Grant, The question you asked about the series resistor to parallel components: I believe you asked if you had to subtract its' value from the DC resistance of the component..........I modelled it both ways and came to conclude that I will subtract the value of the DC resistance from the chosen resistor so that the combination of DCR and resistor value equal the simulated response target.........I found in the simulations, that they did a very nice job of "rounding out" the response curve and smoothing the summed response without adversly affecting SPL.....Thank You SO MUCH Tinitus for your input on this.........It seemed to be a revelation, which really kick started my understanding here......In addition, this is why I ordered additional resistors, so that I could tweak by ear if need be......Same thing with the capacitors...................PMS= Poor Mans Strad.............got it, and will, for the fun of it, familiarize myself with it...........I've got most of the artists you guys have mentioned......Let's not forget Holsts' Planets..............Grant, if you are interested in Spyro Gyra........I might recommend "Catching The Sun" and "Incognito"............Great Stuff.....Grant, If there is anything I can do to help with your FRD files etc..........Gimme a shout..............Best Wishes............Omni
Hi everyone!
Many thanks for all your valuable advice on my 'attenuation and series resistors' questions. I've noted your answers for future reference...when I finally get there!
Omni,
I been trying to get Unibox to work in my free spreadsheets. Another no go unfortunately! Specific XL macros are required, so I get a 'missing script message'. I can input driver data, but can't do anything with it, lol. So thats the end of FRC sims for me at the moment. My options now are these:
1) my 'preferred least cost and quickest method': ...copy Troels PMS xo verbatim, except adding a partial Zobel to the P25, try to source the low DCR coils locally then buy the MCA15 & 27TFFC's asap. Then 'proto' the xo. It might sound very much 'off' in the hifi jargon, lol,
but you never know it could be acceptable to me as a first try, and probably better than a 'textbook xo'! Also at least I'll know that the amp will be safe! I could then change the baffle and innards to replicate Troels PMS - then I imagine it could be very good?
2) save up for Office 2000 (2003?) if still available. Do all the FRC stuff....then eventually buy all the bits. ( This option could take quite a while! )
Omni, I think Roman said ( in his FRC 'tute' ) that Unibox can model infinite baffles but I wonder about (smaller) curved ones. Would you by chance, happen to know? Thanks so much for your repeated offer of FRC help. At some stage I might gratefully take you up on that in a minimal way as possible, but only when your project is completed and you're otherwise not too busy. I had hoped to buy my drivers a month ago, so the way things are panning-out it could be soonish - I hope!
Maybe just for fun have a look at Troels Acapella too while you're there? thanks Omni, grant
Many thanks for all your valuable advice on my 'attenuation and series resistors' questions. I've noted your answers for future reference...when I finally get there!
Omni,
I been trying to get Unibox to work in my free spreadsheets. Another no go unfortunately! Specific XL macros are required, so I get a 'missing script message'. I can input driver data, but can't do anything with it, lol. So thats the end of FRC sims for me at the moment. My options now are these:
1) my 'preferred least cost and quickest method': ...copy Troels PMS xo verbatim, except adding a partial Zobel to the P25, try to source the low DCR coils locally then buy the MCA15 & 27TFFC's asap. Then 'proto' the xo. It might sound very much 'off' in the hifi jargon, lol,
but you never know it could be acceptable to me as a first try, and probably better than a 'textbook xo'! Also at least I'll know that the amp will be safe! I could then change the baffle and innards to replicate Troels PMS - then I imagine it could be very good?
2) save up for Office 2000 (2003?) if still available. Do all the FRC stuff....then eventually buy all the bits. ( This option could take quite a while! )
Omni, I think Roman said ( in his FRC 'tute' ) that Unibox can model infinite baffles but I wonder about (smaller) curved ones. Would you by chance, happen to know? Thanks so much for your repeated offer of FRC help. At some stage I might gratefully take you up on that in a minimal way as possible, but only when your project is completed and you're otherwise not too busy. I had hoped to buy my drivers a month ago, so the way things are panning-out it could be soonish - I hope!
