@otto88
I'd like to see this too. The only working amps I have at the moment are M2x. One thought is it to run four channels, one per driver, two-way. That probably still falls way short but I'd be delighted if it could work. I've heard there is a way to hot-rod the M2 but I've never seen it done. F5 turbo is another match I'd like to see.
Go for class A and tell us about it
I'd like to see this too. The only working amps I have at the moment are M2x. One thought is it to run four channels, one per driver, two-way. That probably still falls way short but I'd be delighted if it could work. I've heard there is a way to hot-rod the M2 but I've never seen it done. F5 turbo is another match I'd like to see.
Go for class A and tell us about it
Yes, I have played the Purifi in a 40w Class A amp. It sounds great and that’s about the minimum amount of power I would recommend for one to fully appreciate its capabilities when driven by a Class A amp. I used Hugh Dean’s Alpha Nirvana amp.
There is a new power JFET choke loaded SE Class A amp I have been working on that puts out 40w called the LuFo amp.
It’s single rail so dual secondaries gives you a dual monoblock amp in a single chassis.
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To power the speakers I built (posted on this thread here), I'm using the March Audio amp that uses the Purifi amplifer module.
These monoblocks produce 450W (and are stable into a 2 ohm load). The system sounds really good and very dynamic with the 2 Purifi drivers in a sealed enclosure.
These monoblocks produce 450W (and are stable into a 2 ohm load). The system sounds really good and very dynamic with the 2 Purifi drivers in a sealed enclosure.
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These monoblocks produce 450W (and are stable into a 2 ohm load). The system sounds really good and very dynamic with the 2 Purifi drivers in a sealed enclosure.
Can you tell a bit more about your implementation? Do you mean 2 purify drivers total, or per channel? If two per channel do you use them as 2.5 way or MTM?
Also what size cabinets and how do they measure?
I am using 1 per channel in sealed enclosures and really like the sound however I am using a pair of subs that I would love to delete so considering some enclosure size experiments and possibly another pair as 2.5 way.
Maybe buy a pair of the mid version and use it like a 3 way with both running with no high pass and the 'bass' pair low passed to supplement below 600 where I start too get some roll off.
These monoblocks produce 450W (and are stable into a 2 ohm load). The system sounds really good and very dynamic with the 2 Purifi drivers in a sealed enclosure.
Can you tell a bit more about your implementation? Do you mean 2 purify drivers total, or per channel? If two per channel do you use them as 2.5 way or MTM?
Also what size cabinets and how do they measure?
I am using 1 per channel in sealed enclosures and really like the sound however I am using a pair of subs that I would love to delete so considering some enclosure size experiments and possibly another pair as 2.5 way.
Maybe buy a pair of the mid version and use it like a 3 way with both running with no high pass and the 'bass' pair low passed to supplement below 600 where I start too get some roll off.
I gave the link in the post you're questioning to my build (here is the link again).
I won't re-describe the build as the description is already on that referenced post (783) on p 79. I also gave some F/U on posts 788 and 795.
In short, it uses two 8-0hm Purifi drivers in parallel per sealed cabinet.
I do not like the sound of MTM (except for desktop, computer monitors) and stopped building that style some time ago.
Since writing the description, I've added subs with active 4th LR X/Os at ~45Hz to the build. The subs have their own amps and thus work for only the bottom octave. This change noticeably cleaned up the midrange as the Purifi's are no longer trying to (inefficiently) move air in that bottom octave.
One other system change: I'm now using an icOn 4PRO passive preamp (manufacturer here, Pal the owner is very nice to deal with; one review here).
I won't re-describe the build as the description is already on that referenced post (783) on p 79. I also gave some F/U on posts 788 and 795.
In short, it uses two 8-0hm Purifi drivers in parallel per sealed cabinet.
I do not like the sound of MTM (except for desktop, computer monitors) and stopped building that style some time ago.
Since writing the description, I've added subs with active 4th LR X/Os at ~45Hz to the build. The subs have their own amps and thus work for only the bottom octave. This change noticeably cleaned up the midrange as the Purifi's are no longer trying to (inefficiently) move air in that bottom octave.
One other system change: I'm now using an icOn 4PRO passive preamp (manufacturer here, Pal the owner is very nice to deal with; one review here).
