For readers who may not already be aware- @augerpro covered many of them in his huge study dedicated solely to cabinet construction:
https://www.somasonus.net/box-construction-methods
Buy the man a coffee!:
https://www.gofundme.com/f/a-monster-box-construction-project
You da man, Thanh!
This issue does raise a question in my mind about whether driver isolation methods, like the one I tested, would do more harm than good if the driver is operating at lower frequencies.
And of course, not everything that can be measured matters, and not everything that matters can be measured.
But your study gave me hints to where the problem may lie, as shown in post #1771.
I have another driver that shall remain nameless for now. A quick and dirty measurement shows this:
But I'm confident I can get rid of that pesky thing around 300Hz without negatively affecting something else.
?lack of chamfer to allow driver to breathe. (rear ventilation limited due to massive size of magnet)
?lack of dampers behind screws or frame
But your study gave me hints to where the problem may lie, as shown in post #1771.
I have another driver that shall remain nameless for now. A quick and dirty measurement shows this:
But I'm confident I can get rid of that pesky thing around 300Hz without negatively affecting something else.
?lack of chamfer to allow driver to breathe. (rear ventilation limited due to massive size of magnet)
?lack of dampers behind screws or frame
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Well, I guess I can officially join this thread, having now received my 2x 6.5X04-NAA woofers. Gorgeous drivers; I know not everyone is a fan of the surround appearance, but I very much am. To me, it looks similar to the 'alien' shapes that come out of generative design processes.
I will be using these as midwoofers in a 3-way system, driven and crossed over by a hypex fusion amp.
On the top end will be a waveguided tweeter. I have several on hand that would work, SB26CDC, Wavecor tw030, and Peerless DA25TX (if I can find a suitably well-developed guide) are the leading contenders. I will likely build this is such a way that I can swap them out and compare.
On the bottom end will be suitably high-quality subwoofers. Again, several on hand. Currently deciding between Dayton RSS315HF04, Rhythmik servosubs (with the older, TC-sourced aluminum drivers), or even a pair of these B&W Rohacell woofers I have been holding in reserve. Most likely I will use the Rhythmiks, as they are already built and have served me well so far.
Currently, my thinking as to general approach is:
I will be using these as midwoofers in a 3-way system, driven and crossed over by a hypex fusion amp.
On the top end will be a waveguided tweeter. I have several on hand that would work, SB26CDC, Wavecor tw030, and Peerless DA25TX (if I can find a suitably well-developed guide) are the leading contenders. I will likely build this is such a way that I can swap them out and compare.
On the bottom end will be suitably high-quality subwoofers. Again, several on hand. Currently deciding between Dayton RSS315HF04, Rhythmik servosubs (with the older, TC-sourced aluminum drivers), or even a pair of these B&W Rohacell woofers I have been holding in reserve. Most likely I will use the Rhythmiks, as they are already built and have served me well so far.
Currently, my thinking as to general approach is:
- I am not going to make full use of the purifi's low end, aiming instead to use them as a very wideband mid that can reach low. So I will most likely use the 6.5X04-NAA sealed, maybe aiming for QTC=0.577 or 0.6 enclosure
- to cross to the subs somewhere under 120hz, primarily to relieve the purifis of the lowest bass where they will begin to be excursion limited.
- to cross relatively shallow to the WG-supported tweeter wherever the best directivity match can be found.
Before cutting off the low end of the purifis, maybe try running them with the subs first. At that low of frequency, your room will inevitably have lots of nodes that even two subs won't completely fill in. And I don't think you'll have to worry about a sealed purifi reaching it's excursion limit. They will likely have much less distortion at those frequencies than any sub you'll build yourself.Well, I guess I can officially join this thread, having now received my 2x 6.5X04-NAA woofers. Gorgeous drivers; I know not everyone is a fan of the surround appearance, but I very much am. To me, it looks similar to the 'alien' shapes that come out of generative design processes.
I will be using these as midwoofers in a 3-way system, driven and crossed over by a hypex fusion amp.
On the top end will be a waveguided tweeter. I have several on hand that would work, SB26CDC, Wavecor tw030, and Peerless DA25TX (if I can find a suitably well-developed guide) are the leading contenders. I will likely build this is such a way that I can swap them out and compare.
On the bottom end will be suitably high-quality subwoofers. Again, several on hand. Currently deciding between Dayton RSS315HF04, Rhythmik servosubs (with the older, TC-sourced aluminum drivers), or even a pair of these B&W Rohacell woofers I have been holding in reserve. Most likely I will use the Rhythmiks, as they are already built and have served me well so far.
Currently, my thinking as to general approach is:
The purifis are a stretch for me budgetarily, but IMO represent enough of a jump in performance over what's out there to be worth the investment. I have a lot of flexibility in terms of box size/DSP/fabrication methods available, and commensurate to the driver cost and time investment, I am going to try to wring as much performance as I can out of the purifis. I am sure I will be posting more to this thread along those lines soon
- I am not going to make full use of the purifi's low end, aiming instead to use them as a very wideband mid that can reach low. So I will most likely use the 6.5X04-NAA sealed, maybe aiming for QTC=0.577 or 0.6 enclosure
- to cross to the subs somewhere under 120hz, primarily to relieve the purifis of the lowest bass where they will begin to be excursion limited.
- to cross relatively shallow to the WG-supported tweeter wherever the best directivity match can be found.
