So I've built some cheapo party / garage speakers! Cheap, big, and loud were the design goals, and after hearing the woofer run full range I think I'm on the road to success. The box is together, but I still need the crossover. So here I am looking for help. 😀
Here's what I got:
A big, cheap, MCM 12" part no. 55-1745
12'' Professional Woofer | MCM Audio Select | 55-1745 (551745)
Claims response out to 4.5 khz
Cheapish Pyle compression driver
Tweeter Titanium Horn Driver Threaded Compression 150w RMS | Pyle | PDS221
Fs 800 hz (claimed)
I haven't found any frequency response graphs for these inexpensive drivers. I don't have frequency response measuring stuff, though I can do an impedance sweep.
Dayton 10" waveguide for the pyle
Parts-Express.com:*Dayton H10RW 10" Round Waveguide 1" Threaded | horn lens horn tweeter horn bell horn compression driver DaytonAudioWaveguides070109
loads down to 1,600 hz.
My simplistic plan at this point is to hear from some one what kind of acoustic slope is going to come out of the tweeter / WG combo, then add maybe 2nd order electrical (prolly around that 1.6 khz from the WG) to keep me from toasting the tweeters. Then whatever would match that on the woofer. Plus impedance compensation. BSC will be considered after the woofer and tweeter are playing nicely together.
But this is the first pair of speakers I've built w/o someone else's plan to follow, so maybe someone else will have a better idea. Whadya think?
Here's what I got:
A big, cheap, MCM 12" part no. 55-1745
12'' Professional Woofer | MCM Audio Select | 55-1745 (551745)
Claims response out to 4.5 khz
Cheapish Pyle compression driver
Tweeter Titanium Horn Driver Threaded Compression 150w RMS | Pyle | PDS221
Fs 800 hz (claimed)
I haven't found any frequency response graphs for these inexpensive drivers. I don't have frequency response measuring stuff, though I can do an impedance sweep.
Dayton 10" waveguide for the pyle
Parts-Express.com:*Dayton H10RW 10" Round Waveguide 1" Threaded | horn lens horn tweeter horn bell horn compression driver DaytonAudioWaveguides070109
loads down to 1,600 hz.
My simplistic plan at this point is to hear from some one what kind of acoustic slope is going to come out of the tweeter / WG combo, then add maybe 2nd order electrical (prolly around that 1.6 khz from the WG) to keep me from toasting the tweeters. Then whatever would match that on the woofer. Plus impedance compensation. BSC will be considered after the woofer and tweeter are playing nicely together.
But this is the first pair of speakers I've built w/o someone else's plan to follow, so maybe someone else will have a better idea. Whadya think?
Attachments
To stay in the spirit of the project (cheapish, simplistic, no data available), I would just put a capacitor in front of the compression driver to protect it. Any value between 6 and 8uF will probably do the trick (a 63V electrolytic is the cheapishest one can find). The compression will most probably play too loud compared to the woofer so you will probably want to add a resistor before the capacitor; depending on taste, something between 2 to 8 ohms should do (10W if you listen musik gently, 20W or more if you do parties).
Chris.
Chris.
Thanks for the response! I had just about figured this post for ignored.
I was just slapping some poly on them this weekend, to keep the OSB from getting mushy if the garage gets a little damp. I must say that the 12-inch (running full range ATM) is great fun. Rarely misbehaved, and it has great impact, tho I'll have to finish the speaker before I can give it an unrestrained thumbs up. In the box I made I think the predicted f3 is just a bit under 50 hz. Some people think the xmax spec is a typo (according to a post over at BillFitzmaurice that no longer exists, but google still returns it, so grain of salt). I know the driver takes everything my little cheapy 15 watt garage amp can throw at it on bassy music as if it were nothing.
Here's the thing, tho: the 12" is (as one might expect) real directional by the top of it's frequency range. Moving even a little bit off axis during test listening sounds like a blanket is thrown over it. So I was wanted to cross the tweeter in lower so that the party people can still hear the treble when they move off axis. I was thinking of the 2khz neighborhood.
