@Norman Tracy
I merely touched on the subject, cause I miss good midrange drivers that fit the possibilities of moderne active systems. And I wondered why not use the space under the speaker - instead of having a stand for a two-way. So if purifi made an awesome midrange with all it's low distortion and other features, that I hope also has a real benifit in sound quality - not just on paper. Then why not a 5" midrange with good sensitivity - able to cross between 400-500hz to 2Khz - where any little waveguided tweeter could easily take over. We could easily add a great woofer and still get open clear midrange - that should not pump deep bass and still blend beautifuly with the tweeter - to create that smooth clean polar repsonse. I mean.... we're talking about exellence in drivers.... and it should be placed free from walls, open and well in front of an exlusive listening position... out there on the floor.... why not use the space under it? Behind it?`Why is 20 liters a limit -when we talk about top of the line?
I just mentioned Kii3 - cause I bought the tweeter - the DXT(70 Euro)... and is so happy with it. I us it with a 5" alu midrange, that has it's first breakup at around 10Khz - I cross at 2Khz - cause - dispersion.
@Billshurv
Sorry.... it might be the wrong place and time. But having listened to so many different speakers... a dedicated midrange and dedicated bass - really bring something special to the sound IMO
I merely touched on the subject, cause I miss good midrange drivers that fit the possibilities of moderne active systems. And I wondered why not use the space under the speaker - instead of having a stand for a two-way. So if purifi made an awesome midrange with all it's low distortion and other features, that I hope also has a real benifit in sound quality - not just on paper. Then why not a 5" midrange with good sensitivity - able to cross between 400-500hz to 2Khz - where any little waveguided tweeter could easily take over. We could easily add a great woofer and still get open clear midrange - that should not pump deep bass and still blend beautifuly with the tweeter - to create that smooth clean polar repsonse. I mean.... we're talking about exellence in drivers.... and it should be placed free from walls, open and well in front of an exlusive listening position... out there on the floor.... why not use the space under it? Behind it?`Why is 20 liters a limit -when we talk about top of the line?
I just mentioned Kii3 - cause I bought the tweeter - the DXT(70 Euro)... and is so happy with it. I us it with a 5" alu midrange, that has it's first breakup at around 10Khz - I cross at 2Khz - cause - dispersion.
@Billshurv
Sorry.... it might be the wrong place and time. But having listened to so many different speakers... a dedicated midrange and dedicated bass - really bring something special to the sound IMO
Personally I've never had a tower system to compare, but I do know SWMBO does regret moving out the teeny infinity minimonitors to the kitchen so my apogee hybrids could fit in. We are very space limited in a multi-function room and they are quite wide BUT I only have 20 litres of box to play with. I could dipole all the way but I remain unconvinced bass dipoles and a tiny room is a good plan.
So for me I am down to a couple of options
1. Put in the best 6.5" I can
2. Put in a less good 6.5" and roll off a bit early and hope the sub picks up the strain ok
3. Go 3 way (hard to implement although ripoles might fit.
This is all due to my being irrationally attached to the 26" ribbons in the apogee as I like what they do even.
But I accept in their footprint I could put a 2.5, 3 or 3.5 way tower together with much cheaper drivers for a similar end goal. That is why speakers are so interesting. There are almost infinite combinations, each with their own compromises. You could go mad building different options (no names ).
@Studley: Sorry I'm just behind on projects at the moment.
So for me I am down to a couple of options
1. Put in the best 6.5" I can
2. Put in a less good 6.5" and roll off a bit early and hope the sub picks up the strain ok
3. Go 3 way (hard to implement although ripoles might fit.
This is all due to my being irrationally attached to the 26" ribbons in the apogee as I like what they do even.
But I accept in their footprint I could put a 2.5, 3 or 3.5 way tower together with much cheaper drivers for a similar end goal. That is why speakers are so interesting. There are almost infinite combinations, each with their own compromises. You could go mad building different options (no names
).@Studley: Sorry I'm just behind on projects at the moment.
