Hi! I finish the project with acoustics ESS Tempest LS-5. It was necessary to arrange an impedance. I removed to me on other party of the ocean. I came in a disgusting condition. I redid registration, now it is acoustics of a tornado. VCh very wide reproduce panoramas.
Amazing how similar ideas pop up without knowing about them.
Whilst looking at old vintage microphones I noticed their suspension and figured if it worked 90 years ago it probably still is effective.
Took a 3 inch driver out of one of my OB and hung it via cantilevered bolts and rubber cord from a stand.
The measurements and baffle calcs in EDGE all say that the rolloff should be what a baffle 4 inches wide would have or nearly a tweeter. 0dB 800, +6 2500, -7 8000, +6 15,000, and so on. Then I ran test tones and it works down to right around 250 and then it all falls off a cliff 125 tones being nearly inaudible. So hearing, in practice, 250 works for this tiny solo 3 inch driver. paired with a large sub/woofer/mid to pick up the slack below 1500 using the rolloff should bring bass up.
So as Absoluty has done I will be making a 2-way OB with the top NOB and the bottom an OB with it and the baffle suspended so that the driver is not in contact with the baffle. Maximum isolation.
Playing around with styrofoam panels and magazines moving the towards and away from the 3inch driver the baffle effect becomes noticeable and usable *without* requiring contact or attachment to the driver.
The clearance is close - less than 5mm - but when done so the lower frequencies come up as they would on a baffle of width N.
This will be a large frame with three elements suspended;
-Tweeter-Mid (a widerange 3 to 6 inch driver)
-Mid-Bass (a woofer than has mechanical roll off at 1500-3000hz)
-The OB panel for the mid-bass
There will be no crossover as the NOB rolloff of the widerange mid-tweeter will be mated with the mechanical roll off of the FR of the subwoofer.
FR will probably be down to 125 or so on paper but in practice floor and wall boundary effects cause bass response to be "better than it should be"
Frames are large picture frames and the suspension is bungee cord and eye bolts..Drivers cantilever on the band via the bolt adjusted for centre of gravity and angle to listening seat.
Do I do measurements to see if it measures level? Nope. I listen. If I like it, I use it.
Heresy, I know.
Great question but since I have a dearth of measurement tech on hand I don't know.
The idea is more or less a tweeter/mid up top and two concentric circles below both suspended.
I have held/touched the cable holding the tweeter body (and this is just a wide range driver of smaller size in a no baffle setup with the very high rolloff endemic to this type of build) and close to the body there is some vibration but this tapers and is absobed by the rubber in the bungee cord. Supports have little or no vibration by touch. I am sure measurements would pick up some at a reduced level.
Linkwitz made his baffles to work with the tweeter and mid for baffle adaption no doubt - narrow as can be but not too narrow. The shape also is likely well thought out and modeled.
I would never in several lifetimes compare my build to Linkwitz, but it seems likely that this odd method of decoupling would reduce resonance some more.
It's hanging suspended in air with rubber cords separating the woofer from the frame from the tweeter. Any vibration from one driver to the other would have to travel through two rubber chords and the frame. I feel nothing by touch.
One could go one step more and make a separate frame for each. Zero interaction on the mechanical level, just acoustic vibration.
Did I mention that the WAF of this is nil? I think that is obvious...
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I agree completely about using chains. I was surprised as vibrations are non-existent with this solution. I have two 12 inch working hard in bass without any vibrations in the frame structure.
Thanks Darkheart,
But the body of the speaker itself ? You feel some light vibrations. what about small signals (if wide band and rigid cone) if the body has himself vibrations who can cancel (maybe, I don't know in fact!) some of the cone mouvements by nulling them (opposite mv or something near ?
Maybe a question of weight... StigErik use hanging RD75 from G&B....
In fact I asking myself how can be a coherent point source between a tweeter and a mid with a gap with no bafle between the both ? Better because no nods & reflections between both instead a standalone bafle in relation to the sides and the top ?????
With the few mouvement of a tweeter I'm really asking me how much its body can influence the sound (transcient, phase).
