Pro driver in a oval wave guide running up to 400Hz and then the Manger in a shallow (125mm total depth) oval wave guide, all controlled by a battery powered DEQX (or Dolby Lake processor) is the way to go.
(5) My test baffle for the Volt / Manger is 650mm tall but I may use an AE TD 12M in place of the Volt, I havnt had a chance to test the AE driver yet so the baffle may be 700mm tall.
Thats it for now as I am going out to walk the dog and throw frisby with the kids!
All the best
Derek.
Derek,
Seem like we have the same taste in woofers. I'm using 4 Volt 2500.4 in my 'too heavy to lift up stairs' subs. Volt were driving me mad on late delivery when I was building them. A certain Richard Lord was using Volts resources to capacity to build modified BM2500 units.
I need to go away and digest your (and Telstars) posts. The one area that I haven't quite thought through is the baffle (assuming I use one) that the MSW will sit.
+) No baffle = 8" circular ring around manger will act like a another source.
+) Extended baffle - right into my array of 15" units - may self resonate
+) Star shaped, or hourglass (Skinny in the middle) may also break up HF reflections from a single source.
My other thoughts are that a Wave guide on the front and back of the manger could be used to ensure the 15" bass units are not 'seen' by the emerging wavefront.
Then I stared wondering if I could great a foam (or aperiodic) waveguide to only effect the HF output of the MSW, and now the LF.
Regards
Seem like we have the same taste in woofers. I'm using 4 Volt 2500.4 in my 'too heavy to lift up stairs' subs. Volt were driving me mad on late delivery when I was building them. A certain Richard Lord was using Volts resources to capacity to build modified BM2500 units.
I need to go away and digest your (and Telstars) posts. The one area that I haven't quite thought through is the baffle (assuming I use one) that the MSW will sit.
+) No baffle = 8" circular ring around manger will act like a another source.
+) Extended baffle - right into my array of 15" units - may self resonate
+) Star shaped, or hourglass (Skinny in the middle) may also break up HF reflections from a single source.
My other thoughts are that a Wave guide on the front and back of the manger could be used to ensure the 15" bass units are not 'seen' by the emerging wavefront.
Then I stared wondering if I could great a foam (or aperiodic) waveguide to only effect the HF output of the MSW, and now the LF.
Regards
Attachments
Telstar,
Those Tripath units look amazing value for money.
In post 11 of:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=134747&perpage=25&pagenumber=1
Have similar ultimate THD levels as the SX-1000:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=134747&perpage=25&pagenumber=1
The main difference (beside cost!), is the point at which distortion rockets ups.
For my purpose, I'm looking for 500W into 5.4 ohms (ie 2 AEs units in series) = (27db Gain). With 3 x SX-1000 driving 3 pairs of drivers, I am hoping there will be sufficient headroom to equalise the units without going over 0.05% THD (arbibrary point again).
For the Mangers, I am only need 150W. Which should improve the SX-1000's performance. (I'll wheel in a Bryston if needed).
Regards
Those Tripath units look amazing value for money.
In post 11 of:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=134747&perpage=25&pagenumber=1
Have similar ultimate THD levels as the SX-1000:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=134747&perpage=25&pagenumber=1
The main difference (beside cost!), is the point at which distortion rockets ups.
For my purpose, I'm looking for 500W into 5.4 ohms (ie 2 AEs units in series) = (27db Gain). With 3 x SX-1000 driving 3 pairs of drivers, I am hoping there will be sufficient headroom to equalise the units without going over 0.05% THD (arbibrary point again).
For the Mangers, I am only need 150W. Which should improve the SX-1000's performance. (I'll wheel in a Bryston if needed).
Regards
Re: Manger crossover & stuff.
Hello Derek,
Thanks for the reply.
This is already what I plan to do more or less... for the definitive setup 😉
My project idea is of an OB fullrange + bass support.
Except the XO thing, that for the Manger a highpass IS needed .
Excuse me but you mean trapezoid, or triangular?
VPL?
Is this the acrylic baffle of the Angels?
This is the option I wanted to go for a "standard" FR driver in OB.
But I'm afraid that is not enough protection for the MSW. SPL goal is pretty low (95db peaks).
The alternative for me is computer based XO, with a very steep highpass filter for the MSW, and also for the woofers. But it's not sure if i can have double input, so I appreciate that i could still be able to a simple passive filter for moderate playback levels.
No sealed boxes for me. Dipole or cardioid bass. I have room modes to kill in the 60-110hz range. This is the reason why, I will experiment without bass/midbass at all.
I will biamp, so woofers sensitivity is not an issue. What i find important with the MSW is the "cleanliness" of the woofers.
TBH, I'm looking for cheaper, and european alternatives to the Volts (havent got a quote yet) in 10 or 12" size max.
I cannot 😉
Hello Derek,
Thanks for the reply.
Overkill Audio said:
This is already what I plan to do more or less... for the definitive setup 😉
My project idea is of an OB fullrange + bass support.
Except the XO thing, that for the Manger a highpass IS needed .
Excuse me but you mean trapezoid, or triangular?
VPL?
Is this the acrylic baffle of the Angels?
This is the option I wanted to go for a "standard" FR driver in OB.
But I'm afraid that is not enough protection for the MSW. SPL goal is pretty low (95db peaks).
The alternative for me is computer based XO, with a very steep highpass filter for the MSW, and also for the woofers. But it's not sure if i can have double input, so I appreciate that i could still be able to a simple passive filter for moderate playback levels.
No sealed boxes for me. Dipole or cardioid bass. I have room modes to kill in the 60-110hz range. This is the reason why, I will experiment without bass/midbass at all.
I will biamp, so woofers sensitivity is not an issue. What i find important with the MSW is the "cleanliness" of the woofers.
TBH, I'm looking for cheaper, and european alternatives to the Volts (havent got a quote yet) in 10 or 12" size max.
I cannot 😉
Manger bass matching
Hi Telstar,
Your project sounds like a very sweet combination of ideas.
My thoughts are as follows:
(1) OOpps! You are correct Trapezoid not triangular. I will take some photos of my current test cabinets (un finished and ugly but sound great!) and send them to you.
(2) My VPL U frame idea is the shape shown in the Acrylic "Angel" cabinets. You can adapt the shape to suite almost any bass or bass / mid driver and you can make the cabinet wings from any material from ultra light weight open cell material ( I favour low mass big time ) all the way through to very dense bitumen/ lead /bitumen plus hard board composite.
(3) I explain a bit more about the VPL concept in a recent post on the "Beyond the Ariel "post. Basically its a zero cost way to get rid of 80% (approx) of the unwanted resonance that is inherent in the U frame ( even worse in H frame) but you still retain almost all of the bass and all of the low midrange extension.
As you can see from the photos you take a "shark bite" out each side baffle and this instantly gives you a "Variable Path Lengh" (VPL) cancelation which (a) avoids the 150 Hz to 200Hz spike with 12 to 18 inch U or H frame and corresponding cuppy boomy sound quality. (b) lowers the mass of the pannel which always helps.
(4) The VPL shape can be adapted to suite almost any driver, depending on the frequencies covered, the crossover slope, the bandwith of the driver, the Fs etc.
(5) VPL is effectivly a "one shot" mechanical filter wihich can be custom tuned just like an electrical filter.
It is best used in conjunction with DSP active crossovers to then fine tune out any residual peaks (especially in usuful in the 200Hz to 400Hz band)
(6) I would imagine John K could use this to great effect with his active analog crossovers / filters.
(7) I have always had great results with the Manger used above 300 Hz. Sometimes (parties or Hi Fi shows!) I go to a 400Hz crossover (always 48 to 60dB linear phase crossover) where you can honestly pump in 200 watts full power from a high current solid state power amp ( Dave Belles of Power Modules makes some good ones) and the dynamics are astonishing!
"Power sponges", sorry, resistors, caps & inductors get hot and suck up energy, and then of course release some of that energy out of phase and smear the time coherence of the Manger (or any driver) so when you get rid of them and use a top quality DSP everything just gets so much more real and dynamic.
(8) My original Volt 2500.4 in a sealed box plus Open Baffle VPL Manger with a simple passive crossover at 200Hz to 300Hz is the very best sound I have ever heard from any passive speaker. It is compromised by the passive xover and can not hit SPL's above 95dBwithout distorting the Manger. But for under £2,000 fully finished it is simply awsome and with full respect to Daniela and Joseph Manger, both of whom I know personally, this design simply outperforms any passive Zero box or Swing.
(9) By spending a bit more (£1,000 to £2,000) you can replace the passive crossovers with a second hand DEQX or other good DSP crossver. This is a major sonic upgrade and opens up the the design possibilities. You can then add one or two subwoofers (sealed or open baffle) and run the Volt in a VPL open baffle (see my "Finale" photograph) which is absolutly amazing.
(10) The passive Volt / Manger set up is just stage one in a modular upgrade path that avoids too many redundand drivers / cabinets.
(11) AE drivers from America look great, Volt are great, Bemya are the best value for money ever! Pablo from Beyma is a great designer and very helpfull with technical questions, but you do need to be ordering 50 drivers or more...! PHL from France are very close to Volt performance and lower cost and much faster delivery. David at Volt is slow, slow, slow! But his drivers are fast fast fast...! Try PHL they really are top class.
(12) With all bass and bass / mid drivers to match the speed of the Manger its all about ratio's of driver spec. I will go into this in more detail in another post as this one is already too long, but briefly, the critical Mms to Bl ratio, the voice coil to SD ratio, voice coil cooling, low inductance over the frequency band you are running the driver in and the most important is the true driver efficiency.
Got to go now, hope this all helps and more to follow later this week.
Cheers
Derek.
Hi Telstar,
Your project sounds like a very sweet combination of ideas.
My thoughts are as follows:
(1) OOpps! You are correct Trapezoid not triangular. I will take some photos of my current test cabinets (un finished and ugly but sound great!) and send them to you.
(2) My VPL U frame idea is the shape shown in the Acrylic "Angel" cabinets. You can adapt the shape to suite almost any bass or bass / mid driver and you can make the cabinet wings from any material from ultra light weight open cell material ( I favour low mass big time ) all the way through to very dense bitumen/ lead /bitumen plus hard board composite.
(3) I explain a bit more about the VPL concept in a recent post on the "Beyond the Ariel "post. Basically its a zero cost way to get rid of 80% (approx) of the unwanted resonance that is inherent in the U frame ( even worse in H frame) but you still retain almost all of the bass and all of the low midrange extension.
As you can see from the photos you take a "shark bite" out each side baffle and this instantly gives you a "Variable Path Lengh" (VPL) cancelation which (a) avoids the 150 Hz to 200Hz spike with 12 to 18 inch U or H frame and corresponding cuppy boomy sound quality. (b) lowers the mass of the pannel which always helps.
(4) The VPL shape can be adapted to suite almost any driver, depending on the frequencies covered, the crossover slope, the bandwith of the driver, the Fs etc.
(5) VPL is effectivly a "one shot" mechanical filter wihich can be custom tuned just like an electrical filter.
It is best used in conjunction with DSP active crossovers to then fine tune out any residual peaks (especially in usuful in the 200Hz to 400Hz band)
(6) I would imagine John K could use this to great effect with his active analog crossovers / filters.
(7) I have always had great results with the Manger used above 300 Hz. Sometimes (parties or Hi Fi shows!) I go to a 400Hz crossover (always 48 to 60dB linear phase crossover) where you can honestly pump in 200 watts full power from a high current solid state power amp ( Dave Belles of Power Modules makes some good ones) and the dynamics are astonishing!
"Power sponges", sorry, resistors, caps & inductors get hot and suck up energy, and then of course release some of that energy out of phase and smear the time coherence of the Manger (or any driver) so when you get rid of them and use a top quality DSP everything just gets so much more real and dynamic.
(8) My original Volt 2500.4 in a sealed box plus Open Baffle VPL Manger with a simple passive crossover at 200Hz to 300Hz is the very best sound I have ever heard from any passive speaker. It is compromised by the passive xover and can not hit SPL's above 95dBwithout distorting the Manger. But for under £2,000 fully finished it is simply awsome and with full respect to Daniela and Joseph Manger, both of whom I know personally, this design simply outperforms any passive Zero box or Swing.
(9) By spending a bit more (£1,000 to £2,000) you can replace the passive crossovers with a second hand DEQX or other good DSP crossver. This is a major sonic upgrade and opens up the the design possibilities. You can then add one or two subwoofers (sealed or open baffle) and run the Volt in a VPL open baffle (see my "Finale" photograph) which is absolutly amazing.
(10) The passive Volt / Manger set up is just stage one in a modular upgrade path that avoids too many redundand drivers / cabinets.
(11) AE drivers from America look great, Volt are great, Bemya are the best value for money ever! Pablo from Beyma is a great designer and very helpfull with technical questions, but you do need to be ordering 50 drivers or more...! PHL from France are very close to Volt performance and lower cost and much faster delivery. David at Volt is slow, slow, slow! But his drivers are fast fast fast...! Try PHL they really are top class.
(12) With all bass and bass / mid drivers to match the speed of the Manger its all about ratio's of driver spec. I will go into this in more detail in another post as this one is already too long, but briefly, the critical Mms to Bl ratio, the voice coil to SD ratio, voice coil cooling, low inductance over the frequency band you are running the driver in and the most important is the true driver efficiency.
Got to go now, hope this all helps and more to follow later this week.
Cheers
Derek.
Re: Manger bass matching
Hi Telstar,
Your project sounds like a very sweet combination of ideas.
Thanks! This will be my second speaker project. I'm currently finishing one based on the Hemp FR8C, w/o crossover. It will help to evaluate OB in my room and to play with dampening.
My thoughts are as follows:
(1) OOpps! You are correct Trapezoid not triangular. I will take some photos of my current test cabinets (un finished and ugly but sound great!) and send them to you.
Ok, you can email me when you have time 🙂
Can you just repeat base width, top width and height?