Sound reasonable? Or am I getting too complex?
Thanks again for the input!
I was just slapping some poly on them this weekend, to keep the OSB from getting mushy if the garage gets a little damp. I must say that the 12-inch (running full range ATM) is great fun. Rarely misbehaved, and it has great impact, tho I'll have to finish the speaker before I can give it an unrestrained thumbs up. In the box I made I think the predicted f3 is just a bit under 50 hz. Some people think the xmax spec is a typo (according to a post over at BillFitzmaurice that no longer exists, but google still returns it, so grain of salt). I know the driver takes everything my little cheapy 15 watt garage amp can throw at it on bassy music as if it were nothing.
Here's the thing, tho: the 12" is (as one might expect) real directional by the top of it's frequency range. Moving even a little bit off axis during test listening sounds like a blanket is thrown over it. So I was wanted to cross the tweeter in lower so that the party people can still hear the treble when they move off axis. I was thinking of the 2khz neighborhood.
Sound reasonable? Or am I getting too complex?
Thanks again for the input!
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That would be expected from a woofer like that - they'll go reasonably high, so you think "brilliant, I can cross that high", then you learn it beams. I'd try to find out where the beaming starts getting worse, then XO there.
For the Xmax, this could well be correct. It is, after all a music speaker, generally speaking (what I've read), they have low Xmax, but decent Xmech. The non-linear starts early, but you don't notice it until it's really far out. For example, I got a woofer with 3mm Xmax, goes to 12mm p/p then bottoms out. Sounds fine anywhere between.
For the Xmax, this could well be correct. It is, after all a music speaker, generally speaking (what I've read), they have low Xmax, but decent Xmech. The non-linear starts early, but you don't notice it until it's really far out. For example, I got a woofer with 3mm Xmax, goes to 12mm p/p then bottoms out. Sounds fine anywhere between.
Really like this project idea. If yours turns out well, i might have to try building a pair of my own.
I would like to second what chris said about the X-max. I have most of my experience with subwoofers (where distortion is less audible), but many of those drivers have the capability to far exceed their given xmax without issues. And given the size of that woofer and by the look of the surround, i would think its be capable of over 1mm of excursion without problems
good luck continuing the build
I would like to second what chris said about the X-max. I have most of my experience with subwoofers (where distortion is less audible), but many of those drivers have the capability to far exceed their given xmax without issues. And given the size of that woofer and by the look of the surround, i would think its be capable of over 1mm of excursion without problems
good luck continuing the build
Should be ok for garage functions...
Lower xover only with a second/third order xover. Testing that low 1st order, maintain power low on the CD because of low frequencies and burn out.
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Well it took a little while to get it together, but now it's done: Simple 2nd order LR at 2khz. Based on this site, 2-Way Crossover Designer / Calculator and assuming that the woofer and tweeter were both simple 8r. Also, an L-pad to bring the tweeter in line with the woofer.
And it doesn't sound bad!
Initially I hooked up the tweeter out of phase with the woofer, b/c I had heard that the cross would shift the phase far enough to justify it. But perhaps I heard wrong, or maybe the physical shift from the wave guide was enough to change the phase relationship. Either way, the drivers sound best in phase.
Based on the driver params I measured WinISD suggested a truly gargantuan box. Maybe because I scaled things down some, or maybe b/c I haven't built in any BSC the setup sounded a bit on the lean side. The XTRA-MEGA-BASS button on the garage portable cd player fixed that, though.
I'll probably play with some BSC (have to figure out how to sim it, so I know where to put it), I've heard the wave guide can use some damping and I'm pretty sure the woofer could as well, and probably a little extra work on the XO might render some benefit. Apart from the BSC, though, the speaker is really already about as refined as my garage can justify.
AND they'll go loud enough to rock the garage on just 15 watts. Dynamic and forceful.
If you decide to try something similar, get on MCM's mailing list and keep an eye out for the woofer for a while. They go on sale for $25 / woofer pretty often. At that price it's pretty easy to call them a bargain.
