105db peak spl at listening position would give good headroom for classical music with high dynamic range and plenty loud for others styles that used compression
I agree. The primary advantage that the PTT series drivers have is extreme excursion capability with very low distortion in the deep bass, AND linear low distortion response in the midrange, at the same time. A PTT10 can match the performance of many 15" woofers in the deep bass, from the standpoint of SPL and distortion, and it can also play clean and flat well above 1k, and it can do it in a much smaller cabinet.
If there is room for a 15" driver, and we only need it to play up to 200 Hz, then a PTT10 would have a lot of unused capability.... like using a Bliesma T34B as a super tweeter crossed at 8k...
To add an answer to my own question, I found this excellent review which contains a small anecdote of the differences between the 6.5M and X.
From https://hificompass.com/en/reviews/purifi-ptt65m08-nfa-01a-65-true-midrange
Regarding the low end, if crossover can be >150hz, the M is a better option I think.
Also, I’m guessing some notch filters are required between 3-8k if using a shallow slope? Not really relevant for me, with LR4 (and probably MTM), but nonetheless interesting.
From https://hificompass.com/en/reviews/purifi-ptt65m08-nfa-01a-65-true-midrange
So I wonder if that ~2ms difference between them in the transient response from peak to return is an advantage? Or is “open and easy” purely a result of a shallow slope?
Regarding the low end, if crossover can be >150hz, the M is a better option I think.
Also, I’m guessing some notch filters are required between 3-8k if using a shallow slope? Not really relevant for me, with LR4 (and probably MTM), but nonetheless interesting.
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Are we also considering baffle step correction? With typical baffle widths somewhere around 200 Hz is where one needs to increase bass output to balance forward radiating upper frequencies with omni directional bass. My opinion is a big advantage ot 3 way and 2 1/2 way designs is the control one gets for BSC without need to chop off mids and highs using crossover filters as required in 2 way designs.
Therefore IMHO use the M driver for mids and a PTT8 or 10 for bass. That will be very fine indeed.
I have been using the Purify 6.5" long throw since it first came out in a hi-end 16Kw PA rig in my studio.
I also use Alcons ribbons and the 6.5" crosses those beautifully at 1100Hz and then run down till 450Hz, when a 18sound 12NTLW3500 starts and runs to 80Hz, then an Eminence-nsw6021 sub takes over.
There is definitely a loss of detail but increase in punch below the 450Hz cross point with the 18sound.
My question is would it be an idea to go 5-ways and fit a 10" Purify at say (~250/300Hz - 700/800Hz).
Or will it be a lot of expense for little additional benefit - and end up with the same i.e. more detail but a loss of kick ?
PA speakers + amps + custom crossovers etc.. can be seen working in the background here:
I also use Alcons ribbons and the 6.5" crosses those beautifully at 1100Hz and then run down till 450Hz, when a 18sound 12NTLW3500 starts and runs to 80Hz, then an Eminence-nsw6021 sub takes over.
There is definitely a loss of detail but increase in punch below the 450Hz cross point with the 18sound.
My question is would it be an idea to go 5-ways and fit a 10" Purify at say (~250/300Hz - 700/800Hz).
Or will it be a lot of expense for little additional benefit - and end up with the same i.e. more detail but a loss of kick ?
PA speakers + amps + custom crossovers etc.. can be seen working in the background here:
Attachments
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A couple of links I have been intending to share here may help with ZestClub’s consideration of adding PTT10s to his high-powered quad amped club system. The 1799 & 2800 designs by Joseph Crowe use Purifi woofers in hybrid Altec A7 configuration of front horn loading with rear reflex/PR loading. My guess is the front horns will help with ‘punch’ and ‘kick’ ZestClub is looking for. Beyond ZestClub’s application for the currently 135 pages of this thread a discussion point raised time and again is if one’s application allows the BIG boxes 12-15-18-21 inch drivers require that such jumbo drivers edge out Purifi’s. In his careful testing Joseph shows pairs of PTT8s or PTT10s have 5 to 12 dB lower distortion vs best 15” woofers tested.