Where are the builds?
Hi all.. I have been reading lots of threads on the 'new' (year old) Purifi woofers and midrange.. I found lots of chatter and discussion, but not so many 'finalised' projects and suggestions. A few companies have designed a kit..
Just wondering - Has anyone seen some good reviews and build 'using' this driver vs debating whether to use this driver?
From what I have read, the low sensitivity and high excursion make ported designs more complex, and hence the focus on passive radiators and a couple on transmission line..
Thanks!
Hi all.. I have been reading lots of threads on the 'new' (year old) Purifi woofers and midrange.. I found lots of chatter and discussion, but not so many 'finalised' projects and suggestions. A few companies have designed a kit..
Just wondering - Has anyone seen some good reviews and build 'using' this driver vs debating whether to use this driver?
From what I have read, the low sensitivity and high excursion make ported designs more complex, and hence the focus on passive radiators and a couple on transmission line..
Thanks!
Personally I've never had a tower system to compare, but I do know SWMBO does regret moving out the teeny infinity minimonitors to the kitchen so my apogee hybrids could fit in. We are very space limited in a multi-function room and they are quite wide BUT I only have 20 litres of box to play with. I could dipole all the way but I remain unconvinced bass dipoles and a tiny room is a good plan.
So for me I am down to a couple of options
1. Put in the best 6.5" I can
2. Put in a less good 6.5" and roll off a bit early and hope the sub picks up the strain ok
3. Go 3 way (hard to implement although ripoles might fit.
This is all due to my being irrationally attached to the 26" ribbons in the apogee as I like what they do even.
But I accept in their footprint I could put a 2.5, 3 or 3.5 way tower together with much cheaper drivers for a similar end goal. That is why speakers are so interesting. There are almost infinite combinations, each with their own compromises. You could go mad building different options (no names
@Studley: Sorry I'm just behind on projects at the moment.
Controlled directivity could be the answer, something like the KII 3 with 5" drivers.
Last edited:
Is it just me.... or does this little 4" driver possess a 10dB breakup around 5Khz??
PTT4.0X04-NFC-01 (PTT4.0W04-01) - PURIFI
That's about the same as my 20 year old Accuton.
PTT4.0X04-NFC-01 (PTT4.0W04-01) - PURIFI
That's about the same as my 20 year old Accuton.
There are some real in use builds on this thread as well as XRK971s transmission line solution which is on this forum.
Thank you. I’ll have to re-read. I’m interested to build a passive stand mount to supersede my LS50s that I find just a little too forensic.
Hi celef,
Expand the visualizations you reference when writing “will not the air spring within the box then work against it and act like a brake” to consider the entire amplifier + enclosure + driver system. With the convention in HiFi that amplifier is from Brand X and speaker is a Brand Y it is necessity for the amp to have a flat frequency response. Beyond that we ask it have a low output impedance (a.k.a. high damping factor) to help damp the woofers tracking of the signal by readily accepting the current kicked out of the woofer due to its back EMF (electro motive force). Classic design of a woofer + enclosure system assumes amp flat response. That is baked into the calculations, but like a multiplier that calculated to equal ‘1’ we tend to ignore the amp system. When we add non-flat response via DSP or servo circuits into the mix regardless of enclosure type the amp effects no longer being constant and linear must be considered. What was linear and constant now varies with frequency and amplitude. As you alluded to this is simpler to calculate with closed box systems because they have fewer non-linear reactive elements the ports or passive radiators introduce but the added reactive elements ports or PRs bring can be accounted for. We basically need an engineer who aced their vector calculus courses and has used that math and circuit theory in the real world to write the simulations, or software us generalists can employ.
Sure, it's there, but it seems quite easy to deal with (single peak, fairly smooth both before and after) and reflected only in the H2.
Hi billshurv,
Ah …yes…Apogiees…I still get the warm fuzzies recalling Apogee. I consider a set of Scintillas or better yet Mini-Grands top of my ones-that-got-away list.