I'll try to measure out and post what my Lpad settings were, as the l-pads were a significant expenditure in this cheapo project.
And it doesn't sound bad!
Initially I hooked up the tweeter out of phase with the woofer, b/c I had heard that the cross would shift the phase far enough to justify it. But perhaps I heard wrong, or maybe the physical shift from the wave guide was enough to change the phase relationship. Either way, the drivers sound best in phase.
Based on the driver params I measured WinISD suggested a truly gargantuan box. Maybe because I scaled things down some, or maybe b/c I haven't built in any BSC the setup sounded a bit on the lean side. The XTRA-MEGA-BASS button on the garage portable cd player fixed that, though.
I'll probably play with some BSC (have to figure out how to sim it, so I know where to put it), I've heard the wave guide can use some damping and I'm pretty sure the woofer could as well, and probably a little extra work on the XO might render some benefit. Apart from the BSC, though, the speaker is really already about as refined as my garage can justify.
AND they'll go loud enough to rock the garage on just 15 watts. Dynamic and forceful.
If you decide to try something similar, get on MCM's mailing list and keep an eye out for the woofer for a while. They go on sale for $25 / woofer pretty often. At that price it's pretty easy to call them a bargain.
I'll try to measure out and post what my Lpad settings were, as the l-pads were a significant expenditure in this cheapo project.
This type of driver is intended for guitar type applications and has a suspension that increases in stiffness very rapidly from the rest position, this is to resist the very large d.c. pulsing effect you from playing bar chords for instance.
In essence it is designed to produce and not reproduce music, distortion is part of its sound.
A better option is to use a driver such as a coax intended for fold back monitors, these have a larger linear excursion and a curved cone to smooth out the midrange.
rcw.
In essence it is designed to produce and not reproduce music, distortion is part of its sound.
A better option is to use a driver such as a coax intended for fold back monitors, these have a larger linear excursion and a curved cone to smooth out the midrange.
rcw.
Is it just the X-max that tips you off that it's a guitar driver, or is there some other aspect?
The MCM site for the driver lists musical insturment as an application, but also PA and sound reinforcement. Then it compares the driver to an Eminence Alpha, and those get used in some Pi Speakers setups. So that's why I bought 'em.
Having listened to the driver, I can say that it is sufficiently well-behaved for garage and back yard duty. The sound quality requirements here are not particularly stringent.
The MCM site for the driver lists musical insturment as an application, but also PA and sound reinforcement. Then it compares the driver to an Eminence Alpha, and those get used in some Pi Speakers setups. So that's why I bought 'em.
Having listened to the driver, I can say that it is sufficiently well-behaved for garage and back yard duty. The sound quality requirements here are not particularly stringent.
How about that box it's in?
Well, I've been moving ahead on these speakers. I thought I'd drop in here and post more about what I've done.
For one thing, I thought I'd talk about the box design for a moment, since I haven't posted anything.
I measured the drivers with a Dayton WT3. I have 2 drivers, and measured each one 3 times. Here's the average I came up with, for anyone who wonders about the spec on the 12" MCM 55-1745.
SPL - 97.8 db
re - 7.571 ohm
fs - 46.43 hz
qts - .438
qes - .466
qms - 7.359
le - .632 mH
mms - 27.06 g
vas - 6.02 ft^3
This went into WinISD for box design. The Efficiency Bandwidth Product came up as 102.2, pointing fairly clearly to a vented box. WinISD said I could get an F3 of 40 hz, and all I'd need was an 8 cuft box! I downsized to 5.8 cuft and ended up with an F3 of 46 hz. It's tuned to 43 hz.
The box itself is internally 12.5 x 17.66 x 47.5, or externally 14 x 19.16 x 49. The port uses the internal width of the box, coming in at 12.5 x 2.875 tall by 3.41 deep. The raw box volume is 10427 cu in, minus the extra junk I put in about 10051 cu in. (all dimensions inches)
Next: about that filter...
Well, I've been moving ahead on these speakers. I thought I'd drop in here and post more about what I've done.
For one thing, I thought I'd talk about the box design for a moment, since I haven't posted anything.
I measured the drivers with a Dayton WT3. I have 2 drivers, and measured each one 3 times. Here's the average I came up with, for anyone who wonders about the spec on the 12" MCM 55-1745.
SPL - 97.8 db
re - 7.571 ohm
fs - 46.43 hz
qts - .438
qes - .466
qms - 7.359
le - .632 mH
mms - 27.06 g
vas - 6.02 ft^3
This went into WinISD for box design. The Efficiency Bandwidth Product came up as 102.2, pointing fairly clearly to a vented box. WinISD said I could get an F3 of 40 hz, and all I'd need was an 8 cuft box! I downsized to 5.8 cuft and ended up with an F3 of 46 hz. It's tuned to 43 hz.
The box itself is internally 12.5 x 17.66 x 47.5, or externally 14 x 19.16 x 49. The port uses the internal width of the box, coming in at 12.5 x 2.875 tall by 3.41 deep. The raw box volume is 10427 cu in, minus the extra junk I put in about 10051 cu in. (all dimensions inches)
Next: about that filter...
annnd the filter
So once I had it all together I had to get the woofer and the tweeter playing nice. As I said earlier, a simple LR2 at 2khz is what I implemented, with the naive assumption that both woofer and tweeter were 8 ohms. It didn't turn out too bad in the crossover region. I was prepared for it to kinda suck, but it's listenable.
It didn't have any bass to speak of, though. So I decided to have a look at The Edge baffle diffraction simulator and see what was happening, theoretically. It seems there's a wideish hump from about 300 to 1 khz, and below that it drops steadily. 3 or 4 db down by 100 hz, another couple on top of that by 70 hz. The Edge suggested a BSC of 7.43 mH and 8 ohms. What I had in my parts bin, however, was 9.1 mH. Once I jiggered the Edge to work with that value, it said 10 ohms would go best with it, so I ran out to Rat Shack and picked up a couple of big resistors to do the job. This helped a lot! Much more even than hitting the bass boost on the garage diskman. Now we're really getting somewhere, I can jam to this.
I listened for a few days and I started to feel like the upper high-end was missing. Does the PE waveguide count as a constant directivity horn? I've learned that they need some HF lift. Additionally, MINIRIG has a review on the PE sight that includes a link, and after nosing around there it looked like there was evidence that he had some HF droop going on as well. So at the moment I've got the BSC bypassed by a 2.25 uf capacitor to try and bring the HF back up. I think this would be about 10 khz. I'll have to listen for a few days and try a few different values to decide what is really best, but I think this helped.
Who knows how far I'll go with the cross, if each thing that's wrong obscures another issue, like nested russian dolls. There might be lots of stuff to think about. But they're only garage speakers.
So once I had it all together I had to get the woofer and the tweeter playing nice. As I said earlier, a simple LR2 at 2khz is what I implemented, with the naive assumption that both woofer and tweeter were 8 ohms. It didn't turn out too bad in the crossover region. I was prepared for it to kinda suck, but it's listenable.
It didn't have any bass to speak of, though. So I decided to have a look at The Edge baffle diffraction simulator and see what was happening, theoretically. It seems there's a wideish hump from about 300 to 1 khz, and below that it drops steadily. 3 or 4 db down by 100 hz, another couple on top of that by 70 hz. The Edge suggested a BSC of 7.43 mH and 8 ohms. What I had in my parts bin, however, was 9.1 mH. Once I jiggered the Edge to work with that value, it said 10 ohms would go best with it, so I ran out to Rat Shack and picked up a couple of big resistors to do the job. This helped a lot! Much more even than hitting the bass boost on the garage diskman. Now we're really getting somewhere, I can jam to this.