![room_3_480x480[1].jpg](https://www.diyaudio.com/community/attachments/room_3_480x480-1-jpg.1397393/ "room_3_480x480[1].jpg")
He goes on to report in his 1799 design:
“Max Output (bandwidth limited to 45Hz)
Dual 10" Purifi: 118dB SPL 1m
Single 15" Beyma: 122dB SPL 1m
Max Output (bandwidth limited to 24Hz)
Dual 10" Purifi: 116dB
Single 15" Beyma: 115dB SPL 1m
So we can see that the dual 10" Purifi offers similar maximum output capability but with the added benefit of deeper bass extension.”
https://josephcrowe.com/blogs/news/...-cabinet-no-1799-using-dual-10-purifi-woofers
Other Purifi related links in Joseph Crowe’s blog posts:
https://josephcrowe.com/blogs/news/speaker-system-no-2800
https://josephcrowe.com/blogs/news/purifi-ptt8-0x04-nab-02-8-aluminum-cone-woofer
https://josephcrowe.com/blogs/news/speaker-design-study-using-new-purifi-8-woofer
He goes on to report in his 1799 design:
“Max Output (bandwidth limited to 45Hz)
Dual 10" Purifi: 118dB SPL 1m
Single 15" Beyma: 122dB SPL 1m
Max Output (bandwidth limited to 24Hz)
Dual 10" Purifi: 116dB
Single 15" Beyma: 115dB SPL 1m
So we can see that the dual 10" Purifi offers similar maximum output capability but with the added benefit of deeper bass extension.”
https://josephcrowe.com/blogs/news/...-cabinet-no-1799-using-dual-10-purifi-woofers
Other Purifi related links in Joseph Crowe’s blog posts:
https://josephcrowe.com/blogs/news/speaker-system-no-2800
https://josephcrowe.com/blogs/news/purifi-ptt8-0x04-nab-02-8-aluminum-cone-woofer
https://josephcrowe.com/blogs/news/speaker-design-study-using-new-purifi-8-woofer
Interesting that Joseph Crowe’s Dual 10" Purifi: can reach 118dB SPL 1m, that's definitely in PA territory.
I hadn't thought of using 2 together in this configuration.
Its almost felt since the first long throw Purifi 6.5" came out that they had potential to be used where higher volumes were required.
From memory I think back in the day Lars Risbo mentioned that the Purifi line up would eventually go to 12" - one or two of those in this kind of configuration with ultra low distortion would be a jaw dropper, although an expensive one!
The custom re-built 4-way analog crossovers (shown in the above studio photo) are here if anyone is interested: https://www.diyaudio.com/community/threads/dbx-234xl-opamp-crossover-upgrade.416571/
I hadn't thought of using 2 together in this configuration.
Its almost felt since the first long throw Purifi 6.5" came out that they had potential to be used where higher volumes were required.
From memory I think back in the day Lars Risbo mentioned that the Purifi line up would eventually go to 12" - one or two of those in this kind of configuration with ultra low distortion would be a jaw dropper, although an expensive one!
The custom re-built 4-way analog crossovers (shown in the above studio photo) are here if anyone is interested: https://www.diyaudio.com/community/threads/dbx-234xl-opamp-crossover-upgrade.416571/
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I'm curious, and have not done much DIY with speakers for some years.
But what is possible with a 10" 8ohm Purify bass driver within a sealed enclosure? Or would two 8" Purify be a better option?
Two things I would like to have in a speaker system bass performance, low frequency extension, and what I would guess is decribed as slam, attack, percussive quality. A sealed box would be preferable simply from a build perspective.
The reality is I can't say I have heard many hifi speakers do that percussive slam. At a recent hifi show with my son, we enjoyed a lot of high resolution speakers, but the difference in presentation, stage width and imaging was evident, the real issue was just bass performance, percussion, speed, slam or whatever you want to call it. Sure many went low, but often with a tubby sub quality.
The slam and pecussion my lad was asking about is like what you get from a 15" pro driver in some systems. I also remember it from 18" bass drivers by Celestion when I was 16, and it was present with the PMC BB5/XBD, and even in some unspectacular PA speakers from the likes of JBL and Cerwin Vega.
But what is possible with a 10" 8ohm Purify bass driver within a sealed enclosure? Or would two 8" Purify be a better option?