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bipole (Push push front and back Magnets supported with common brace) is an excellent approach. Iirc planet10 explained the benefits of this approach well quite awhile ago. Thank you for reminding me/ us
But one I don’t recall him mentioning no baffle step loss (BSL). I could kind of imagine it … I should revisit that. But just to confirm the bottom line - it’s actually eliminated?
I just read up a bit, it sounds great … but the LU1014 Group Buy is closed. If another one opens …
waveguide yea or nay?
Waveguide yea or nay?
I'm getting closer to doing an IRL build and started with a baffle mold that puts too much tension on the fabric (rib structure composite build). As the construction strategy is being adjusted to deal with said problem I'm seriously considering implementing a full on waveguide into the baffle. There was going to be a 9" pseudo waveguide, but I'm thinking I could crank it up to 11.
Any thoughts as to whether the Ptt6.5 in waveguide is desirable? Thoughts on the current profile?
The dimensions are 12" OD X 5.8" ID X 2.25" deep, putting the contact about mid way on the butyl surround's flat bond surface. Not worried about the connectivity particulars at the moment, just the inner profile and whether it is/is not beneficial to use a large waveguide in general.
Waveguide yea or nay?
I'm getting closer to doing an IRL build and started with a baffle mold that puts too much tension on the fabric (rib structure composite build). As the construction strategy is being adjusted to deal with said problem I'm seriously considering implementing a full on waveguide into the baffle. There was going to be a 9" pseudo waveguide, but I'm thinking I could crank it up to 11.
Any thoughts as to whether the Ptt6.5 in waveguide is desirable? Thoughts on the current profile?
The dimensions are 12" OD X 5.8" ID X 2.25" deep, putting the contact about mid way on the butyl surround's flat bond surface. Not worried about the connectivity particulars at the moment, just the inner profile and whether it is/is not beneficial to use a large waveguide in general.
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The GB is closed but I don’t think you need the GB JFETs to build (technically don’t need to be matched as each channel only uses 1). And as they are still available new old stock (LD1014D is the SMT mount which is what you really want for mounting in thermal IMS TO-247 adapter. I have some extras I could send you if you want to build the LuFo.
Waveguide on a 6.5in midwoofer is to improve efficiency or improve mid range polars? Or both? Interesting idea but the cabinet baffle is now wide. One of the attractions of Purifi was 8in woofer performance in 6.5in package. Plus, you have moved the acoustic center of the woofer even father back making time alignment with the tweeter more difficult. Putting the tweeter on waveguide to move it back helps but ideally, tweeter needs to sit behind the woofer to get time alignment.
Pushing the woofer back a little could help the tweeter, at least with conventional crossover techniques.
@X, @Allen B
Starting to think that listening preference is going to be the decisive factor-
I've heard the 'nearly perfect' sounding full range rigs that basically are amazing for acoustic guitar w/vocals. That is not what I want. I like intense 'holographic' sound that works well with industrial/electronic music. Heavy/rich/punchy, if I had to use three words about my system goal.
One strategy that (at least on paper) seems to do what I want is the omnidirectional stuff. I've never heard one so I don't know if this is actually what I want. To Allen's and X's points about alignment; it looks like the omni config. will solve this issue as an added bonus?
Judging on listening preference alone would omni be a contender or should I be in slim baffle camp, or wide curve baffle camp, and finally the big fat waveguide camp? I have four baffle (two under construction) geometries emerging each is quite different; but not sure what to mainly focus on. Also, everything recent has a coaxial tweeter, for better or for worse, so there's that.
Starting to think that listening preference is going to be the decisive factor-
I've heard the 'nearly perfect' sounding full range rigs that basically are amazing for acoustic guitar w/vocals. That is not what I want. I like intense 'holographic' sound that works well with industrial/electronic music. Heavy/rich/punchy, if I had to use three words about my system goal.
One strategy that (at least on paper) seems to do what I want is the omnidirectional stuff. I've never heard one so I don't know if this is actually what I want. To Allen's and X's points about alignment; it looks like the omni config. will solve this issue as an added bonus?
Judging on listening preference alone would omni be a contender or should I be in slim baffle camp, or wide curve baffle camp, and finally the big fat waveguide camp? I have four baffle (two under construction) geometries emerging each is quite different; but not sure what to mainly focus on. Also, everything recent has a coaxial tweeter, for better or for worse, so there's that.