(2) My VPL U frame idea is the shape shown in the Acrylic "Angel" cabinets. You can adapt the shape to suite almost any bass or bass / mid driver and you can make the cabinet wings from any material from ultra light weight open cell material ( I favour low mass big time ) all the way through to very dense bitumen/ lead /bitumen plus hard board composite.
I'm a wood person, but for the wings i like the transparency of plexiglass, it looks less imposing (= better WAF)
(3) I explain a bit more about the VPL concept in a recent post on the "Beyond the Ariel "post. Basically its a zero cost way to get rid of 80% (approx) of the unwanted resonance that is inherent in the U frame ( even worse in H frame) but you still retain almost all of the bass and all of the low midrange extension.
As you can see from the photos you take a "shark bite" out each side baffle and this instantly gives you a "Variable Path Lengh" (VPL) cancelation which (a) avoids the 150 Hz to 200Hz spike with 12 to 18 inch U or H frame and corresponding cuppy boomy sound quality. (b) lowers the mass of the pannel which always helps.
(4) The VPL shape can be adapted to suite almost any driver, depending on the frequencies covered, the crossover slope, the bandwith of the driver, the Fs etc.
Very, very interesting. And smart 🙂
I'll treasure this info.
(cut)
(7) I have always had great results with the Manger used above 300 Hz. Sometimes (parties or Hi Fi shows!) I go to a 400Hz crossover (always 48 to 60dB linear phase crossover) where you can honestly pump in 200 watts full power from a high current solid state power amp ( Dave Belles of Power Modules makes some good ones) and the dynamics are astonishing!
"Power sponges", sorry, resistors, caps & inductors get hot and suck up energy, and then of course release some of that energy out of phase and smear the time coherence of the Manger (or any driver) so when you get rid of them and use a top quality DSP everything just gets so much more real and dynamic.
I agree. I have only my 15W F3 too feed the Manger (spl goal of 90, no big volumes here as u can see). Still cant figure out on paper where ths XO should be, but I think in the 200hz area, and hoping less.
(8) My original Volt 2500.4 in a sealed box plus Open Baffle VPL Manger with a simple passive crossover at 200Hz to 300Hz is the very best sound I have ever heard from any passive speaker. It is compromised by the passive xover and can not hit SPL's above 95dBwithout distorting the Manger. But for under £2,000 fully finished it is simply awsome and with full respect to Daniela and Joseph Manger, both of whom I know personally, this design simply outperforms any passive Zero box or Swing.
Very sweet. I'll go to listen to the Swings soon.
But I have decided to go active for the bass long time ago. So I dont have sensitivity to match and I can choose the right woofer(s) with more freedom. 🙂
(11) AE drivers from America look great, Volt are great, Bemya are the best value for money ever! Pablo from Beyma is a great designer and very helpfull with technical questions, but you do need to be ordering 50 drivers or more...! PHL from France are very close to Volt performance and lower cost and much faster delivery. David at Volt is slow, slow, slow! But his drivers are fast fast fast...! Try PHL they really are top class.
I had considered a Beyma driver in the past, but later for various reasons I ended choosing a Peerless SLS 12" (which I dont think it's a good match for the MSW, too high Le and Xmax). I will check the entire Beyma line again and see if I can come for an alternative to Volts.
Anyway at about £250 a pop they are not cheap but not extremely expensive either, esp if i can manage to use only one driver per side.
The good thing about the Volts is that they have 10" with very good performance in the low freqs. I have space constraints, so the narrower the baffle, the better.
The one that I think looks the best to go from 30 to approx 200hz is the Volt BM2500.4
DOH! I ust noticed that you used it too in sealed box. So, you approve the use of this driver, right?
I want to avoid overseas shipping and customs, so i'll stay in europe for sure.
PHL, you mean PHY-HP?
(12) With all bass and bass / mid drivers to match the speed of the Manger its all about ratio's of driver spec. I will go into this in more detail in another post as this one is already too long, but briefly, the critical Mms to Bl ratio, the voice coil to SD ratio, voice coil cooling, low inductance over the frequency band you are running the driver in and the most important is the true driver efficiency.
Yes, please, explain which parameters to look for. So far, i'm focusing on Fs of around 30-35hz, low Le (under 1mh) and not excessive Xmax.
I dont care too much about efficiency,because it will be separately powered with volume adjustment to match (by ears) the MSW.
Hi Telstar,
Your project sounds like a very sweet combination of ideas.
Thanks! This will be my second speaker project. I'm currently finishing one based on the Hemp FR8C, w/o crossover. It will help to evaluate OB in my room and to play with dampening.
My thoughts are as follows:
(1) OOpps! You are correct Trapezoid not triangular. I will take some photos of my current test cabinets (un finished and ugly but sound great!) and send them to you.
Ok, you can email me when you have time 🙂
Can you just repeat base width, top width and height?
(2) My VPL U frame idea is the shape shown in the Acrylic "Angel" cabinets. You can adapt the shape to suite almost any bass or bass / mid driver and you can make the cabinet wings from any material from ultra light weight open cell material ( I favour low mass big time ) all the way through to very dense bitumen/ lead /bitumen plus hard board composite.
I'm a wood person, but for the wings i like the transparency of plexiglass, it looks less imposing (= better WAF)
(3) I explain a bit more about the VPL concept in a recent post on the "Beyond the Ariel "post. Basically its a zero cost way to get rid of 80% (approx) of the unwanted resonance that is inherent in the U frame ( even worse in H frame) but you still retain almost all of the bass and all of the low midrange extension.
As you can see from the photos you take a "shark bite" out each side baffle and this instantly gives you a "Variable Path Lengh" (VPL) cancelation which (a) avoids the 150 Hz to 200Hz spike with 12 to 18 inch U or H frame and corresponding cuppy boomy sound quality. (b) lowers the mass of the pannel which always helps.
(4) The VPL shape can be adapted to suite almost any driver, depending on the frequencies covered, the crossover slope, the bandwith of the driver, the Fs etc.
Very, very interesting. And smart 🙂
I'll treasure this info.
(cut)
(7) I have always had great results with the Manger used above 300 Hz. Sometimes (parties or Hi Fi shows!) I go to a 400Hz crossover (always 48 to 60dB linear phase crossover) where you can honestly pump in 200 watts full power from a high current solid state power amp ( Dave Belles of Power Modules makes some good ones) and the dynamics are astonishing!
"Power sponges", sorry, resistors, caps & inductors get hot and suck up energy, and then of course release some of that energy out of phase and smear the time coherence of the Manger (or any driver) so when you get rid of them and use a top quality DSP everything just gets so much more real and dynamic.
I agree. I have only my 15W F3 too feed the Manger (spl goal of 90, no big volumes here as u can see). Still cant figure out on paper where ths XO should be, but I think in the 200hz area, and hoping less.
(8) My original Volt 2500.4 in a sealed box plus Open Baffle VPL Manger with a simple passive crossover at 200Hz to 300Hz is the very best sound I have ever heard from any passive speaker. It is compromised by the passive xover and can not hit SPL's above 95dBwithout distorting the Manger. But for under £2,000 fully finished it is simply awsome and with full respect to Daniela and Joseph Manger, both of whom I know personally, this design simply outperforms any passive Zero box or Swing.
Very sweet. I'll go to listen to the Swings soon.
But I have decided to go active for the bass long time ago. So I dont have sensitivity to match and I can choose the right woofer(s) with more freedom. 🙂
(11) AE drivers from America look great, Volt are great, Bemya are the best value for money ever! Pablo from Beyma is a great designer and very helpfull with technical questions, but you do need to be ordering 50 drivers or more...! PHL from France are very close to Volt performance and lower cost and much faster delivery. David at Volt is slow, slow, slow! But his drivers are fast fast fast...! Try PHL they really are top class.
I had considered a Beyma driver in the past, but later for various reasons I ended choosing a Peerless SLS 12" (which I dont think it's a good match for the MSW, too high Le and Xmax). I will check the entire Beyma line again and see if I can come for an alternative to Volts.
Anyway at about £250 a pop they are not cheap but not extremely expensive either, esp if i can manage to use only one driver per side.
The good thing about the Volts is that they have 10" with very good performance in the low freqs. I have space constraints, so the narrower the baffle, the better.
The one that I think looks the best to go from 30 to approx 200hz is the Volt BM2500.4
DOH! I ust noticed that you used it too in sealed box. So, you approve the use of this driver, right?
I want to avoid overseas shipping and customs, so i'll stay in europe for sure.
PHL, you mean PHY-HP?
(12) With all bass and bass / mid drivers to match the speed of the Manger its all about ratio's of driver spec. I will go into this in more detail in another post as this one is already too long, but briefly, the critical Mms to Bl ratio, the voice coil to SD ratio, voice coil cooling, low inductance over the frequency band you are running the driver in and the most important is the true driver efficiency.
Yes, please, explain which parameters to look for. So far, i'm focusing on Fs of around 30-35hz, low Le (under 1mh) and not excessive Xmax.
I dont care too much about efficiency,because it will be separately powered with volume adjustment to match (by ears) the MSW.
Bass / lo mid for Manger
Hi Telstar,
I have never tried the PHY-HP drivers, way tooo expensive for conventional small pistonic driver.
www.phlaudio.com is the website for some good alternatives to Volt.
The cabinet dimensions for my ( work in progress!) latest VPL U frame 3 way active (using battery powered DEQX) system are:
Head unit (Manger plus 10 inch Volt 2500.4 or Volt 251.4 low mid driver) :
Width at base 450mm,
Width at top 250mm,
Height 600mm.
10mm thick Sorbothane sheet separates this head unit from the:
VPL U frame bass cabinet (15 inch Beyma SM115K or 18 inch custom driver)
Width at base 600mm
Width at top 450mm
Height 650mm.
The depth of the side cheeks varies depending on frequency band covered and drivers used. When I have done a bit more testing I will confirm the dimensions and curvature required.
I am very tempted to try an Acoustic Elegance TD 12 M or even a TD 15 M(!) in place of the 10 inch Volt driver.
Has anyone got direct experience of comparing the Volt with the AE drivers, I would be very interested in your views!
On driver specs to best suit a VPL U frame there are no hard and fast rules as all the parameters ultimatley have to blend together in the end result, but here are some "golden ratios" & pointers:
(1) Mms to Bl ratio is key. i.e. Volt 2500.4 : 48g Mms / 15.5 Bl = 3.09. This figure of 3.09 is very good for my VPL application. The lower the figure the faster the cone will be able to start / stop, all other things being equal. An ultra fast 10 inch driver is the Precision Devices PDN 10MH25 i.e. 37.2g Mms / 21.8 Bl = 1.7 ! Great mids but it does not go low enough.
Contrast that with a Scan Speak Revelator 10 inch bass driver Mms 51g / Bl of 8.3 = 6.1 ! This driver will give lots of bass output down to its 18Hz Fs but its all muddy & confused as the heavy cone and loose suspension oscillate over a long time period with a weak Bl factor unable to control the puny 50mm voice coil! Ahem ....you get the picture!
The Volt is a lovely technical compromise and beautifully engineered piece of kit.
Its sister driver the more efficient Volt BM251.4 is a lower Mms version with a great 28g Mms / 11.9 Bl = 2.35. A great figure for a 10 inch driver. The down side of this driver is a small 50mm voice coil so real world dynamics are going to give it trouble. The stiffer suspension also raise the Fs too high so it struggles in a VPL U frame to get down to 100Hz. It sounds a wee bit lean in the 100Hz to 200Hz band, but boy is it fast!
Lower Fs = longer oscillation.
Higher Fs shorter oscillation.
All coned drivers are just a mass on a spring, (cone with a suspension & surround) so we can tweak high Bl, low Mms and suspension to best suit our purpose.
(2) Sd to Voice coil diameter ratio. Using the Volt 2500.4 example . Sd 299 / 75mm = 3.98. This is very good, not many off the shelf 10 inch drivers have voice coils bigger than 75mm so this is hard to beat at this Sd.
Strive to use the largest Sd driver you can whilst maintain "fast" Mms to Bl ratio and covering the full frequency band you require. The bigger the voice coil the better!
Maximum cooling for voice coil is vital, single layer best, double layer not good, never use a 4 layer voice coil.
Alloy former best, paper / natural fibre ok, Nomex, Kapton etc not good but less important than voice coil size, usually!
(3) Qts, low is great! Ignore the old rule of thumb Qts above 0.5, you will get far superior deep, fast, textured bass from low Qts drivers. High Qts is only required in traditional open baffle with passive crossovers. High Qts is lots of cone resonance spreading out over a broad band of frequencies, very bad!
(4) Low voice coil inductance is very important. Lower inductance = lower energy storage & lower energy (time) smearing. This is why I am so drawn to try the AE drivers. Not because we need good high frequency extension (I only run up to 300Hz or 400Hz ) and then the Manger takes over.
(5) Bl. The higher the better.
(6) Mms. The lower the better. The ratio of voice coil mass to cone mass is important i.e. its good to increase a 30g Mms to
35g Mms if you are doing so by increasing a 50mm voice coil to a 75 mm voice coil, but bad if you are just adding 5g of cone dampening gunge.
** Remember increasing voice coil diameter is adding to the motor strength, increasing cone mass is adding to the "dead weight" the motor is trying to drive! **
(7) Linen / pleated cloth surrounds are great. Heavy rubber is bad!
(8) Its important that the voice coil stays accurately aligned and controlled in the magnetic gap. Spider and surround are the dominant factors here, but an overkill (!) Bl factor helps. Remember Qts is not an issue in my application.
(9) Overall efficiency within the frequency band you are covering with the driver. Beware, most manufacturers quote an "average sensitivity" over a carefully chosen section of the drivers range. Always check the graphs!
(10) Ultra high build quality with very tight spec tolerance is good! Obvious statement but worth repeating that a drivers long term performance depends on staying aligned and glued together. Made in "El cheapo" is a false economy!
(11) Paper cones always seem to sound best. You can use metal cones (Seas) if you keep them well below their maximum recommended high frequency limit, but I now only spec paper.
(12) Magnet type. I am undecided on this one.
(13) Profile of cone. Shallow cone shape is much better. Exaggerated cone profiles are more rigid but exhibit a range of sonic nasties.
There is also the much neglected area of driver cone aerodynamics. This subject deserves a whole post on its own so I will keep my powder dry on this one!
(14) Cast alloy frames good, stamped steel bad. The more open backed the better. i.e. grasshopper legs like AE is best.
As you can tell from the above driver design / selection is a real tail chasing set of compromises, and it can drive you crazy at times!
Hope some of this helps, it has taken me 20 years to conclude the above and many people disagree with me on paper, but not after they have a listen to my system....!
Have fun and all the best.
Derek.
Hi Telstar,
I have never tried the PHY-HP drivers, way tooo expensive for conventional small pistonic driver.
www.phlaudio.com is the website for some good alternatives to Volt.
The cabinet dimensions for my ( work in progress!) latest VPL U frame 3 way active (using battery powered DEQX) system are:
Head unit (Manger plus 10 inch Volt 2500.4 or Volt 251.4 low mid driver) :
Width at base 450mm,
Width at top 250mm,
Height 600mm.
10mm thick Sorbothane sheet separates this head unit from the:
VPL U frame bass cabinet (15 inch Beyma SM115K or 18 inch custom driver)
Width at base 600mm
Width at top 450mm
Height 650mm.
The depth of the side cheeks varies depending on frequency band covered and drivers used. When I have done a bit more testing I will confirm the dimensions and curvature required.
I am very tempted to try an Acoustic Elegance TD 12 M or even a TD 15 M(!) in place of the 10 inch Volt driver.
Has anyone got direct experience of comparing the Volt with the AE drivers, I would be very interested in your views!
On driver specs to best suit a VPL U frame there are no hard and fast rules as all the parameters ultimatley have to blend together in the end result, but here are some "golden ratios" & pointers:
(1) Mms to Bl ratio is key. i.e. Volt 2500.4 : 48g Mms / 15.5 Bl = 3.09. This figure of 3.09 is very good for my VPL application. The lower the figure the faster the cone will be able to start / stop, all other things being equal. An ultra fast 10 inch driver is the Precision Devices PDN 10MH25 i.e. 37.2g Mms / 21.8 Bl = 1.7 ! Great mids but it does not go low enough.
Contrast that with a Scan Speak Revelator 10 inch bass driver Mms 51g / Bl of 8.3 = 6.1 ! This driver will give lots of bass output down to its 18Hz Fs but its all muddy & confused as the heavy cone and loose suspension oscillate over a long time period with a weak Bl factor unable to control the puny 50mm voice coil! Ahem ....you get the picture!
The Volt is a lovely technical compromise and beautifully engineered piece of kit.
Its sister driver the more efficient Volt BM251.4 is a lower Mms version with a great 28g Mms / 11.9 Bl = 2.35. A great figure for a 10 inch driver. The down side of this driver is a small 50mm voice coil so real world dynamics are going to give it trouble. The stiffer suspension also raise the Fs too high so it struggles in a VPL U frame to get down to 100Hz. It sounds a wee bit lean in the 100Hz to 200Hz band, but boy is it fast!
Lower Fs = longer oscillation.
Higher Fs shorter oscillation.
All coned drivers are just a mass on a spring, (cone with a suspension & surround) so we can tweak high Bl, low Mms and suspension to best suit our purpose.
(2) Sd to Voice coil diameter ratio. Using the Volt 2500.4 example . Sd 299 / 75mm = 3.98. This is very good, not many off the shelf 10 inch drivers have voice coils bigger than 75mm so this is hard to beat at this Sd.
Strive to use the largest Sd driver you can whilst maintain "fast" Mms to Bl ratio and covering the full frequency band you require. The bigger the voice coil the better!
Maximum cooling for voice coil is vital, single layer best, double layer not good, never use a 4 layer voice coil.
Alloy former best, paper / natural fibre ok, Nomex, Kapton etc not good but less important than voice coil size, usually!
(3) Qts, low is great! Ignore the old rule of thumb Qts above 0.5, you will get far superior deep, fast, textured bass from low Qts drivers. High Qts is only required in traditional open baffle with passive crossovers. High Qts is lots of cone resonance spreading out over a broad band of frequencies, very bad!
(4) Low voice coil inductance is very important. Lower inductance = lower energy storage & lower energy (time) smearing. This is why I am so drawn to try the AE drivers. Not because we need good high frequency extension (I only run up to 300Hz or 400Hz ) and then the Manger takes over.
(5) Bl. The higher the better.
(6) Mms. The lower the better. The ratio of voice coil mass to cone mass is important i.e. its good to increase a 30g Mms to
35g Mms if you are doing so by increasing a 50mm voice coil to a 75 mm voice coil, but bad if you are just adding 5g of cone dampening gunge.
** Remember increasing voice coil diameter is adding to the motor strength, increasing cone mass is adding to the "dead weight" the motor is trying to drive! **
(7) Linen / pleated cloth surrounds are great. Heavy rubber is bad!
(8) Its important that the voice coil stays accurately aligned and controlled in the magnetic gap. Spider and surround are the dominant factors here, but an overkill (!) Bl factor helps. Remember Qts is not an issue in my application.
(9) Overall efficiency within the frequency band you are covering with the driver. Beware, most manufacturers quote an "average sensitivity" over a carefully chosen section of the drivers range. Always check the graphs!
(10) Ultra high build quality with very tight spec tolerance is good! Obvious statement but worth repeating that a drivers long term performance depends on staying aligned and glued together. Made in "El cheapo" is a false economy!
(11) Paper cones always seem to sound best. You can use metal cones (Seas) if you keep them well below their maximum recommended high frequency limit, but I now only spec paper.
(12) Magnet type. I am undecided on this one.
(13) Profile of cone. Shallow cone shape is much better. Exaggerated cone profiles are more rigid but exhibit a range of sonic nasties.
There is also the much neglected area of driver cone aerodynamics. This subject deserves a whole post on its own so I will keep my powder dry on this one!
(14) Cast alloy frames good, stamped steel bad. The more open backed the better. i.e. grasshopper legs like AE is best.
As you can tell from the above driver design / selection is a real tail chasing set of compromises, and it can drive you crazy at times!
Hope some of this helps, it has taken me 20 years to conclude the above and many people disagree with me on paper, but not after they have a listen to my system....!
Have fun and all the best.
Derek.
Original question!
Sorry Telstar I forgot to answer your original question!
Try the Beyma SM 115K crossed over at any point between 150Hz and 400Hz.
This is a great two way system in a VPL U frame, really great!
If you crossover at 200Hz using 48dB per octave linear phase filters and use the latest 96Khz software and matching Firmware you will get great results and high resolution measurements (borrow an Earthworks mic if yo
You can have your cake and eat it big time with the Beyma 15 SM 115 K driver crossing over to the Manger at any point you want (variable at the touch of a button with the DEQX) between 120Hz all the way u have the Behringer!).
You can use a one piece trapezoid baffle with VPL U frame wings and top.
Driver placement. I like the Manger centre to be at least 1 meter above floor height, as I like singers to sound like they are standing up!
The Beyma (or any low frequency driver) will benefit from floor renforcement (approx 3dB) if you place the driver within 50mm or so of the floor.
But even at a low crossover point (200Hz) its good to keep the drivers close together to avoid the "spread of vocals" and low mid harmonics being stretched out between two drivers spaced toofar apart.
This is not a big problem, I only mention it so that you are aware that I have not resolved the issue with this driver combination.
In my two way Encore (using the now discontinued Beyma 12LX60) I raised the 12 inch Bass driver up to the top of the 800mm tall cabinet but it was crossed over at 300Hz to 400Hz.
Using the Beyma 15 K in a one peice trapezoid baffle go for 560mm to 600mm width at the base, 250mm to 300mm at the top. I' ll need to check the exact measurements for the wings and top. I will PM you in a few days with that info if you want to build the cabinets.
Cheers
Derek.
Sorry Telstar I forgot to answer your original question!
Try the Beyma SM 115K crossed over at any point between 150Hz and 400Hz.
This is a great two way system in a VPL U frame, really great!
If you crossover at 200Hz using 48dB per octave linear phase filters and use the latest 96Khz software and matching Firmware you will get great results and high resolution measurements (borrow an Earthworks mic if yo
You can have your cake and eat it big time with the Beyma 15 SM 115 K driver crossing over to the Manger at any point you want (variable at the touch of a button with the DEQX) between 120Hz all the way u have the Behringer!).
You can use a one piece trapezoid baffle with VPL U frame wings and top.
Driver placement. I like the Manger centre to be at least 1 meter above floor height, as I like singers to sound like they are standing up!
The Beyma (or any low frequency driver) will benefit from floor renforcement (approx 3dB) if you place the driver within 50mm or so of the floor.
But even at a low crossover point (200Hz) its good to keep the drivers close together to avoid the "spread of vocals" and low mid harmonics being stretched out between two drivers spaced toofar apart.
This is not a big problem, I only mention it so that you are aware that I have not resolved the issue with this driver combination.
In my two way Encore (using the now discontinued Beyma 12LX60) I raised the 12 inch Bass driver up to the top of the 800mm tall cabinet but it was crossed over at 300Hz to 400Hz.
Using the Beyma 15 K in a one peice trapezoid baffle go for 560mm to 600mm width at the base, 250mm to 300mm at the top. I' ll need to check the exact measurements for the wings and top. I will PM you in a few days with that info if you want to build the cabinets.
Cheers
Derek.
Re: Original question!
What do you think of the 12BR70 (for 30-200hz range)?
I could easily use a pair, they are extremely cheap, but the constructions and parameters seem good.
Beyma 12BR70
I'm looking at other models right now.
I have space issues and the max width is 45cm at the base, which excludes most 15"... and also your trapez baffles do not fit 🙁
Overkill Audio said:
What do you think of the 12BR70 (for 30-200hz range)?
I could easily use a pair, they are extremely cheap, but the constructions and parameters seem good.
Beyma 12BR70
I'm looking at other models right now.
I have space issues and the max width is 45cm at the base, which excludes most 15"... and also your trapez baffles do not fit 🙁
Beyma SM 112 N in two way Manger
Hi Telstar,
The Beyma SM 112/N is a great value for money product and will sound sweet with the Manger in a two way open baffle.
52g Mms / Bl of 17.2 = 3 which is very good for a 12 inch driver, it will be fast bass, i.e. textured, detailed and solid.
The compromises suit your design very well, as I understand your broad design remit is:
(1) High WAF / small cabinet.
(2) good dynamics but not the kind of high SPL AJ and I love!
(3) Future upgrade path avoiding redundant components.
The only slight technical compromises with this driver will be the medium / high Fs (for a 12 inch bass driver) will limit the usable low end extension in a VPL OB to around 40Hz.
Edit : You will need a baffle approx 50cm wide with VPL wings 550mm deep with the "shark bites" bringing the shallow point down to approx 24cm. The DEQX will tidy up any remaining peaks and can give you some 30Hz to 6oHz boost if required. But the Xmax is only 5.5mm so dont go crazy...!
The 38Hz "official" Fs is always plus or minus 5% to 10% in this price bracket for drivers. So you could be looking at anything from 35Hz to 41Hz real world Fs.
To compensate a little you can apply a few thin coats of cone damping material (good old water based PVA wood glue works very well for about £1.00 a tube! This will increase the Mms and therefore lower the Fs. Don't go crazy here but get some accurate scales and weigh out say 5g of PVA and apply this in multiple thin coats until each cone has its 5g applied.
This will drop the Fs by approx 4Hz (10%) getting you very close to your 30Hz target. If you have the patience you can spread the PVA over the back of the cone as well as the front.
Give the dust cap plenty of glue as its a very hard paper and needs some "calming down".
Be careful not get any PVA glue on the surround as this will stiffen it up and raise the Fs!!
It's actually very interesting to compare the SM 112 N with the Beyma SM 115 K, it has a Mms of 106g, a Bl of 20.5 so a ratio of 5.1 and its still great on vocals at cello at 200Hz.
Its Sd is 880 ( 60% more than the 550 of the SM 112N ) so its only having to move 40% as far with each compression / rarefaction compared to the 112 N.
Comparing the Mms / Bl ratios of the modified (PVA coated)12 inch Vs 15 inch driver we get 3.3 Vs 5.1 ie the 12 inch is 55% "faster" (can stop / start ) than the 15inch driver.
BUT the 15 inch driver is moving 60% less than the 12 inch for the same linear displacement (compression / rarefaction) so the big 15 inch is actually 5% faster than the 12 inch!!
Plus the 15 inch driver is more efficient, look carefully at the graphs only below 200 Hz, that's the only relevant area in your application. The 15 inch driver is 100dB for 1 watt at 1 meter over almost all of the 100Hz to 200Hz frequency band. This is very, very impressive for such a fast driver.
The 12 inch driver is on or under the 95dB line for 95% of the same frequency band, that 5dB difference on paper makes a very noticeable audible difference with music.
Plus the 15 inch has a 100mm voice coil Vs the 75mm coil in the 12 inch so can handle more power.
You can always add one or two subs at any time in the future and keep the 12 inch Beyma drivers above 100Hz, party on Garth....!
All the best
Derek.
Hi Telstar,
The Beyma SM 112/N is a great value for money product and will sound sweet with the Manger in a two way open baffle.
52g Mms / Bl of 17.2 = 3 which is very good for a 12 inch driver, it will be fast bass, i.e. textured, detailed and solid.
The compromises suit your design very well, as I understand your broad design remit is:
(1) High WAF / small cabinet.
(2) good dynamics but not the kind of high SPL AJ and I love!
(3) Future upgrade path avoiding redundant components.
The only slight technical compromises with this driver will be the medium / high Fs (for a 12 inch bass driver) will limit the usable low end extension in a VPL OB to around 40Hz.