My understanding was the decoupling of a front panel was more to avoid the enclosure to have a frequency beat (resonances) coupled with the ones of the drivers... which is complicate because classic cone drivers need a stable reference (eg : Dynaudio with some metal bafle glued on a wood enclosure with a special damped glue !)
Very interresting this concept of hanging....I see a huge advantage : time alignement because no common frame and cabinet ! Less intrusive than a 100% FIR correction no... some say there is a difference between physuc time alignement and digital one, because smoother transition even if digital FIR i sinvolved ! Who wan we believe ! I like on the paper the idea of passive corrections but have to say cellulars are more easier than smoke clouds for communication !
We need Alnico tweeters... more heavy
!
regards
But the body of the speaker itself ? You feel some light vibrations. what about small signals (if wide band and rigid cone) if the body has himself vibrations who can cancel (maybe, I don't know in fact!) some of the cone mouvements by nulling them (opposite mv or something near ?
Maybe a question of weight... StigErik use hanging RD75 from G&B....
In fact I asking myself how can be a coherent point source between a tweeter and a mid with a gap with no bafle between the both ? Better because no nods & reflections between both instead a standalone bafle in relation to the sides and the top ?????
With the few mouvement of a tweeter I'm really asking me how much its body can influence the sound (transcient, phase).
My understanding was the decoupling of a front panel was more to avoid the enclosure to have a frequency beat (resonances) coupled with the ones of the drivers... which is complicate because classic cone drivers need a stable reference (eg : Dynaudio with some metal bafle glued on a wood enclosure with a special damped glue !)
Very interresting this concept of hanging....I see a huge advantage : time alignement because no common frame and cabinet ! Less intrusive than a 100% FIR correction no... some say there is a difference between physuc time alignement and digital one, because smoother transition even if digital FIR i sinvolved ! Who wan we believe ! I like on the paper the idea of passive corrections but have to say cellulars are more easier than smoke clouds for communication !
We need Alnico tweeters... more heavy
!regards
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Eldam,
please read this thread: http://www.diyaudio.com/forums/multi-way/177111-physics-swinging-speakers.html
please read this thread: http://www.diyaudio.com/forums/multi-way/177111-physics-swinging-speakers.html
The advantage of FIR does not have anything to do with physical time alignment. The advantage is that you can do frequency dependant time alignment. Thus you can do reverse all passes and correct the group delay of the speaker.
Digital time alignment is as simple as just delaying the signal on the channel, there is absolutely no sound quality degradation.
Maybe I got lucky with my choice.
I found some bungee cord like bands, 1cm wide 2 mm thick and 2 metres long in an awful green pattern, but it's long, it's elastic and the flat area gives the cantilever screws something to fetch onto. So the bolts rest on a narrow 1cm platform, of sorts, of rubber.
I can easily angle this up or down by moving the driver. About 15 degrees vertical is the maximum leeway.
Modeled on EDGE and put two 78mm $1 drivers into two styrene panels 1m x 2 m and the soundstage and midrange and vocal accuracy is absurd. There is a foam resonance that is hard to get rid of and the panels are not stiff, no surprise with styrene, but my reaction to the presentation of point source instruments in 3-D space was "now, THAT is more like it...""
Running test tones and listening the response seems to get down to around ~55hz, audible 30 hz at low levels, though. This not possible without the door sized baffle, of course.
The 3 inch drivers are placed 109cm off the floor and 63cm from the wall of each panel mirror image pairs. I am tall and I prefer my listening height to be rather elevated.
$5 of drivers and styrene has a far superior soundstage to a 2-way with $125 in drivers, xo, cabinet and parts. I suppose this should not be a surprise.
I can get plywood sheets and laminate them to add stiffness and replace the styrene. Perhaps drill holes and place bolts/nuts to clamp them firmly together after they have been glued. 3 layers should stiffen enough. A frame would make sense but the wood situation does not permit.
Obtaining materials is difficult - there is no lumber in the region wider than 20 or 30 mm and thicker than 5mm. I shall have to make my own. MDF or plywood is the best choice. Cutting boards are good, too. Some of them are very large - 150 cm by 100m - more than large enough.
Once I get the ""lumber'" made I can then order some Alpair 10's and put a real driver in this.
They fill the end of the room, about 40% of the width and half way to the ceiling, which is very high.
Listening to these from the adjacent room, that backwave sound is addictive. Now on to some real drivers...
Running test tones and listening the response seems to get down to around ~55hz, audible 30 hz at low levels, though. This not possible without the door sized baffle, of course.
The 3 inch drivers are placed 109cm off the floor and 63cm from the wall of each panel mirror image pairs. I am tall and I prefer my listening height to be rather elevated.
$5 of drivers and styrene has a far superior soundstage to a 2-way with $125 in drivers, xo, cabinet and parts. I suppose this should not be a surprise.
I can get plywood sheets and laminate them to add stiffness and replace the styrene. Perhaps drill holes and place bolts/nuts to clamp them firmly together after they have been glued. 3 layers should stiffen enough. A frame would make sense but the wood situation does not permit.
Obtaining materials is difficult - there is no lumber in the region wider than 20 or 30 mm and thicker than 5mm. I shall have to make my own. MDF or plywood is the best choice. Cutting boards are good, too. Some of them are very large - 150 cm by 100m - more than large enough.
Once I get the ""lumber'" made I can then order some Alpair 10's and put a real driver in this.
They fill the end of the room, about 40% of the width and half way to the ceiling, which is very high.
Listening to these from the adjacent room, that backwave sound is addictive. Now on to some real drivers...
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You don't have to have a stiff baffle, lossy baffles are awesome! I did an experiment with a wool baffle and found that with my 6.5" mid I got almost identical low frequency gain with a wool baffle ( even down at 300 hz! ) as with a wood baffle but none of the dipole peak issues. In the end my speaker now uses wool baffles =)
Wow, I listened to a variety of acoustic selections - Rifles, Adele, Aborne Toxic Event, Maroon 5, etc, and the uncanniness is just what I had been missing. On Faces Every Picture I can hear the drums off in the corner of the studio 30 feet away in the right hand corner and the sound of the room is clear.
This with $5 of drivers and materials. The drivers are $2 or $1. A pair.
I look forward to rolling some Teslas and Svetlanaa into the amp and the arrival of the Alpairs.
Love that OB sound!
This with $5 of drivers and materials. The drivers are $2 or $1. A pair.
I look forward to rolling some Teslas and Svetlanaa into the amp and the arrival of the Alpairs.
Love that OB sound!
What are they? Is that I tiny little horn super tweeter just above the woofer?
I'm still not sold on the string baffle cover thing. Surely its just asking for diffraction and resonance issues. Admitadly I haven't heard enough about the materials and mechanics involved.
Looks nice though...
I'm still not sold on the string baffle cover thing. Surely its just asking for diffraction and resonance issues. Admitadly I haven't heard enough about the materials and mechanics involved.
Looks nice though...
The drivers are $1 or $2 each and the styrene was $1.50 per sheet, 996mm by 1996mm.
All for under 4 GBP sterling.
All for under 4 GBP sterling.
An externally hosted image should be here but it was not working when we last tested it.
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EDGE modeling. 65mm driver diameter 78mm case diametre on a 1m x 2m styrofoam baffle. Fasteners are 18/8 40mm x 5mm bolts with rubber washers for and aft, metal washers, and flange bolts in the rear. All were tightened until the foam compressed 2 mm or so. Blu Tack used to dampen some magnet>foam vibrations which with styrene sound as though a mosquito is in the room.
Next OB the face of the driver will get a Blu Tack circular bead to seal the front to the baffle seamlessly.
Some of these drivers have a circular mount face with a U-shaped cross section, not ideal for sealing.
There were flatter responses 300-1000 but that placed the driver 1.2m off the floor, too high for seated listening.
The size of the driver has little effect on the FR from 350 - 1000 with this placement and panel size unless one uses a very large driver 450mm+. I get plenty of backwave air and space with this big panel even though the two fill 40% of the width of the room and are more than halfway to the ceiling.
It's really a testament to the OB principle that this junk setup still has the same strengths with nearly the cheapest materials possible. I don't want nor miss bass, so a second driver and XO are not part of this build family. More drivers arriving, a variety of 3, 4 and 6.5 inches with the Alpairs being the best of the lot.