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Haze Head I know my replies to your posts are a broken record with a stuck groove, what the heck let's play it again "amazing designs and renders there, CLICK amazing designs and renders there, CLICK amazing designs and renders there, CLICK amazing designs and renders there, CLICK". As to which to build because you "like intense 'holographic' sound that works well with industrial/electronic music. Heavy/rich/punchy, if I had to use three words about my system goal." I lean towards your omnidirectional concept. The caveat is what you personally mean by 'holographic'. Filling the room with the music with a softer focused imaging clues is what omnidirectional is all about. If in your concept of holographic you include very sharp edge enhanced pinpoint imaging then direct radiators are the path to take.
Jimk04 I would vote go with the X long stroke woofer, because I am addicted to Purifi bass and I like the capability to crank it loud and deep to stupid levels. And not just music. Recently we have been rewatching the HBO series Band of Brothers and before that The Tomorrow War. War and action sci-fi movies really allow the PTT6.5s to strut their stuff in bass and dynamics. On the more subtle beauty side recent highlights have been the UHQR Kind of Blue, wow just wow. Back to which woofer in theory I believe one area where the W would go in one of my designs is if the speaker were slated for use with tubes or other lower power amplification where the extra 1.6 SPL@2.83Vrms/1m may help. I am not aware of any field reports on how this works in actual practice for the newer W spec drivers.
And here are some NICE designs using PTT4.0 from Joachim Gerhard.
https://www.monoandstereo.com/2021/07/new-joachim-gerhard-collection-speakers.html#more
Jimk04 I would vote go with the X long stroke woofer, because I am addicted to Purifi bass and I like the capability to crank it loud and deep to stupid levels. And not just music. Recently we have been rewatching the HBO series Band of Brothers and before that The Tomorrow War. War and action sci-fi movies really allow the PTT6.5s to strut their stuff in bass and dynamics. On the more subtle beauty side recent highlights have been the UHQR Kind of Blue, wow just wow. Back to which woofer in theory I believe one area where the W would go in one of my designs is if the speaker were slated for use with tubes or other lower power amplification where the extra 1.6 SPL@2.83Vrms/1m may help. I am not aware of any field reports on how this works in actual practice for the newer W spec drivers.
And here are some NICE designs using PTT4.0 from Joachim Gerhard.
https://www.monoandstereo.com/2021/07/new-joachim-gerhard-collection-speakers.html#more
This, with its small woofer, strikes me as a (post-)modern incarnation of the ProAc Tablette. I bet it sounds amazing above 80 hz or so.
You have so many amazing looking designs there. Before spending a lot of filament lay down time and fortune on 3d printing, making mock ups out of foam core and listening might be worthwhile.
I don’t think you get holographic imaging with omnis. Narrow, good round overs on baffles seem to do better there. Good XO implementation is also critical.
@X
Yes, it seems I was conflating imaging with something different. Having recently stumbled on the LXminis and all the praise it got me thinking about that config. strategy. I really need to just hear the various styles for myself, and like you recommend, just try them out in lesser developed iterations. The initial thinking with the 'pseudo waveguide' and full waveguide was to minimize baffle edge diffraction, with the waveguide being the 'first edge' encounter. Thus freeing up the ability to have a more diffractively intrusive geometry after the waveguide. In other words, have a large frontal area but mitigate the usual consequence of doing so.
At any rate, I solved my construction challenge and now have a viable set of techniques to make lightweight/stiff iso-grid panels. The 12" X 18" baffle with 8.5" to 5.75" pseudo waveguide weighed in at 1 pound. So a 15L cab would probably be around 5 pounds, or as little as 2.5 if I want to get extreme with the layup. It's a huge step toward getting the PTT boxed!
Yes, it seems I was conflating imaging with something different. Having recently stumbled on the LXminis and all the praise it got me thinking about that config. strategy. I really need to just hear the various styles for myself, and like you recommend, just try them out in lesser developed iterations. The initial thinking with the 'pseudo waveguide' and full waveguide was to minimize baffle edge diffraction, with the waveguide being the 'first edge' encounter. Thus freeing up the ability to have a more diffractively intrusive geometry after the waveguide. In other words, have a large frontal area but mitigate the usual consequence of doing so.
At any rate, I solved my construction challenge and now have a viable set of techniques to make lightweight/stiff iso-grid panels. The 12" X 18" baffle with 8.5" to 5.75" pseudo waveguide weighed in at 1 pound. So a 15L cab would probably be around 5 pounds, or as little as 2.5 if I want to get extreme with the layup. It's a huge step toward getting the PTT boxed!
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