I listened for a few days and I started to feel like the upper high-end was missing. Does the PE waveguide count as a constant directivity horn? I've learned that they need some HF lift. Additionally, MINIRIG has a review on the PE sight that includes a link, and after nosing around there it looked like there was evidence that he had some HF droop going on as well. So at the moment I've got the BSC bypassed by a 2.25 uf capacitor to try and bring the HF back up. I think this would be about 10 khz. I'll have to listen for a few days and try a few different values to decide what is really best, but I think this helped.
Who knows how far I'll go with the cross, if each thing that's wrong obscures another issue, like nested russian dolls. There might be lots of stuff to think about. But they're only garage speakers.
A few words about the sound
So do the woofers sound unusably distorted? no. Running them unfiltered seems to point at a fairly mild rolloff, not some crazy high-order distortion freakout. As a system the two drivers together don't compare to my living room system, but they're at least as good as my factory automobile system.
And they go loud like it ain't no thang. I was playing them the other night when I was working on a different project. I was rocking out, and then I powered up the table saw. The speakers handily overpowered the table saw, and they did so with enough aplomb that I happened to actually be listening at that volume anyway. They were also able to play in my garage loud enough that I could listen to them in the back yard. I had to turn it up so I could hear the music over the jets that fly over head (on the runway approach). They had no difficulty with it. This with a 15 watt amp, mind.
I was able to make them lose it with some bassy music with the bass boost dialed all the way up. Then things got pretty ugly. These are tuned to 43 hz, and a lot of content below that will drive 'em past xmax. I don't think I was in any danger of hurting the drivers, they just started to sound farty, is all. If you wanna get crazy, an active cross to a sub at 60 or 70 hz would bring these to a new level of volume, I'm sure. These have the sound I was looking for - that drunk-on-power sense of limitless dynamic capacity. They make turning it up fun for a long time before they start to give.
I may refine a few bits of XO here or there, but overall I'm happy with what I've made. As this project was about big, cheesy, and powerful, I've named the speakers The Thundercats. 😀
Maybe I'll stencil a big Thundercats logo on the sides of 'em. 😎
So do the woofers sound unusably distorted? no. Running them unfiltered seems to point at a fairly mild rolloff, not some crazy high-order distortion freakout. As a system the two drivers together don't compare to my living room system, but they're at least as good as my factory automobile system.
And they go loud like it ain't no thang. I was playing them the other night when I was working on a different project. I was rocking out, and then I powered up the table saw. The speakers handily overpowered the table saw, and they did so with enough aplomb that I happened to actually be listening at that volume anyway. They were also able to play in my garage loud enough that I could listen to them in the back yard. I had to turn it up so I could hear the music over the jets that fly over head (on the runway approach). They had no difficulty with it. This with a 15 watt amp, mind.
I was able to make them lose it with some bassy music with the bass boost dialed all the way up. Then things got pretty ugly. These are tuned to 43 hz, and a lot of content below that will drive 'em past xmax. I don't think I was in any danger of hurting the drivers, they just started to sound farty, is all. If you wanna get crazy, an active cross to a sub at 60 or 70 hz would bring these to a new level of volume, I'm sure. These have the sound I was looking for - that drunk-on-power sense of limitless dynamic capacity. They make turning it up fun for a long time before they start to give.
I may refine a few bits of XO here or there, but overall I'm happy with what I've made. As this project was about big, cheesy, and powerful, I've named the speakers The Thundercats. 😀
Maybe I'll stencil a big Thundercats logo on the sides of 'em. 😎
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This type of driver is made to go down to 80Hz. and achieves its maximum performance in a QB5 II type of filter assisted alignment.
If you model this in win isd the box is 80 litres tuned to 60Hz. with a q=.5, 60Hz. electronic filter.
Over this range it can produce average sound levels of 116db. without exceeding 3mm. peak cone excursion, this is what it is intended to do.
Cheap p.a. type drivers of this sort also generally use cone breakup to increase apparent loudness, this also gives it the required guitar type formant for instrument use.
As I have pointed out in another thread the so called professional drivers are in general intended for specific purposes such as I outlined, and to be rugged enough not to fall apart when performing that purpose. Fidelity for the reproduction of music is not required.
You can get pro drivers that reproduce music well, (used in fold-back monitors), but they are generally not in the price class of this driver.
rcw.
If you model this in win isd the box is 80 litres tuned to 60Hz. with a q=.5, 60Hz. electronic filter.
Over this range it can produce average sound levels of 116db. without exceeding 3mm. peak cone excursion, this is what it is intended to do.
Cheap p.a. type drivers of this sort also generally use cone breakup to increase apparent loudness, this also gives it the required guitar type formant for instrument use.
As I have pointed out in another thread the so called professional drivers are in general intended for specific purposes such as I outlined, and to be rugged enough not to fall apart when performing that purpose. Fidelity for the reproduction of music is not required.
You can get pro drivers that reproduce music well, (used in fold-back monitors), but they are generally not in the price class of this driver.
rcw.
Mr. White, I presume?
rcw - thanks for your input! I googled your QB5 reference and found this article - Satellites and Subwoofers I'll assume for the rest of this post that this link is both correct and what you happen to be talking about.
I had thought I was doing my best to limit excursion with a simple ported box, though I see how one might limit it even further with this scheme. The article I found compares the QB5 alignment with the sealed box, would you care to comment on how it compares to a ported box? After following the math in the article (for this driver), it appears that you get a 2 db hump vs a ported box. The boost is much greater than a that of a sealed box, but is 2 db really that much of a savings? And this in significantly larger box than I was hoping for. Perhaps I am not relating the hump size appropriately to the resulting benefit.
Speaking of following the math, based on the PG17wg-00-08 example in the linked article, I came up with some different numbers that you listed. I measured a driver Qts of ~.44, so based on the Qts .44 entry first in group 2, I see Vas/Vb = .55. Since I have 6.02 cuft for the MCM, I get a Vb = Vas / .55 = 10.96 cuft, or 310 liters. Cutoff = box tuning = filter frequency = 47.6 hz. 310 L is significantly different than 80.
Have I misunderstood the application, or did you make a design choice I'm unaware of? For the alignment you quote is cutoff still equal to tuning frequency? Do these designs unload beneath tuning like regular ported boxes, or does the filter ameliorate that?
Is such a setup appropriate for any driver within the Qts of the charts? Aside from PA setups I could see it being valuable for anyone working with a low xmax driver.
Perhaps there is more information about the alignment that I have not yet found...
Regarding cone breakup - I expect breakup in a cone of this size that claims extension out as far as it does. I had hoped to cut it out (to an extent) with my 2khz XO. Do you have a frequency range you would expect this breakup to be in? I was considering a PVA glue treatment for the woofer - mostly for moisture resistance, but it might help damp a breakup. What do you think?
I recognize that this driver is not an optimal choice. I'd like to get the best quality of output from it that I can, but it is what it is. As someone who is at least as interested in the building as I am in the owning, I'm trying to learn and build as much as I can per dollar, and that means using cheap drivers. Perhaps if I get pleasant enough sounds from this exercise I'll try an up-market version.
Thanks again for pointing out this QB5 alignment, and for whatever thoughts you may have in response.
Figure: yellow = WinISD suggested sealed box, Lt. Blue = WinISD suggested ported, Green = my QB5, Orange = rcw suggested QB5 (unfiltered)
rcw - thanks for your input! I googled your QB5 reference and found this article - Satellites and Subwoofers I'll assume for the rest of this post that this link is both correct and what you happen to be talking about.
I had thought I was doing my best to limit excursion with a simple ported box, though I see how one might limit it even further with this scheme. The article I found compares the QB5 alignment with the sealed box, would you care to comment on how it compares to a ported box? After following the math in the article (for this driver), it appears that you get a 2 db hump vs a ported box. The boost is much greater than a that of a sealed box, but is 2 db really that much of a savings? And this in significantly larger box than I was hoping for. Perhaps I am not relating the hump size appropriately to the resulting benefit.
Speaking of following the math, based on the PG17wg-00-08 example in the linked article, I came up with some different numbers that you listed. I measured a driver Qts of ~.44, so based on the Qts .44 entry first in group 2, I see Vas/Vb = .55. Since I have 6.02 cuft for the MCM, I get a Vb = Vas / .55 = 10.96 cuft, or 310 liters. Cutoff = box tuning = filter frequency = 47.6 hz. 310 L is significantly different than 80.
Have I misunderstood the application, or did you make a design choice I'm unaware of? For the alignment you quote is cutoff still equal to tuning frequency? Do these designs unload beneath tuning like regular ported boxes, or does the filter ameliorate that?
Is such a setup appropriate for any driver within the Qts of the charts? Aside from PA setups I could see it being valuable for anyone working with a low xmax driver.
Perhaps there is more information about the alignment that I have not yet found...
Regarding cone breakup - I expect breakup in a cone of this size that claims extension out as far as it does. I had hoped to cut it out (to an extent) with my 2khz XO. Do you have a frequency range you would expect this breakup to be in? I was considering a PVA glue treatment for the woofer - mostly for moisture resistance, but it might help damp a breakup. What do you think?
I recognize that this driver is not an optimal choice. I'd like to get the best quality of output from it that I can, but it is what it is. As someone who is at least as interested in the building as I am in the owning, I'm trying to learn and build as much as I can per dollar, and that means using cheap drivers. Perhaps if I get pleasant enough sounds from this exercise I'll try an up-market version.
Thanks again for pointing out this QB5 alignment, and for whatever thoughts you may have in response.
Figure: yellow = WinISD suggested sealed box, Lt. Blue = WinISD suggested ported, Green = my QB5, Orange = rcw suggested QB5 (unfiltered)
Attachments
The point about the QB5 II type alignments is that depending upon the drivers parameters and the required cut off, they can give an average of 12db. more output for the same cone excursion, they do this because they have optimum coupling between the Helmholtz resonator and the driver.
What this means in the p.a. context is that you can optimise the output from the driver because you can use both the full linear cone excursion and the voice coil dissipation capacity, this allows you to get the most sound from the least space. Typical domestic systems are excursion limited, and generally give the most bass extension from the least space, a different design goal.
For music on a p.a. it is usual to leave the hump in the unfiltered QB5 II, and this gives punch region bass, in this case it is usual to use a high pass filter about an octave lower to reduce low frequency cone excursion.
Twelve inch cones of this sort usually have a break up induced rise starting from around 1.5kHz.
If you look at the cone excursion you will see that for the QB5 both the low and high peaks are about the same.
It states in the ads. that this driver is suitable for bass guitar. This means that it has a suspension that becomes gradually stiffer with excursion.
When reproducing music this produces large amounts of odd harmonics at larger excursions, these generally sound bad, but the suspension is designed to withstand the d.c. pulsing effect you get with bass guitars, and to reproduced music a punch peak and low excursion, (but still loud enough because of the optimised coupling to the reflex box).
You get the figures I mentioned by compliance scaling the alignment, there is also an article about that.
rcw.
What this means in the p.a. context is that you can optimise the output from the driver because you can use both the full linear cone excursion and the voice coil dissipation capacity, this allows you to get the most sound from the least space. Typical domestic systems are excursion limited, and generally give the most bass extension from the least space, a different design goal.
For music on a p.a. it is usual to leave the hump in the unfiltered QB5 II, and this gives punch region bass, in this case it is usual to use a high pass filter about an octave lower to reduce low frequency cone excursion.
Twelve inch cones of this sort usually have a break up induced rise starting from around 1.5kHz.
If you look at the cone excursion you will see that for the QB5 both the low and high peaks are about the same.
It states in the ads. that this driver is suitable for bass guitar. This means that it has a suspension that becomes gradually stiffer with excursion.
When reproducing music this produces large amounts of odd harmonics at larger excursions, these generally sound bad, but the suspension is designed to withstand the d.c. pulsing effect you get with bass guitars, and to reproduced music a punch peak and low excursion, (but still loud enough because of the optimised coupling to the reflex box).
You get the figures I mentioned by compliance scaling the alignment, there is also an article about that.
rcw.
Hi,
I'm also working on a project using the Pyle PDS221 compression drivers. In fact the graphs Col (Minirig ) posted were probably ones I made, though I cant see them on the PE site any more.
I'm attempting some "econowave" style speakers (but I think I'll call them cheapowave? as the Pyle PDS221 is at a much cheaper pricepoint than the Selenium driver used in the econowave project, though I'm using a Pyle PH612 horn).
Project has been slow going as I've been busy with other stuff and on a steep learning curve, but just about to get to grips with the design crossover phase of mine.
I'm also working on a project using the Pyle PDS221 compression drivers. In fact the graphs Col (Minirig ) posted were probably ones I made, though I cant see them on the PE site any more.
I'm attempting some "econowave" style speakers (but I think I'll call them cheapowave? as the Pyle PDS221 is at a much cheaper pricepoint than the Selenium driver used in the econowave project, though I'm using a Pyle PH612 horn).
Project has been slow going as I've been busy with other stuff and on a steep learning curve, but just about to get to grips with the design crossover phase of mine.
Zog, those sure look like some big fun. What woofer are you using?
The stuff from col minirig that I saw was actually referenced off the 10" dayton waveguide page from PE. That link turned out to be no-worky, by I was able to stumble my way over to this one: dsc01523 among others... So the stuff I saw there related to the waveguide, not the Pyle drivers. If you've got some measurements for those I hope you'll consider posting them.
I considered trying to ape the econowave crossover, but since my tweeter and horn were both different I figured it was a 50/50 gamble at best. If you have further details about your project I'd be interested to follow it. Nice to see someone with a similar build concept.
I won't be sawing any more wood this season... -7 f, (-21 c) tonight is too cold to be waving numb fingers around a tablesaw. But I'll try to figure out that compliance scaling article (Loudspeaker Compliance Scaling) and perhaps it'll see some application come spring thaw.
The stuff from col minirig that I saw was actually referenced off the 10" dayton waveguide page from PE. That link turned out to be no-worky, by I was able to stumble my way over to this one: dsc01523 among others... So the stuff I saw there related to the waveguide, not the Pyle drivers. If you've got some measurements for those I hope you'll consider posting them.
I considered trying to ape the econowave crossover, but since my tweeter and horn were both different I figured it was a 50/50 gamble at best. If you have further details about your project I'd be interested to follow it. Nice to see someone with a similar build concept.
I won't be sawing any more wood this season... -7 f, (-21 c) tonight is too cold to be waving numb fingers around a tablesaw. But I'll try to figure out that compliance scaling article (Loudspeaker Compliance Scaling) and perhaps it'll see some application come spring thaw.
Hi,
I am using Pioneer A30GC50-52F-Q-1 woofers sourced from Ebay.
I have a rough ARTA freq response curve of the Pyle pds221 plus Pyle PH612 horn here (with 15 uF protection cap and a 9dB LPAD):
Though I will be repeating these measurements more carefully tonight now I am feeling more comfortable with the measurement software, etc, that graph is quite rough but the pds221 does look like it will need a notch filter to get squash that bump.
Supposed to be hitting 39 c here tomorrow.. I'll find a coping mechanism (beer!) though.
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Hi Adam, Zog,
The review I did in PE was for the Dayton 10" conical waveguide (same as the one adam is using). Adam, it's worth building the back of those guides up with some car body filler. They are a bit on the thin side. Also, careful with over-tightening the screws the plastic cracks!
col.
The review I did in PE was for the Dayton 10" conical waveguide (same as the one adam is using). Adam, it's worth building the back of those guides up with some car body filler. They are a bit on the thin side. Also, careful with over-tightening the screws the plastic cracks!
col.