From this admitted Purifi fan boy you only get one recommendation, your option “1. Put in the best 6.5" I can” which is one of the PTT6.5 variants. One of the things I love about my PTT6.5 + ribbon (Exploring Purifi Woofer Speaker Builds) is the mix of distortion reduction Purifi brings to the party perfectly matches the speed and delicate highs a true ribbon offers. Your other options (IMHO) are needlessly complex, a complexity that is reduces the chance of success.
I sure hope they do so! Personally, I'd prefer one that can easily go to 3Khz so the waveguide isn't needed. It would be great if the sensitivity allowed it to keep up with the PTT6.5. There currently isn't anything on the market that meets those criteria and has comparable (or better) distortion in this range. Nothing at any price; not that I've found anyway.
I would tend to disagree ported designs with PTT6.5 or PTT4.0 are more complex, Purifi's own SPK5 is ported. My theory is the cost of the drivers selects builders who are more aware of the effects of port tube tradeoffs and likely to therefore explore other technologies like TL & PR. The HiFiCompass PuriBliss-BeWg project linked below gets really deep into the topic of port addressing tube effects vs. PRs.
Here are the builds I know of in this thread and elsewhere.
Scattered among the 60+ pages of this diyAudio thread
My Fi16v1 project
https://www.diyaudio.com/forums/mul...ifi-woofer-speaker-builds-10.html#post6196918
Exploring Purifi Woofer Speaker Builds
Second listening comments Fi16v1:
Exploring Purifi Woofer Speaker Builds
Finding the limits of Fi16v1:
Exploring Purifi Woofer Speaker Builds
PTT6.5W04 and the evil twins PTT6.5PR want to explode your speaker box
https://www.diyaudio.com/forums/mul...ifi-woofer-speaker-builds-48.html#post6383932
XRK Audio designs
Simple Passive Harsch XO Using PTT6.5 and RS28F in a Waveguide
Exploring Purifi Woofer Speaker Builds
Exploring Purifi Woofer Speaker Builds
Exploring Purifi Woofer Speaker Builds
Exploring Purifi Woofer Speaker Builds
mainframe99 design & listening report:
Exploring Purifi Woofer Speaker Builds
Purifi Audio’s SPK5 application note design
https://purifi-audio.com/tech/
Articles and reviews of the SPK5
SoundStage!Hi-Fi
https://www.soundstagehifi.com/index.php/opinion/1420-purifi-audios-pint-sized-powerhouses
https://www.soundstagehifi.com/inde...-measured-performance-of-the-spk5-loudspeaker
And last a couple of pièces de résistance efforts
HiFiCompass PuriBliss-BeWg project
https://hificompass.com/ru/projects/2-way-systems/puri-bliss-bewg
https://hificompass.com/en/projects/2-way-systems/puri-bliss-be
Joseph Crowe Purifi + Satori Be kit Model 1198
https://youtu.be/iHp1rKVLOII
And his web site where the kit is offered.
https://josephcrowe.com/collections...ding-transmission-line?variant=32667137966164
Regarding the PTT4.0W04-01A's peak the review on HiFiCompass tends to agree with Paul E's comment "it seems quite easy to deal with (single peak, fairly smooth both before and after) and reflected only in the H2."
Purifi Audio PTT4.0W04-01A midwoofer | HiFiCompass
Quoting the review.
"The frequency response is very flat in the range up to 700 Hz, after which it begins to gradually decrease, falling at a frequency of 1.6 kHz by as much as 4 dB. After that, a smooth rise begins, ending with a resonant peak of the membrane at the frequency of 5 kHz. This peak is single, low Q, and smooth on both sides, so correcting it in a crossover won't cause any problems. It is quite noticeable by ear, so you will definitely have to fight with it."
"Thanks to the additional annular stiffener on the back of the membrane the typical problem of membrane edge/suspension resonance in the 2 kHz region is completely solved, as well as there are no signs of serious breakups."
"To say that the results of measuring harmonic distortion surprised me is an understatement. The new record is set, this is the lowest distortion for a 4 "midwoofer that I have encountered so far. The sound pressure level of 99 dB for such a baby is not a joke at all, and even at this pressure the average distortion level does not exceed 0.3% (-50 dB)!!!
I think that this speaker is more likely to burn out or burst into pieces before it can significantly distort the sound. Bravo!"
The waterfall plot PTT4.0
Comment on waterfall by author: "The waterfall shows the same effects as a step response, in addition exposing hidden resonances that are difficult to see in other types of measurements. In this case, no side resonances, except for the main one at 5 kHz, are observed. As I already mentioned, the Q-factor of the resonance is not very high, so the ridge on the waterfall is not very long and after a time interval of 2.5 ms decreases to the threshold of its hearness."
Author's conclusion "The measured characteristics let to classify the PTT4.0W04-01A as a 4" midwoofer of the highest class. In fact, today it is the world's best midwoofer in its class. If the concept of "Big sound out a small box" is close for you, then there is simply no better option to find. Bravo, PURIFI! "
Purifi Audio PTT4.0W04-01A midwoofer | HiFiCompass
Quoting the review.
"The frequency response is very flat in the range up to 700 Hz, after which it begins to gradually decrease, falling at a frequency of 1.6 kHz by as much as 4 dB. After that, a smooth rise begins, ending with a resonant peak of the membrane at the frequency of 5 kHz. This peak is single, low Q, and smooth on both sides, so correcting it in a crossover won't cause any problems. It is quite noticeable by ear, so you will definitely have to fight with it."
"Thanks to the additional annular stiffener on the back of the membrane the typical problem of membrane edge/suspension resonance in the 2 kHz region is completely solved, as well as there are no signs of serious breakups."
"To say that the results of measuring harmonic distortion surprised me is an understatement. The new record is set, this is the lowest distortion for a 4 "midwoofer that I have encountered so far. The sound pressure level of 99 dB for such a baby is not a joke at all, and even at this pressure the average distortion level does not exceed 0.3% (-50 dB)!!!
I think that this speaker is more likely to burn out or burst into pieces before it can significantly distort the sound. Bravo!"
The waterfall plot PTT4.0
Comment on waterfall by author: "The waterfall shows the same effects as a step response, in addition exposing hidden resonances that are difficult to see in other types of measurements. In this case, no side resonances, except for the main one at 5 kHz, are observed. As I already mentioned, the Q-factor of the resonance is not very high, so the ridge on the waterfall is not very long and after a time interval of 2.5 ms decreases to the threshold of its hearness."
Author's conclusion "The measured characteristics let to classify the PTT4.0W04-01A as a 4" midwoofer of the highest class. In fact, today it is the world's best midwoofer in its class. If the concept of "Big sound out a small box" is close for you, then there is simply no better option to find. Bravo, PURIFI! "
Yes, but this is DIY where needless complex dreams are born and dashed on a daily basis
Eventually I will see sense and do the right thing!
Interesting on the 4". I have days where I feel I actually might be able to make a cabinet for those. It passes though...
FWIW, I had Lars Risbo of PURIFI on my channel yesterday and he gave some really great "exclusive" information about their drivers, down to a demo using the hard and soft parts. Very interesting stuff that I think you guys would be interested in. I have a thread going about it here:
Interview with Lars Risbo of PURIFI Audio
Interview with Lars Risbo of PURIFI Audio
Seems like the real goal, was to make a driver that could deliver deeper bass in smaller cabinets without compromising midrange performance.
If you want a pure midrange driver.... then pro drivers could be an interesting choise.
Troels Gravesen tried a few:
high-efficiency_midrange-drivers
If you want a pure midrange driver.... then pro drivers could be an interesting choise.
Troels Gravesen tried a few:
high-efficiency_midrange-drivers