Maybe just for fun have a look at Troels Acapella too while you're there? thanks Omni, grant
Omni,
pls see this thread: http://www.diyaudio.com/forums/showthread.php?threadid=96296
Frankie version 3 outside? hehe, sorry, I just couldn't resist this! considering your weather....
pls see this thread: http://www.diyaudio.com/forums/showthread.php?threadid=96296
Frankie version 3 outside? hehe, sorry, I just couldn't resist this! considering your weather....
Grant.........I wonder if snow has good acoustic qualities..........ie...good damping factor................lol.........I really got a kick out of that...........I don't know if Unibox or Baffle Diffraction Simulator can model small curved baffles or not..........When I was working with the programs, I cannot recall seeing any sections on the program dealing with curved baffles........I am curious though..........How large is the baffle you are considering, relative to the size of your driver?.............Depending on its' size, relative to your drivers, you may be able to simply model it as an infinite baffle.............I am gonna log onto Troels here shortly and check out those projects you mentioned...........................Omni
Grant, I checked out those projects......It seems like the PMStrad uses more basic drivers, where the Accapella uses the Excel series from SEAS..........PMStrad crossover may be more reasonable, given your driver selection?................Do you intend to create a curved baffle, similar to the PMStrad?................Looks like a fun endeavor............................Omni
Hi,
I can tell you this ...... with the right care just about anything reasonable can play .... it rarely gets better than good.... and if your ears like it, then it is good 😉
I can tell you this ...... with the right care just about anything reasonable can play .... it rarely gets better than good.... and if your ears like it, then it is good 😉
Omni,
I'm glad you got a chuckle from the 'Frosty Frankie' link! Maybe my 'curved baffle' question applies more to BDS, oops, I'm sorry, I haven't read any of that yet - its all new to me still! However, * I assume * that properly curved baffles (when done correctly) will reduce the +- 2.5dB maximum diffraction ripple of square edges to almost zero? I'm not sure, but I believe this to be true. ( Still, I'm wondering why Troels hasn't offset the M&T 'vertically' in the PMS?
- but there must be a valid reason not to! ...maybe its insignificant?)
My current baffles are 32cm wide , (Troels 3WayCassic is 30cm), the PMS is 52cm wide and heavily curved.
(Troels uses the Seas 8" CA22 woofer in both designs, but it has a breakup? mode)
Without doubt, the individual BStep has been 'factored into' each xo design. And, of course, any modifications, would need to address the 'issues', lol,.... that almost sounded, learn-ed of me - haha!
Omni, I possibly should have said that I read Troels site for, (imo), great ideas and learning for me. In that sense too, its a fantastic resource (yes I'm a Troels Fan!) the PMS being a great design is quite possibly adaptable to my situation. I recommended you read the Acapella variants because of the similar trapezoid boxes only. Its all good fun!
I have some great news! I got Unibox working at the local library! (but unknown and limited time to access), we'll see how we go. I probably will copy the PMS xo, initially, but I'll see how far I can get with FRC. The PMS curved baffle is, I believe, 'do-able' but a hassle...I'll let you know! Re: Spyro Gyra - still trying to D/L your tracks....
Tinitus,
Wise words there! thank you very much. Would you please inform us some more of your 'tweaking' experiences? I truly would like to know more!
Thanks to everyone and also to casual readers of this thread. As always, everyone is welcome here! best wishes, grant
I'm glad you got a chuckle from the 'Frosty Frankie' link! Maybe my 'curved baffle' question applies more to BDS, oops, I'm sorry, I haven't read any of that yet - its all new to me still! However, * I assume * that properly curved baffles (when done correctly) will reduce the +- 2.5dB maximum diffraction ripple of square edges to almost zero? I'm not sure, but I believe this to be true. ( Still, I'm wondering why Troels hasn't offset the M&T 'vertically' in the PMS?
- but there must be a valid reason not to! ...maybe its insignificant?)