Behind these panels are the 2-way sealed on their stands, they have far better drivers than this OB mock-up. On the floor is the cutting board OB that sat on the floor, it will get the future drivers. OB for the bed room, den/pc station and living room and those transparent plastic drivers will go in a PVC sono-tube widerange tube that lays on the transom in the bath.
I just looked at where others placed their drivers in OB's and began around there. No need to reinvent the wheel. The classic Wharfedales are good inspiration as well.
Next OB the face of the driver will get a Blu Tack circular bead to seal the front to the baffle seamlessly.
Some of these drivers have a circular mount face with a U-shaped cross section, not ideal for sealing.
There were flatter responses 300-1000 but that placed the driver 1.2m off the floor, too high for seated listening.
The size of the driver has little effect on the FR from 350 - 1000 with this placement and panel size unless one uses a very large driver 450mm+. I get plenty of backwave air and space with this big panel even though the two fill 40% of the width of the room and are more than halfway to the ceiling.
It's really a testament to the OB principle that this junk setup still has the same strengths with nearly the cheapest materials possible. I don't want nor miss bass, so a second driver and XO are not part of this build family. More drivers arriving, a variety of 3, 4 and 6.5 inches with the Alpairs being the best of the lot.
Behind these panels are the 2-way sealed on their stands, they have far better drivers than this OB mock-up. On the floor is the cutting board OB that sat on the floor, it will get the future drivers. OB for the bed room, den/pc station and living room and those transparent plastic drivers will go in a PVC sono-tube widerange tube that lays on the transom in the bath.
I just looked at where others placed their drivers in OB's and began around there. No need to reinvent the wheel. The classic Wharfedales are good inspiration as well.
First shot at open baffle, near miss , I guess. The port opening is 4", directly behind the neo 10, tuned to act as a 300 hz Helmholtz resonator, AND act as a quarterwave transmission line to fluff up the neo 10, which is weak from 800 to 150 hz on a plain open baffle.
The tweeter is a neo 3 , with the cup removed, and a 4" hole behind it in the rear baffle.
These are actively crossed over, 4th order, at 175hz, and 3000hz.
I'm currently using a tuned to 25 hz transmission line sub, but am wondering if a smaller, sealed isobaric sub might be better suited to match these(no box resonances through the isobaric loading?), as I've already got two nice 10" sub drivers and a decent plate amp.
The tweeter is a neo 3 , with the cup removed, and a 4" hole behind it in the rear baffle.
These are actively crossed over, 4th order, at 175hz, and 3000hz.
I'm currently using a tuned to 25 hz transmission line sub, but am wondering if a smaller, sealed isobaric sub might be better suited to match these(no box resonances through the isobaric loading?), as I've already got two nice 10" sub drivers and a decent plate amp.
Attachments
Second shot, much easier build.
These are some isodynamic ribbons I got on clearance pricing a couple years back, paired up with some 1970's vintage Seas tv 21 woofers, as open baffle as I could make them. They list at 96 db/watt, 3.5 dcr, and a qts of 0.707.
They sound wonderful, crossed over at 150 hz, and 2500 hz.
Awaiting some vintage alnico Peerless 16 ohm paper tweeters, possibly a more suitable match.
I recently tried some $3.66 dynavox phenolic ring radiators ( the cone is paper) and was amazed at how good these sound!
Won't turn up my nose at paper tweeters without a listen ever again.
Very little eq'ing required to get great sound out of those.
These are some isodynamic ribbons I got on clearance pricing a couple years back, paired up with some 1970's vintage Seas tv 21 woofers, as open baffle as I could make them. They list at 96 db/watt, 3.5 dcr, and a qts of 0.707.
They sound wonderful, crossed over at 150 hz, and 2500 hz.
Awaiting some vintage alnico Peerless 16 ohm paper tweeters, possibly a more suitable match.
I recently tried some $3.66 dynavox phenolic ring radiators ( the cone is paper) and was amazed at how good these sound!
Won't turn up my nose at paper tweeters without a listen ever again.
Very little eq'ing required to get great sound out of those.