Edit : You will need a baffle approx 50cm wide with VPL wings 550mm deep with the "shark bites" bringing the shallow point down to approx 24cm. The DEQX will tidy up any remaining peaks and can give you some 30Hz to 6oHz boost if required. But the Xmax is only 5.5mm so dont go crazy...!
The 38Hz "official" Fs is always plus or minus 5% to 10% in this price bracket for drivers. So you could be looking at anything from 35Hz to 41Hz real world Fs.
To compensate a little you can apply a few thin coats of cone damping material (good old water based PVA wood glue works very well for about £1.00 a tube! This will increase the Mms and therefore lower the Fs. Don't go crazy here but get some accurate scales and weigh out say 5g of PVA and apply this in multiple thin coats until each cone has its 5g applied.
This will drop the Fs by approx 4Hz (10%) getting you very close to your 30Hz target. If you have the patience you can spread the PVA over the back of the cone as well as the front.
Give the dust cap plenty of glue as its a very hard paper and needs some "calming down".
Be careful not get any PVA glue on the surround as this will stiffen it up and raise the Fs!!
It's actually very interesting to compare the SM 112 N with the Beyma SM 115 K, it has a Mms of 106g, a Bl of 20.5 so a ratio of 5.1 and its still great on vocals at cello at 200Hz.
Its Sd is 880 ( 60% more than the 550 of the SM 112N ) so its only having to move 40% as far with each compression / rarefaction compared to the 112 N.
Comparing the Mms / Bl ratios of the modified (PVA coated)12 inch Vs 15 inch driver we get 3.3 Vs 5.1 ie the 12 inch is 55% "faster" (can stop / start ) than the 15inch driver.
BUT the 15 inch driver is moving 60% less than the 12 inch for the same linear displacement (compression / rarefaction) so the big 15 inch is actually 5% faster than the 12 inch!!
Plus the 15 inch driver is more efficient, look carefully at the graphs only below 200 Hz, that's the only relevant area in your application. The 15 inch driver is 100dB for 1 watt at 1 meter over almost all of the 100Hz to 200Hz frequency band. This is very, very impressive for such a fast driver.
The 12 inch driver is on or under the 95dB line for 95% of the same frequency band, that 5dB difference on paper makes a very noticeable audible difference with music.
Plus the 15 inch has a 100mm voice coil Vs the 75mm coil in the 12 inch so can handle more power.
You can always add one or two subs at any time in the future and keep the 12 inch Beyma drivers above 100Hz, party on Garth....!
All the best
Derek.
Its all in the name...!
Piston drivers or Oscillation drivers?
I am posting this here as I hope I will be preaching to the converted for the most part, but I do expect to be attacked from all the other "piston is best" camp, especially from the guys who post on the DIY forums but are actually commercial speaker manufacturers.
Here goes anyway….!
The problem with so called "pistonic" drivers is this, they are never pistonic!
They can not function like a piston i.e. like the alloy pistons in an engine.
All cone, dome, ribbon, panels, stats, co-ax, and compression drivers are all "Oscillation" drivers i.e. mass on the end of a spring. Not a fixed rod with a finite mechanical range of forward and backwards motion.
Let's examine our audio pistons …..
Imagine looking side on at a clear plastic tube containing a ping-pong ball, this ball has a coil of copper wire wound round its circumference. The ping pong ball has a piece of elastic fixed to it and the other end of the elastic is fixed to one end of the tube. At the end of the tube where the elastic is fixed there is a ring of magnets around the outside of the tube. Let's assume the magnets are powerful and generate a perfectly symmetrical magnetic field and the elastic (spider and surround) is also 100% linear in its operation. (Big assumptions but pistonic theory needs all the help it can get!)
This is our "pistonic" driver! All it lacks is the paper cone around the ping pong ball, but that brings in aerodynamics which I'll touch on later.
We pass an electric current through the wire that's around the ball and hey presto the ball shoots forward inside the tube!
BUT the ball then shoots back (pulled by the elastic) and OVERSHOOTS its starting point! It then OSCILLATES out of control until all the kinetic energy / potential energy is slowly (compared to the initial transient acceleration) dissipated. The important bit is "compared to the initial transient / acceleration". i.e.The decay time is much greater than the rise time, by an order of magnitude in many drivers!
Music signals are all about transients, amplitude and ….Timing! All "real"
(i.e. not signal generators and sine waves) sounds, musical or snapping twig etc, are formed by an initial transient of air pressure and then a decay back to ambient pressure.
That's all we have to hear with, binary on /off, compression or rarefaction of the air, everything else is just decay of air pressure back to ambient.
So let's play some music through our ping pong ball speaker!
First up one single drum strike. Bang, the ball shoots forward causing a compression of the air in front of it (yes it does have to move through the air and yes aerodynamics do come into play!) it is propelled forward by the electrical impulse and simultaneously it is being retarded by the elastic band (the spider, surround and suspension) which is now storing this kinetic energy as potential energy.
So when the ball reaches the end of its forward motion it is now pulled backwards by the elastic band, and will overshoot its original starting point (carried past the start position by its own momentum) it behaves exactly as the laws of physics dictate, a mass on the end of a spring. It will oscillate! Back and forward until it dissipates all the energy in the elastic band.
So instead of the one clean drum strike you get one clean strike followed by a slowly diminishing number of ghost echoes.
This is the inherent mechanical failing with all pistonic drivers. Some display gross errors (heavy coned bass drivers) some marginal and some almost undetectable at low SPL's playing simple acoustic music. At life like SPL's and with more complex music 99% of all pistonic drivers fall apart, displaying gross ghost echoes (gross time domain distortion).
Now start to factor in real music i.e. before the driver has stopped oscillating from the first strike, bang here comes another and another and now a double bass and look out here comes the piano…! You get the picture, it’s the compounding of errors one on top of the next which never allows the cone or dome, ribbon or panel to actually start and stop on its marks.
To minimise the oscillations a general rule is the more efficient the driver the less oscillation it will display. Low Mms divided by high Bl gives you a guide figure to work with. The lower this number the better. Also always use the biggest Sd possible, if your driver is using more than 30% to 50% of its Xmax at 90dB to 100dB SPL's , use a bigger driver!
Just briefly on the aerodynamics, our ping pong ball is symmetrical so it is aerodynamically balanced, all cones are out of balance to some degree depending on profile. The fact that the drivers are only moving back and forward a short distance (plus and minus half an inch or half a millimetre it makes no difference) it’s the huge acceleration and deceleration that magnifies the effect. i.e. at walking pace the wind on your face is not noticeable, but at 100 miles per hour it will distort your cheeks! The fact that the distances and times are small makes no difference; the speakers must move and re-move the air mass in front and behind the cones hundreds (100Hz to 999Hz) and thousands 1,000Hz to 20KHz +) of times per second. The air mass in front of all cone drivers is actually measured and recognised by ALL driver manufacturers already. The MMS (expressed in grams) specification given for all drivers is the total weight of all the moving mass of the driver PLUS the weight of air in the cone profile. The manufactures know the problem is there but can't figure out (yet!) how to get round it.
To get a handle on the scale of this problem imagine you are being driving along at 100mph in an open top car, now hold out a 12 inch bass driver facing cone forward. Feel the force ? Now instantly turn the driver to face magnet first. Instantly there is a 30% to 70% (dependant on cone profile) reduction in the aerodynamic force. Now turn the driver back and forward 100 times a second (a 100Hz note) and you begin to get an idea of the scale of the problem!
Despite the above we can still get great results from cones / domes ribbons etc and modern materials and all the R&D are improving the performance all the time. I.e. The new Beyma TPL 150 is potentially the best pistonic driver ever made….. As Manger users we must use something from 20Hz up to the crossover point (150Hz min 400Hz for 120dB SPL's) but I believe we should pay more attention to minimising driver oscillation and aerodynamic errors.
I can already hear the residents of "Piston Village" sharpening their pitch forks so on with the body armour wait for the slings and arrows…..!
Cheers
Derek.
Piston drivers or Oscillation drivers?
I am posting this here as I hope I will be preaching to the converted for the most part, but I do expect to be attacked from all the other "piston is best" camp, especially from the guys who post on the DIY forums but are actually commercial speaker manufacturers.
Here goes anyway….!
The problem with so called "pistonic" drivers is this, they are never pistonic!
They can not function like a piston i.e. like the alloy pistons in an engine.
All cone, dome, ribbon, panels, stats, co-ax, and compression drivers are all "Oscillation" drivers i.e. mass on the end of a spring. Not a fixed rod with a finite mechanical range of forward and backwards motion.
Let's examine our audio pistons …..
Imagine looking side on at a clear plastic tube containing a ping-pong ball, this ball has a coil of copper wire wound round its circumference. The ping pong ball has a piece of elastic fixed to it and the other end of the elastic is fixed to one end of the tube. At the end of the tube where the elastic is fixed there is a ring of magnets around the outside of the tube. Let's assume the magnets are powerful and generate a perfectly symmetrical magnetic field and the elastic (spider and surround) is also 100% linear in its operation. (Big assumptions but pistonic theory needs all the help it can get!)
This is our "pistonic" driver! All it lacks is the paper cone around the ping pong ball, but that brings in aerodynamics which I'll touch on later.
We pass an electric current through the wire that's around the ball and hey presto the ball shoots forward inside the tube!
BUT the ball then shoots back (pulled by the elastic) and OVERSHOOTS its starting point! It then OSCILLATES out of control until all the kinetic energy / potential energy is slowly (compared to the initial transient acceleration) dissipated. The important bit is "compared to the initial transient / acceleration". i.e.The decay time is much greater than the rise time, by an order of magnitude in many drivers!
Music signals are all about transients, amplitude and ….Timing! All "real"
(i.e. not signal generators and sine waves) sounds, musical or snapping twig etc, are formed by an initial transient of air pressure and then a decay back to ambient pressure.
That's all we have to hear with, binary on /off, compression or rarefaction of the air, everything else is just decay of air pressure back to ambient.
So let's play some music through our ping pong ball speaker!
First up one single drum strike. Bang, the ball shoots forward causing a compression of the air in front of it (yes it does have to move through the air and yes aerodynamics do come into play!) it is propelled forward by the electrical impulse and simultaneously it is being retarded by the elastic band (the spider, surround and suspension) which is now storing this kinetic energy as potential energy.
So when the ball reaches the end of its forward motion it is now pulled backwards by the elastic band, and will overshoot its original starting point (carried past the start position by its own momentum) it behaves exactly as the laws of physics dictate, a mass on the end of a spring. It will oscillate! Back and forward until it dissipates all the energy in the elastic band.
So instead of the one clean drum strike you get one clean strike followed by a slowly diminishing number of ghost echoes.
This is the inherent mechanical failing with all pistonic drivers. Some display gross errors (heavy coned bass drivers) some marginal and some almost undetectable at low SPL's playing simple acoustic music. At life like SPL's and with more complex music 99% of all pistonic drivers fall apart, displaying gross ghost echoes (gross time domain distortion).
Now start to factor in real music i.e. before the driver has stopped oscillating from the first strike, bang here comes another and another and now a double bass and look out here comes the piano…! You get the picture, it’s the compounding of errors one on top of the next which never allows the cone or dome, ribbon or panel to actually start and stop on its marks.
To minimise the oscillations a general rule is the more efficient the driver the less oscillation it will display. Low Mms divided by high Bl gives you a guide figure to work with. The lower this number the better. Also always use the biggest Sd possible, if your driver is using more than 30% to 50% of its Xmax at 90dB to 100dB SPL's , use a bigger driver!
Just briefly on the aerodynamics, our ping pong ball is symmetrical so it is aerodynamically balanced, all cones are out of balance to some degree depending on profile. The fact that the drivers are only moving back and forward a short distance (plus and minus half an inch or half a millimetre it makes no difference) it’s the huge acceleration and deceleration that magnifies the effect. i.e. at walking pace the wind on your face is not noticeable, but at 100 miles per hour it will distort your cheeks! The fact that the distances and times are small makes no difference; the speakers must move and re-move the air mass in front and behind the cones hundreds (100Hz to 999Hz) and thousands 1,000Hz to 20KHz +) of times per second. The air mass in front of all cone drivers is actually measured and recognised by ALL driver manufacturers already. The MMS (expressed in grams) specification given for all drivers is the total weight of all the moving mass of the driver PLUS the weight of air in the cone profile. The manufactures know the problem is there but can't figure out (yet!) how to get round it.
To get a handle on the scale of this problem imagine you are being driving along at 100mph in an open top car, now hold out a 12 inch bass driver facing cone forward. Feel the force ? Now instantly turn the driver to face magnet first. Instantly there is a 30% to 70% (dependant on cone profile) reduction in the aerodynamic force. Now turn the driver back and forward 100 times a second (a 100Hz note) and you begin to get an idea of the scale of the problem!
Despite the above we can still get great results from cones / domes ribbons etc and modern materials and all the R&D are improving the performance all the time. I.e. The new Beyma TPL 150 is potentially the best pistonic driver ever made….. As Manger users we must use something from 20Hz up to the crossover point (150Hz min 400Hz for 120dB SPL's) but I believe we should pay more attention to minimising driver oscillation and aerodynamic errors.
I can already hear the residents of "Piston Village" sharpening their pitch forks so on with the body armour wait for the slings and arrows…..!
Cheers
Derek.
Hi Derek
I think you alluded to tweaking the motor in earlier posts... suppose one could make a nice field coil motor for the thing - how easy might it be to retrofit this to the MSW?
Ease of disassembly etc aside, what's the situation like with the backwave - from pics I've seen it looks like the motor would have to be very vented, i.e. very open at the back?
Best regards
Chris
I think you alluded to tweaking the motor in earlier posts... suppose one could make a nice field coil motor for the thing - how easy might it be to retrofit this to the MSW?
Ease of disassembly etc aside, what's the situation like with the backwave - from pics I've seen it looks like the motor would have to be very vented, i.e. very open at the back?
Best regards
Chris