My current baffles are 32cm wide , (Troels 3WayCassic is 30cm), the PMS is 52cm wide and heavily curved.
(Troels uses the Seas 8" CA22 woofer in both designs, but it has a breakup? mode)
Without doubt, the individual BStep has been 'factored into' each xo design. And, of course, any modifications, would need to address the 'issues', lol,.... that almost sounded, learn-ed of me - haha!
Omni, I possibly should have said that I read Troels site for, (imo), great ideas and learning for me. In that sense too, its a fantastic resource (yes I'm a Troels Fan!) the PMS being a great design is quite possibly adaptable to my situation. I recommended you read the Acapella variants because of the similar trapezoid boxes only. Its all good fun!
I have some great news! I got Unibox working at the local library! (but unknown and limited time to access), we'll see how we go. I probably will copy the PMS xo, initially, but I'll see how far I can get with FRC. The PMS curved baffle is, I believe, 'do-able' but a hassle...I'll let you know! Re: Spyro Gyra - still trying to D/L your tracks....
Tinitus,
Wise words there! thank you very much. Would you please inform us some more of your 'tweaking' experiences? I truly would like to know more!
Thanks to everyone and also to casual readers of this thread. As always, everyone is welcome here! best wishes, grant
Hi,
I posted this way back in my second post in this thread
and have mentioned them several times since.
Unless you are rebuilding your boxes for a large baffle use the
3 way classic drivers and crossover as your starting point.
/sreten.
OK...."tweaking experiences...."
Actually I dont tweak so much any more - with a good sounding speaker I dont believe its that important
But again, a different room and all could change
Years ago i did lots of tweaking
I settled on cork feet underneath elektronics, especially CD - with a baseplate of granite, but theres a very fine balance between soft and hard
I also found it to be important that toroids dont touch the chassis and that there is no iron involved around it, and that it should be able to breathe - air should be able to pass through it
Crosscoils
Use the best you can afford
Fore big ones use special toroid crosscoils, they are immune to crosstalk
fore the smaller use aircore
On midrange the best there is foil with wax/paper
Air cores are best placed wide appart, and those close together should be oriented properly to minimize interference
Condensators
In my experience theres a lot of "hype" in this
Once I tried a very expencive one, and lots of very experienced people were crazy about it - I found it to be the absolute worst component in my system
So today I only use ordinary ones
I dont neglect that some of those expencive oil/paper foil C could be woth something, but I really dont bother any more
Resistor
Same thing actually
Non inductive are said to be good - another "hype", well I guess I will have to try them some day
Wire
Well, I have all sorts of wire all over the place... and in my system
Main thing, I prefer solid core and rather thin ones
Silvered cobber is the absolute worst
Pure silver can be good
Pure cobber always work
AT THE MOMENT I PREFER RATHER THIN TINNED COBBER
Sleve/insulation - polypropylene is said to be the worst and cheap there is, I cant say really
silk or cotton is good, but again I am not fanatic about it
I think my conclusion today is that good welladjusted and balanced design is what matters the most
Actually I dont tweak so much any more - with a good sounding speaker I dont believe its that important
But again, a different room and all could change
Years ago i did lots of tweaking
I settled on cork feet underneath elektronics, especially CD - with a baseplate of granite, but theres a very fine balance between soft and hard
I also found it to be important that toroids dont touch the chassis and that there is no iron involved around it, and that it should be able to breathe - air should be able to pass through it
Crosscoils
Use the best you can afford
Fore big ones use special toroid crosscoils, they are immune to crosstalk
fore the smaller use aircore
On midrange the best there is foil with wax/paper
Air cores are best placed wide appart, and those close together should be oriented properly to minimize interference
Condensators
In my experience theres a lot of "hype" in this
Once I tried a very expencive one, and lots of very experienced people were crazy about it - I found it to be the absolute worst component in my system
So today I only use ordinary ones
I dont neglect that some of those expencive oil/paper foil C could be woth something, but I really dont bother any more
Resistor
Same thing actually
Non inductive are said to be good - another "hype", well I guess I will have to try them some day
Wire
Well, I have all sorts of wire all over the place... and in my system
Main thing, I prefer solid core and rather thin ones
Silvered cobber is the absolute worst
Pure silver can be good
Pure cobber always work
AT THE MOMENT I PREFER RATHER THIN TINNED COBBER
Sleve/insulation - polypropylene is said to be the worst and cheap there is, I cant say really
silk or cotton is good, but again I am not fanatic about it
I think my conclusion today is that good welladjusted and balanced design is what matters the most
Hi Sreten,
I didn't intend to offend you in any way - quite the opposite in fact! Yes, of course...you made me aware of Troels site looong ago AND suggested the PMS and the drivers, and and and...SO many things!