Also, I assume you're running the subs in separate enclosures?
Why haven't you chose PTT6.5M04-NFA-01 which is a dedicaded mid-range driver?
The 'subs' should really be thought of as bass-bins I suppose. Yes they are separate enclosures, and will most likely serve as stands. I'm not sure I get your point about room nodes; the purifis are just as susceptible to nodes below schroedinger frequency as any other (sub)woofer. If you meant they would smooth out the nodes by being in a different place, that would be different, but since they will be co-located, not likely to be much help there.
In terms of reaching it's excursion limit; if you've modeled a low qtc enclosure with this driver and found you would not run into the excursion limits, more power to you. In my case I have, and I likely would. Nevertheless, I will try letting it roll of naturally, and EQing the sub's low-pass to sum flat, it will be easy to test various configurations in DSP.
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Because I don't need the sensitivity, and that seems to be the main advantage over the x04-NAA. I've carefully read both Yevgeniy and Erin's measurements, and the M04-NFA is a great midrange, on all metrics, through the 150-3k band. But, so is the X04-NAA. However, the X04-NAA is likely the best 6.5" woofer on the market, on top of that midrange performance. That makes it more flexible and versatile for future re-use or re-sale IMO. Also, I prefer metal to paper cones in most instances.
If I were designing a passive speaker, or had negative history with metal mids, it might be a different calculation.
And if I could afford to buy an entirely new set of drivers/crossovers parts, rather than only buying the X04-NAA, I would surely just build Jon Marsh's design as tktran suggested when I asked the very same question - I have great respect and admiration for his work, and his Modula MTs have served in my living room with honour for many years now
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In a three way the choice is simple, isolate/decouple the mid and leave the woofer alone. If the speaker is both a mid and a woofer you are picking your poison.
https://www.diyaudio.com/community/threads/how-to-brace-a-speaker-cabinet.235908/post-4210469
https://www.diyaudio.com/community/threads/how-to-brace-a-speaker-cabinet.235908/post-4191876
I agree with you which is why I bought the same driver
When the resonances are notched the Aluminium 6.5" driver is better behaved and smoother than any other Purifi driver.
And if I could afford to buy an entirely new set of drivers/crossovers parts, rather than only buying the X04-NAA, I would surely just build Jon Marsh's design as tktran suggested when I asked the very same question - I have great respect and admiration for his work, and his Modula MTs have served in my living room with honour for many years now
Here’s my shameless promotion for a non-profit DIY-only family of 2 ways featuring 4-8” X04-NFC and NAA
https://www.diyaudio.com/community/...ts-purifi-and-scan-speak.390316/#post-7123449
A 3 way featuring twin 12” woofers and 6.5M-04 is a real possibility, as I have these drivers on hand. Or another midrange (SPL>=93dB/2.83dB 4 ohm, low distortion and wide dispersion to 3+KHz)
I won’t be drawn into debating about which is best because it’s horses for courses. I may, however, be able to advise what may suit one room over another, or one application over another.
Erin’s measurement of the 6.5X04-NAA in my cabinet, exported to VituixCad2:
1 shelving filter (for baffle step compensation) , 1 notch filter (for the metal cone resonance), 1 LP filter (for crossover) later:
I think this is what fluid refers to as: “When the resonances are notched the Aluminium 6.5" driver is better behaved and smoother than any other Purifi driver”
I’d add- any 6.5” driver…
(Save your money to) buy with confidence!
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Original data of the cabinet mounted PTT6.5X04-NAA, as I discussed above, courtesy of www.erinsaudiocorner.com
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At Kim of Purifi is it possible for you to give miniDSP file with linkwitz transform for a 2 way with 4" purifi woofer In your published plan is passive crossover and I would like to try active hear it forst then spend money on passive. Also miniDSp or Hypex files for other plans too please.
Also if people in this forum are willing to share their projects even at a cost would be open. I have no skills to measure so ...
regards
anand
Also if people in this forum are willing to share their projects even at a cost would be open. I have no skills to measure so ...
regards
anand
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Friends I have 6.5" Purifi woofer pair not the new X and ViaWave ribbon and Peerless corundom tweeters. I wish to make a super powerful stereo system for bass I have various Drivers like Beyma 12BR70 4 nos , Peerless STW 350 2 nos if someone can guide how go about buildig a great system I have minidsp 2x4HD 2 nos and Hypex 502 and 112mp amp modules. I listen to music 10 ft away from speakers room is 15ft wide ceeling is 10ft and depth is 28ft I am a tight basss freak and want to experience till 10hz if possible. I am open to paying for servces too
regards
anand
regards
anand
I've done this exactly as Evgeniy described in a FB post, 20 seconds with a heat gun (low setting) on a copper foil snug to the grille. No issues and no residual heat affecting the driver. Printed his WG design on nylon SLS and it fits perfectly
Ho boy, you got a long way to go.
Are you building cabinets yourself or need someone to design cabinets for you too? May need to start your own thread on this, I'm sure someone is willing to help design if you pay.
That is one insanely flat woofer, post baffle correction. Holy smokes. Got 2 here, chomping to get my new shop set up to get some cabinets done. Did you post baffle size? No worries if you wanna keep that IP
This is the link and there are a few photos in the comments underneath which were quite helpful
https://www.facebook.com/hificompas...bGWEcBe9ntt1g0Ryz2neEjYKxOrF8D1&__tn__=,O,P-R