The reason is that vented or PR boxes REDUCE required excursion around the tuning frequency. This means that the driver will not work as hard and lower HD from the driver will result.
That's basic physics.
Wolf
But the sound is worse and the cabinets need to be bigger. This driver is specifically designed for this. Which is why it has a 4 layer voice coil. If you ask the Purifi team the best way to use this driver, they would tell you this as well.
From a conversation with Lars last year:
"It all depends on performance and cost objectives of course. For highest quality (but not the loudest) I would go for sealed and DSP EQ and excursion limitation. Preferably adding a third woofer e.g. on the back - could be rolled off with and LP filter at say 100Hz to serve as a sub assist. Could also do some directivity control.
A PR system has a fifth order highpass transfer function including a deep null at the PR free field resonance (17Hz for the 80g version). This null is very hard to EQ (borderline non minimum phase and the woofer and PR are completely out of phase here) so it’s difficult to get very deep bass extension. A sealed box is a simpler 2nd order high pass that can be EQed down to any frequency (with a proper excursion limited). Personally, I prefer an EQ to a 2nd order high pass at 20Hz with Q=0.5 ie critical damping aka aperiodic. The EQ filter necessary is a 2nd order shelving filter often called a Linkwitz (named after Siegfried Linkwitz co inventor of the LR crosover filters)
The advantage of a PR (or port ) is that the excursion to SPL efficiency of the woofer is increased (acts like extra cone area) but only just around the tuning frequency and below excursion explodes."
"It all depends on performance and cost objectives of course. For highest quality (but not the loudest) I would go for sealed and DSP EQ and excursion limitation. Preferably adding a third woofer e.g. on the back - could be rolled off with and LP filter at say 100Hz to serve as a sub assist. Could also do some directivity control.
A PR system has a fifth order highpass transfer function including a deep null at the PR free field resonance (17Hz for the 80g version). This null is very hard to EQ (borderline non minimum phase and the woofer and PR are completely out of phase here) so it’s difficult to get very deep bass extension. A sealed box is a simpler 2nd order high pass that can be EQed down to any frequency (with a proper excursion limited). Personally, I prefer an EQ to a 2nd order high pass at 20Hz with Q=0.5 ie critical damping aka aperiodic. The EQ filter necessary is a 2nd order shelving filter often called a Linkwitz (named after Siegfried Linkwitz co inventor of the LR crosover filters)
The advantage of a PR (or port ) is that the excursion to SPL efficiency of the woofer is increased (acts like extra cone area) but only just around the tuning frequency and below excursion explodes."
ADude,
it's trivial to shove it into the smallest box and load it with as much volts as I want, and use DSP for equalization and crossover and time alignment and using HP filters to prevent over-excursion and limiters to prevent damage.
It's harder to do an all passive design which only needs one amplifier.
Some of us are suckers for punishment- no DSP, no waveguide. Not even a custom box... just some box and tweeter I had laying around
Exploring Purifi Woofer Speaker Builds
it's trivial to shove it into the smallest box and load it with as much volts as I want, and use DSP for equalization and crossover and time alignment and using HP filters to prevent over-excursion and limiters to prevent damage.
It's harder to do an all passive design which only needs one amplifier.
Some of us are suckers for punishment- no DSP, no waveguide. Not even a custom box... just some box and tweeter I had laying around
Exploring Purifi Woofer Speaker Builds
Last edited:
Yeah been there done that, sealed with DSP and loading it with 200W was so, 2010...
Back to passive, I am...
Sure I could go active multi-amped DSP on everything, but not everyone is pop song hitmaker or studio executive who can afford a soffit 7.4.4 Atmos system in their studio... nor want cables everywhere...
I think DSP and active is good for 2 channel but costs pile up after that.
Adude, Let me know where I can find a 3-4 channel amp with DSP with IIR/FIR and BlueTooth/Airplay/WISA for around under $1000 and take me on this journey with you...
Back to passive, I am...
Sure I could go active multi-amped DSP on everything, but not everyone is pop song hitmaker or studio executive who can afford a soffit 7.4.4 Atmos system in their studio... nor want cables everywhere...
I think DSP and active is good for 2 channel but costs pile up after that.
Adude, Let me know where I can find a 3-4 channel amp with DSP with IIR/FIR and BlueTooth/Airplay/WISA for around under $1000 and take me on this journey with you...
Last edited:
He should request a sample from Oleh at Camerton. Shipping is much shorter.
I believe throwing money at things is not great engineering, but that's my view. But it certainly is going to reduce your profits.
After my experiment with the 6.5PTT with what I had laying around:
Exploring Purifi Woofer Speaker Builds
I'm having cabinets being built for a dual triple 8" Purifi 3-way, just patiently waiting for Lars' 16" ohm variant. (If they're not available, never mind I have a backup- I'm having twin 12" 3 way cabinets being built) for non-Purifi 12" woofers... I also want to flesh it out with a PTT 4"2 way in just 2.5L.
But of course it ain't done til it's done. And we all love all our babies just the same, so don't always want to show pictures to the world until we think we can take all the critique and comparison questions.
But back to your point, ADude if you haven't seen it I'm sure you're just very busy. But has been done!
Dennis Murphy and the late Rick Craig (RIP) have already done twin woofered' 2 and 3-ways with the 6.5" PTT, already ahead of the game and on the market months ago at Salk Sound and Squarespace - Website Expired (now defunct) Rick was no stranger to DSP either...
Last edited:
I’ve seen a few twin woofer speakers. But not active twin woofers in a small sealed with Linkwitz transform. My project is an in-wall, so I get a free 6dB of boost in the low end as well.