All of which I am truly very grateful indeed. Without your, Omni and tinitus valuable help I'd still be totally lost!
It goes without saying that I credit your advice! 49 pages have my 'thank-you's' somewhere and other threads as well! I re-posted your Troels link for Omni's information.
Thanks again for your 3WayClassic xo reference. I was initially 'concerned' (too strong a word?) about the 550?Hz xo-point. But still have an open mind of course. Troels also mentioned that a 'stand' with a front 'plate' would effectively increase the baffle length and throw the xo 'out of whack' (my baffles are 190mm longer). This caused confusion for me as I had no FRC tools then to model with. So, I'm still very positive about your suggestion and when I can FRC sim everything, I'll definitely pursue it. Thanks, grant
I didn't intend to offend you in any way - quite the opposite in fact! Yes, of course...you made me aware of Troels site looong ago AND suggested the PMS and the drivers, and and and...SO many things!
All of which I am truly very grateful indeed. Without your, Omni and tinitus valuable help I'd still be totally lost!
It goes without saying that I credit your advice! 49 pages have my 'thank-you's' somewhere and other threads as well! I re-posted your Troels link for Omni's information.
Thanks again for your 3WayClassic xo reference. I was initially 'concerned' (too strong a word?) about the 550?Hz xo-point. But still have an open mind of course. Troels also mentioned that a 'stand' with a front 'plate' would effectively increase the baffle length and throw the xo 'out of whack' (my baffles are 190mm longer). This caused confusion for me as I had no FRC tools then to model with. So, I'm still very positive about your suggestion and when I can FRC sim everything, I'll definitely pursue it. Thanks, grant
Tinitus, wow, thank you!
Just some naiive comments from me here....
From what I have read, the room response adds a lot in the lower bass. And consequently would 'swamp' (increase?) any actual response? I have no idea really...any thoughts you have would very much help me!
Toroids in xo's is a new idea for me, but I can appreciate the benefits. Initially I thought they were meant for the amplifiers output stage...but a 'thread' in here says it looks beneficial to speaker design!
Re: capacitors .. can you *really* hear any difference between a bi-polar electrolyitic and a metallized polypropylene?
Re: resistors...the only ones I have access to are wire-wound...is the inductance ok? please?
I'm surprised about your comments on wire? I thought wire was err, wire? Is all this OFCopper stuff valid , do you think?
Thanks Tinitus, I hope my remarks are ok with you? cheers, grant
Just some naiive comments from me here....
From what I have read, the room response adds a lot in the lower bass. And consequently would 'swamp' (increase?) any actual response? I have no idea really...any thoughts you have would very much help me!
Toroids in xo's is a new idea for me, but I can appreciate the benefits. Initially I thought they were meant for the amplifiers output stage...but a 'thread' in here says it looks beneficial to speaker design!
Re: capacitors .. can you *really* hear any difference between a bi-polar electrolyitic and a metallized polypropylene?
Re: resistors...the only ones I have access to are wire-wound...is the inductance ok? please?
I'm surprised about your comments on wire? I thought wire was err, wire? Is all this OFCopper stuff valid , do you think?
Thanks Tinitus, I hope my remarks are ok with you? cheers, grant
room response
Thats the trick of getting the design right
In my system a LCR "notch"(?) is necessary to deal with driver/box ressonanse - without it bass is really not very good
also, from time to time I experience that even small changes elsewhere in the crossover affects bass precission, pretty much really
But it very much depends on driver, size, and design, and your room and perhaps equipment to be used in the system, music and so forth
hear the difference
Ofcourse, or else none of this would matter much
BUT, differences heard in a direct comparison, doesnt mean that one or the other component cant be used
Bipolar in bass is ok, and even BlackGate makes bipolar intended for crossover - if you find a good one it might be better than cheap poly
resistor
as said, I use ordinary wirewound and it works ok - I have tried to "strip" them with some benefit, but having done many hundreds of adjustments its a bit difficult
OFC wire
Some say wire is wire
There are some that claim to make special stressfree cobber, but its expencive
Plain simple solid core wire as the ones used in houses will do
Problems really first begins if you use very special wire design
mind you, many cheap materials has found its way to hifi, ending up as expencive audiophile components with fancy labels - kind of like selling special sand in the desert
Thats the trick of getting the design right
In my system a LCR "notch"(?) is necessary to deal with driver/box ressonanse - without it bass is really not very good
also, from time to time I experience that even small changes elsewhere in the crossover affects bass precission, pretty much really
But it very much depends on driver, size, and design, and your room and perhaps equipment to be used in the system, music and so forth
hear the difference
Ofcourse, or else none of this would matter much
BUT, differences heard in a direct comparison, doesnt mean that one or the other component cant be used
Bipolar in bass is ok, and even BlackGate makes bipolar intended for crossover - if you find a good one it might be better than cheap poly
resistor
as said, I use ordinary wirewound and it works ok - I have tried to "strip" them with some benefit, but having done many hundreds of adjustments its a bit difficult
OFC wire
Some say wire is wire
There are some that claim to make special stressfree cobber, but its expencive
Plain simple solid core wire as the ones used in houses will do
Problems really first begins if you use very special wire design
mind you, many cheap materials has found its way to hifi, ending up as expencive audiophile components with fancy labels - kind of like selling special sand in the desert
Thanks Tinitus,
Your reply was very helpful. I think I'll buy the best capacitors for the tweeter and mid, that I can afford, and as you suggest use AC power type wire. Trying to compensate for room response seems really tricky
and probably well beyond me at this stage. My problem is trying to source good quality, low DCR inductors that are affordable, here in Au.
best wishes, grant
Your reply was very helpful. I think I'll buy the best capacitors for the tweeter and mid, that I can afford, and as you suggest use AC power type wire. Trying to compensate for room response seems really tricky
and probably well beyond me at this stage. My problem is trying to source good quality, low DCR inductors that are affordable, here in Au.
best wishes, grant
grantnsw said:
Hi,
Hmmm........ why bother with low DCR if its not needed ?
Careful design can exploit the DCR of the inductors, e.g. modify the
Q of the bass unit in box for example for a better bass tuning, or the
box can be designed for bass unit + DCR value - not the paper specs.
I completely agree.
🙂/sreten.
Hi Sreten and thanks!
Re: " why bother with low DCR if its not needed ? " ....absolutely! I couldn't agree more, but ...I'd like to emphasize 'not', please.
I'm referring to your comment on page 48 , ie , just use a coil with DCR=2.2 ohms. This seems a great idea to me as it would allow cheaper coils to be used.
However, (steer me on the right path here again! please), I read somewhere once, that coils with 'much' higher DCR's eg 2.2 would heat
up more and thus reduce performance. Is this incorrect and therefore not an issue, please?
Re: " Careful design can exploit the DCR of the inductors " <---seems entirely logical to me as well. Maybe some time in the future I'll understand the woofer Q in box repurcussions for bass tuning! Anyway, thanks,...grant
Re: " why bother with low DCR if its not needed ? " ....absolutely! I couldn't agree more, but ...I'd like to emphasize 'not', please.
I'm referring to your comment on page 48 , ie , just use a coil with DCR=2.2 ohms. This seems a great idea to me as it would allow cheaper coils to be used.
However, (steer me on the right path here again! please), I read somewhere once, that coils with 'much' higher DCR's eg 2.2 would heat
up more and thus reduce performance. Is this incorrect and therefore not an issue, please?
Re: " Careful design can exploit the DCR of the inductors " <---seems entirely logical to me as well. Maybe some time in the future I'll understand the woofer Q in box repurcussions for bass tuning! Anyway, thanks,...grant
Omni,
Great news that you're ready to start building the crossovers and do initial testing soon! I'm sure the Opening Night performance will be a grand gala event! Possibly followed up with a little fine-tuning maybe, (not!) So, I don't want to bother you too much right now about BDS simulations. When you can, please keep us all posted, ...grant (I too am eager to find out what they sound like!)
Great news that you're ready to start building the crossovers and do initial testing soon! I'm sure the Opening Night performance will be a grand gala event! Possibly followed up with a little fine-tuning maybe, (not!) So, I don't want to bother you too much right now about BDS simulations. When you can, please keep us all posted, ...grant (I too am eager to find out what they sound like!)
Hi,
You already know what I think about simplistic design, be careful.
See here for "New Qts with series inductor"
http://www.mhsoft.nl/spk_calc.asp
You can also use this to calculate the effect of adding attenuation
to a midrange or tweeter if you know its original parameters.
You need to calculate the impedance seen by the driver assuming
the amplifier is a short. e.g. a L-pad with say 3.3R series and 15R
parallel gives a source resistance of 2.7R, plug into above.
For : http://www.partsexpress.com/pdf/264-524.pdf with 2.7R
Qts goes from 0.77 to 1.0.
Ferrofluid tweeters are much less affected.
🙂/sreten.
You already know what I think about simplistic design, be careful.
See here for "New Qts with series inductor"
http://www.mhsoft.nl/spk_calc.asp
You can also use this to calculate the effect of adding attenuation
to a midrange or tweeter if you know its original parameters.
You need to calculate the impedance seen by the driver assuming
the amplifier is a short. e.g. a L-pad with say 3.3R series and 15R
parallel gives a source resistance of 2.7R, plug into above.
For : http://www.partsexpress.com/pdf/264-524.pdf with 2.7R
Qts goes from 0.77 to 1.0.
Ferrofluid tweeters are much less affected.
🙂/sreten.
Hi Sreten,
Thanks for the links! About 'simplistic design' , well, err, I'm not totally certain as to what aspect of xo design you're referring to? But I'll go back over your previous posts and try to figure it out!
Unfortunately, still , some of your insightful advice goes way over my head, but I like to persevere as best I can, and will follow up your links. I briefly looked at your 'mhsoft' link, but, at the time, didn't know
how to use it. So my next question might be erroneous...
Would heat generated from a higher DCR coil degrade performance? best regards and thanks, grant
Thanks for the links! About 'simplistic design' , well, err, I'm not totally certain as to what aspect of xo design you're referring to? But I'll go back over your previous posts and try to figure it out!
Unfortunately, still , some of your insightful advice goes way over my head, but I like to persevere as best I can, and will follow up your links. I briefly looked at your 'mhsoft' link, but, at the time, didn't know
how to use it. So my next question might be erroneous...
Would heat generated from a higher DCR coil degrade performance? best regards and thanks, grant
Hi,
There are a lot of simplistic calculators on that page.
Regarding inductor / resistor heating and voice coil heating its all a
question of time constants. I'm not advocating using 4R inductors,
just saying very low DCR inductors may not be cost effective, and
in some crossover positions fairly pointless due to the low power.
🙂/sreten.
There are a lot of simplistic calculators on that page.
Regarding inductor / resistor heating and voice coil heating its all a
question of time constants. I'm not advocating using 4R inductors,
just saying very low DCR inductors may not be cost effective, and
in some crossover positions fairly pointless due to the low power.
🙂/sreten.
- Status
- Not open for further replies.