Two things I would like to have in a speaker system bass performance, low frequency extension, and what I would guess is decribed as slam, attack, percussive quality. A sealed box would be preferable simply from a build perspective.
The reality is I can't say I have heard many hifi speakers do that percussive slam. At a recent hifi show with my son, we enjoyed a lot of high resolution speakers, but the difference in presentation, stage width and imaging was evident, the real issue was just bass performance, percussion, speed, slam or whatever you want to call it. Sure many went low, but often with a tubby sub quality.
The slam and pecussion my lad was asking about is like what you get from a 15" pro driver in some systems. I also remember it from 18" bass drivers by Celestion when I was 16, and it was present with the PMC BB5/XBD, and even in some unspectacular PA speakers from the likes of JBL and Cerwin Vega.
The 18Sound 15" and 12" 12NTLW3500 can really slam, and having modern tetracoil motors have good clarity for PA speakers.
They are certainly in a different league from the brands you mentioned. Never the less, they lack the clarity of a hi-end driver for sure, and that's the holy grail - having both.
They are certainly in a different league from the brands you mentioned. Never the less, they lack the clarity of a hi-end driver for sure, and that's the holy grail - having both.
The holidays finally brought my new Purifi build home. I must confess, I contracted the professional expertise of MG from Rose-Handwerk. I could not have built such solid boxes. So this is custom build and not really DIY.
The upper boxes with 6.5-inch aluminium 4-ohm mids and Viawave GRT-145-8 tweeters are very pure (as measured and experienced). The 10-inch sub boxes have no lining or stuffing at present. So would appreciate any feedback folks might have from the charts below.
The sub drivers are PTT10.0X04-NAB-01 with PTT10.0PR-NA2-01 passives carrying 200g each side. The sub boxes are 40x40x60cm. Though take off 28mm for the MDF.
Here are REW SPL measurements for the sub and mids from three inches away. I am not too fussed about the absolute dB levels. The REW SPL meter hit 75dB with periodic pink noise running before I ran the measuremenrts. Here is left:
And right:
Here is what SoundID Sonarworks saw for ATMOS purposes with the same LFE signal going through both sides at the same time. Got the same dipping of the subs around 50Hz.
I am running an active crossover (fourth order at 200Hz and at 3000Hz) and crosstalk cancellation (XTC) and room correction (ORC) from Theoretica BACCH4Mac. The XTC figures over 10 are considered quite good.
Here is before ORC room correction in bold vs. after in shadow:
Here is after ORC room correction in bold vs. “optimal” in shadow:
And here is the REW RTA view after BACCH XTC and ORC using pink noise (again not too fussed about absolute dB level indicated... it was loud enough in the room!)
Still wondering if I should stuff any materials or linings in the subs, e.g., blackhole for the back wall. They are pretty bare inside:
The upper boxes with 6.5-inch aluminium 4-ohm mids and Viawave GRT-145-8 tweeters are very pure (as measured and experienced). The 10-inch sub boxes have no lining or stuffing at present. So would appreciate any feedback folks might have from the charts below.
The sub drivers are PTT10.0X04-NAB-01 with PTT10.0PR-NA2-01 passives carrying 200g each side. The sub boxes are 40x40x60cm. Though take off 28mm for the MDF.
Here are REW SPL measurements for the sub and mids from three inches away. I am not too fussed about the absolute dB levels. The REW SPL meter hit 75dB with periodic pink noise running before I ran the measuremenrts. Here is left:
And right:
Here is what SoundID Sonarworks saw for ATMOS purposes with the same LFE signal going through both sides at the same time. Got the same dipping of the subs around 50Hz.
I am running an active crossover (fourth order at 200Hz and at 3000Hz) and crosstalk cancellation (XTC) and room correction (ORC) from Theoretica BACCH4Mac. The XTC figures over 10 are considered quite good.
Here is before ORC room correction in bold vs. after in shadow:
Here is after ORC room correction in bold vs. “optimal” in shadow:
And here is the REW RTA view after BACCH XTC and ORC using pink noise (again not too fussed about absolute dB level indicated... it was loud enough in the room!)
Still wondering if I should stuff any materials or linings in the subs, e.g., blackhole for the back wall. They are pretty bare inside:
Throw some acoustic felt/foam in there.
The peaks in the measured FR >= 300Hz are probably enclosure resonances. 340m/s / ~310Hz / 2 = 55cm --> this is the inner height of the woofer enclosure, or? Some damping will eliminate that...
The peaks in the measured FR >= 300Hz are probably enclosure resonances. 340m/s / ~310Hz / 2 = 55cm --> this is the inner height of the woofer enclosure, or? Some damping will eliminate that...
Can you link it? I don't see it say that anywhere. I only see where he makes an unverified claim that the dual 10's could play with lower distortion than a single 15". Theres no data.
Thanks, will do! The results above were the encouragement I needed to learn the CAD tools a bit better. By playing with the Qa fill / lining factor in VituixCAD (from 120 = no fill up to 5 = heavy fill) I can see the projected improvement around 50Hz. Latest when I disassemble the speakers in Spring to take them outside for final coat painting, if not sooner, I will rectify this.
Very nice...🙂
If they are not finished, add also some bracing inside....big box with heavy cone drivers needs that desparately...
You could/should couple passive cones with MDF bars for forces cancelling and add bracing to the biggest surfaces to break them in smaller ones. It will vibrate significantly less and you will hear that. Drivers of that level deserve dead box....
If they are not finished, add also some bracing inside....big box with heavy cone drivers needs that desparately...
You could/should couple passive cones with MDF bars for forces cancelling and add bracing to the biggest surfaces to break them in smaller ones. It will vibrate significantly less and you will hear that. Drivers of that level deserve dead box....
Has anyone compared between PTT8 and PTT10? I currently run a pair of PTT8 and is wondering if going to 10 would make a difference.
I have compared PTT10 to the Peerless XXLS 12” and for sure the PTT10.0 beats the XXLS 12” (as well as a pair of PTT8.0)
Percussion lives between 50Hz and 10KHz, which is why I believe maximum SPL in those frequencies is what makes a speaker sound dynamic, as opposed to subwoofers ie. frequencies 16-40HZ.
As you may recall Hoffman’s iron law- which can be summarised as-
out of
1. deeper bass extension,
2. SPL/watt
3. smaller box size,
You can have 2 out of 3, but not all 3.
BB5/X5B have a pair of 15" woofers which maximises their headroom/dynamic range SPL thermally limited region of the mid bass ~60-400Hz.
It would need to take some serious benchmarking, someone like @HiFiCompass would able to do conduct to see if a single PTT10.0X which would play cleaner at a life-like SPL Eg. percussive transients in excess of 115dB/1m than a 15” woofer, with a larger 3” voice coil, more than twice the Sd (760cm^2) and 10dB sensitivity advantage (94dB/W),
So the Volt woofer have only x-max of 7.5mm, but remember that large excursion helps the most the lower you go on frequency
It may well take a future PTT12.0X to beat others manufacturers 15” woofers form 1KHz down all the way to 20Hz…
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The Percussion range is very wide as you point out, with even lower frequency instruments having some high frequency components as well.
In my case the Alcons pro ribbons provide the above 1100Hz range with up to 130db range delivering sound dynamics in spades. The issue is the lower frequencies 80-800Hz especially male vocals in that range.
Helpful chart - though female vocalists can go higher than shown for example: G6 1568 Hz, C7, D7, and even higher ranges, which would be well over 2000Hz and sometimes closer to 3000Hz. Mariah Carey can frequently reach notes above C7 (around 2093 Hz), sometimes even going into the E7 (around 2637 Hz) and F7 range.
In my case the Alcons pro ribbons provide the above 1100Hz range with up to 130db range delivering sound dynamics in spades. The issue is the lower frequencies 80-800Hz especially male vocals in that range.
Helpful chart - though female vocalists can go higher than shown for example: G6 1568 Hz, C7, D7, and even higher ranges, which would be well over 2000Hz and sometimes closer to 3000Hz. Mariah Carey can frequently reach notes above C7 (around 2093 Hz), sometimes even going into the E7 (around 2637 Hz) and F7 range.
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