But with the upcoming 8” Purifi and Bliesma mid, I’ll be replacing the Purifi for the mid role, and dual 6.5’s will just be a system for smaller 2 channel rooms.
My flagship setup will have 4x Purifi 8’s, and probably will go with an MTM with the Bliesma 3” mids and T34 tweeter. All fully active, and sealed. Just so I’m not working the bag off the Bliesma under high SPL conditions.
But with the upcoming 8” Purifi and Bliesma mid, I’ll be replacing the Purifi for the mid role, and dual 6.5’s will just be a system for smaller 2 channel rooms.
My flagship setup will have 4x Purifi 8’s, and probably will go with an MTM with the Bliesma 3” mids and T34 tweeter. All fully active, and sealed. Just so I’m not working the bag off the Bliesma under high SPL conditions.
If you're going in-wall then you may have constraints limiting you to sealed.
But a properly designed vented box or passive radiator or tapped horn etc has some pros than a sealed box can't match. Some cons too. But it's all a balance of tradeoffs and what you're willing to take.
A BIG ported box with a low tuning frequency that behaves like a sealed until the very lowest frequencies, +/- excursion control, whether that be with careful analogue design or easy DSP filtering, is something to behold...
But a properly designed vented box or passive radiator or tapped horn etc has some pros than a sealed box can't match. Some cons too. But it's all a balance of tradeoffs and what you're willing to take.
A BIG ported box with a low tuning frequency that behaves like a sealed until the very lowest frequencies, +/- excursion control, whether that be with careful analogue design or easy DSP filtering, is something to behold...
I go with sealed regardless of in wall or not. The only drawback with an active sealed is you don’t get the free non-linear boost at the port or PR tuning frequency. But if you can’t get the SPL’s you’re looking for, just add more woofers and more power. Nothing sounds better than a sealed cabinet. More room friendly as well.
Actually I’m helping a friend tune up a 4x 6.5” Purifi woofer sealed, active speaker next week. Using my amps to drive them.
Actually I’m helping a friend tune up a 4x 6.5” Purifi woofer sealed, active speaker next week. Using my amps to drive them.
And I’m familiar with big ported woofers. I have some massive 200l cabinets with these woofers in them sitting in my storage.
http://nedlab.com/wp/wp-content/uploads/2014/06/Focal-AUDIOM-15KX.pdf
Nobody will buy them because they’re too big.
http://nedlab.com/wp/wp-content/uploads/2014/06/Focal-AUDIOM-15KX.pdf
Nobody will buy them because they’re too big.
Last edited:
They've done that ever since they took over DST and drivers don't stay around for long.
Audiom- oh that thing is ancient, but still a good woofer. 15” high sensitivity woofer with 6mm x-max.
Charlie Laub was looking for something like that.
But I agree to disagree that sealed is the only solution. It’s inefficient and so it you don’t care about SPL then fine. But for stage or large touring or large venues (cinemas, supersize nightclubs) efficiency and low distortion and SPL at sub-bass <50Hz is vital. Throwing more drivers and amps at it won’t help.
You need an acoustic solution- that’s not knife, this is a a knife- a modern large AND long throw subwoofer in large cabinet. Only 1000L here:
Data-Bass: Subwoofer Measurements
Look what the Kii Three can do with 4 woofers under 200hz in a tiny box and 4 200W nCore amps vs. 1 ported Purifi?
Kii Audio THREE Review
Selah Audio Purezza Bookshelf Speaker Review
Advantage is a smaller box (and mid-bass steering) not the low frequency extension, SPL or distortion
Charlie Laub was looking for something like that.
But I agree to disagree that sealed is the only solution. It’s inefficient and so it you don’t care about SPL then fine. But for stage or large touring or large venues (cinemas, supersize nightclubs) efficiency and low distortion and SPL at sub-bass <50Hz is vital. Throwing more drivers and amps at it won’t help.
You need an acoustic solution- that’s not knife, this is a a knife- a modern large AND long throw subwoofer in large cabinet. Only 1000L here:
Data-Bass: Subwoofer Measurements
Look what the Kii Three can do with 4 woofers under 200hz in a tiny box and 4 200W nCore amps vs. 1 ported Purifi?
Kii Audio THREE Review
Selah Audio Purezza Bookshelf Speaker Review
Advantage is a smaller box (and mid-bass steering) not the low frequency extension, SPL or distortion
Last edited:
Rabbitz,
You’re right. Since Ken Kantor spearheaded the takeover, it was the beginning of the end.
What’s unclear is what drivers will remain? Even the new models are not readily available eg. SDF
It looks like they may all go. I can’t get a clear answer from WES, but o won’t blame them because maybe they don’t know either…
You’re right. Since Ken Kantor spearheaded the takeover, it was the beginning of the end.
What’s unclear is what drivers will remain? Even the new models are not readily available eg. SDF
It looks like they may all go. I can’t get a clear answer from WES, but o won’t blame them because maybe they don’t know either…
If you want to go big no point messing around. Yevgeniy needs some of these in for testing.
Ascendo’s Seismic Subwoofer Is a Modern Marvel | Sound & Vision
Ascendo’s Seismic Subwoofer Is a Modern Marvel | Sound & Vision
According to my modelling, in that cabinet he will be able to reach 12mm excursion @ 107db with an F3 of 30hz. Or 112dB with an F3 of 40hz. And a nice flat smooth roll off as well. Tight clean bass. No port noise, and no passive radiator noise. For him in his small room it’s enough.
The Selah speaker with passive radiator has an F3 of 65hz.
The Selah speaker with passive radiator has an F3 of 65hz.
Last edited: