The way I see it is - what can you do with a driver with record breaking non-linear distortion?
Yes the Purifi's minimal Sd(x) variation is like having a dedicated midrange that had hardly any Sd(x) variation.
But now it has with a usable excursion, more than 1-2 mm x-max like the B&W FST, so that expands it's uses cases.
One could argue that the reason for the traditional 3 (or 4 way) speaker is to limit the bandwidth by which each transducer plays, effectively reducing Sd(x) variation. Now that Sd(x) variation is minimized, there can be different uses for the driver.
Yes the Purifi's minimal Sd(x) variation is like having a dedicated midrange that had hardly any Sd(x) variation.
But now it has with a usable excursion, more than 1-2 mm x-max like the B&W FST, so that expands it's uses cases.
- As a midwoofer in the smallest box possible. If using a traditional tweeter it may be advantageous to pay attention to cabinet diffraction and carefully chosen crossover points to allow smooth off-axis responses.
- As a woofer for a 2 way for with a tweeter in a waveguide of similar size (eg. 8" midwoofer matched to 8" waveguide)
- As a mid-woofers at the bottom of a (Jean-Michel Le Cléac'h) horn
- As mid-woofers for a (Danley-type) multiple entrance horn.
One could argue that the reason for the traditional 3 (or 4 way) speaker is to limit the bandwidth by which each transducer plays, effectively reducing Sd(x) variation. Now that Sd(x) variation is minimized, there can be different uses for the driver.
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Purifi mid seems a bit less than fully optimized for the role. You can see that in the surround. Short on driver efficiency compared to most PA mids. The extra LF response cuts dedicated midrange application a bit.
A higher efficiency transducer could better take advantage of that improved linearity, not that I know of many competitors to the Purifi there.
There's an estimation of the frame size included that throws off the result when computing directly from driver Sd. Note the .83 being squared to find the area of a circle.
You can calculate it yourself or have VituixCAD and such do it for you. The radiation from a circular baffled piston is a standard textbook result that can be found in many places.
Having looked into it a bit more, looks like 1/4 wavelength spacing is JUST achievable if you cross around 1375hz and use 2 of the 4" drivers in parallel. That would get the effective sensitivity into a much more reasonable range and less of the FA503 midrange channel power would be wasted. Tradeoff is a bit more distortion from the T34A. I think this makes more sense (and is more cost-effective) than my original plan of using 2x CSS SDX10s in a push-push config on each side with only 500w to power them, also since I'm crossing at 200, that's a bit high to set drivers facing to the side or back, no?
Thanks again for helping me think this through.
Thanks again for helping me think this through.
The directivity @ 200Hz is fine for monopole bass.
I've taken polar measurements for woofers 6.5-8" outdoors and they are +/-1 dB up to 200Hz. In fact, the +/-1 dB differing could be based on differing distance to the mic alone. Corrected for microphone measuring position it's probably a wash...
Reference:
https://www.htguide.com/forum/forum...nted-woofer-css-sdx10-in-floorstander-designs
I've taken polar measurements for woofers 6.5-8" outdoors and they are +/-1 dB up to 200Hz. In fact, the +/-1 dB differing could be based on differing distance to the mic alone. Corrected for microphone measuring position it's probably a wash...
Reference:
https://www.htguide.com/forum/forum...nted-woofer-css-sdx10-in-floorstander-designs
You can see some modelling in the threads below too, there is some change but it's still quite usable.
https://www.audiosciencereview.com/forum/index.php?threads/woofer-stands-module.33766/post-1178753
https://www.diyaudio.com/community/...oint-source-bem-modelling.386711/post-7034269
https://www.audiosciencereview.com/forum/index.php?threads/woofer-stands-module.33766/post-1178753
https://www.diyaudio.com/community/...oint-source-bem-modelling.386711/post-7034269
I'm using the 26ADC in a 5" Augerpro WG on top of a MW13TX and 2 x SB23NRX. Curious to have a sleek speaker, I found 4 x PTT6.5X04-NFA-01 and thought they could run from 400Hz and down in a closed box... with no high pass, since they have plenty of X-max - thereby avoiding filters, and hereby ease up on the integration with my 4 subwoofers. This works great with the SB's, but I can't really find a difference in sound that I hoped for = cleaner bass (perceptual, I know).
My guess is that the Purifi needs port or passive drivers, to reach lower notes, and that they aim for a driver that plays in smaller 2 ways - doing both midrange and bass well. It seems that a dedicated bass driver needs not be that expensive a a midrange to gain very good percieved sound quality - maybe mostly because of our difference in hearing sensitivity with respect to frequency, and room interaction changing a lot with frequency too.
Adding filters at 400 and 2000Hz and shifting between Textreme and Purifi, playing white noise - really did not add much to my idea of what these two drives does differently. Even though it might be fun to use the drivers I have, to build an MTM with a larger WG, since they do play great midrange, I'm not sure what I'd truly gain.
MTM do add other considerations, and that's why I thought of selling the X-version and getting the M-version to at least gain better sensitivity, even though my active system with lots of power, does open up for many possibilities.
Many people seem to point towards PA drivers for dedicated midrange, since they cost way less and might offer 95% of the same perceived performance. But who made a blind listening test with this in mind? I mean.... a 3 way system, with dedicated midrange with Purifi M vs any 6" at 1/4 or 1/3 the price.
Purifi I believe and experience, are great drivers for their purpose. But for dedicated midrange, it becomes a tight race. Maybe I should use a single of the X-version I have, with a 6" Augerpro and my 26ADC, to see if that clears up some thoughts on what is preferred. I might be suprised.
I bought 6x Purifi PTT6.5M08-NFA-01 for MTM instead of PA drivers for their better SQ. Did I make a mistake? I'll learn early next year when I start building the cabinets. But at the same time I'm still doubting what tweeter I should use? T34B vs high quality ribbon? Or even a horn?
@mainframe99 May be worth updating the front page as Troels Gravesen has modified the Purify 6R by replacing the Viawave ribbon with a Satori Be tweeter, still on a flat baffle.
http://www.troelsgravesen.dk/Purifi-Be.htm
http://www.troelsgravesen.dk/Purifi-Be.htm
I'm just curious what kind of tweeter they intend to release alongside their broad operating range of woofers. Their prototype speaker had a Mundorf AMT, probably to show off the range of the 6.5" and it's clarity up high. There won't be a lot of need for higher sensitivity or less distortion on quality tweeters. The DIY community seems very focused on Directivity lately. I'm sure we'd all appreciate a nice set of easy to use, interchangeable waveguides. It's hard to see a new design making a splash like their woofer category, unless they can get a 1" to play down to 500hz or something wild.
Thanks ugg - I'll do an update soon there are a couple details to add and redundancies.
Friends I need help I have pair 4" Purifi woofer and a 6.5" purifi woofer and some tweeters like ViaWave ribbon used in trovels and peerless corrundum tweetre and Fountek Ribbon also have SB acoustic racetrack PRs. Problem is I dont have skills to make a passive crossover and purifi site there is no MINIdsp OR hYPEX dsp file that I can download. I bought plan from Jospeh crowe but he doesnt have minidsp file. Jansen the people who sell kits is not willing to share DSP
Anyone here who has large heart can share file at least I can load in miniDSP and try fiddling with it. Like linkwitz transform I dont understand how to.
I cannot use paypal in my country ( India) I can swipe my credit card only on proper sites example Joseph crowe. he has shopping cart so
my email id is tigeranand at gmail dot com
currently I only have and own LXmini on my miniDSP 2x4HD but that file configuration is differnt
So if someone can give file for free or at a price but it should be a ecommerce site not paypal
thanks & regards
anand
India
Anyone here who has large heart can share file at least I can load in miniDSP and try fiddling with it. Like linkwitz transform I dont understand how to.
I cannot use paypal in my country ( India) I can swipe my credit card only on proper sites example Joseph crowe. he has shopping cart so
my email id is tigeranand at gmail dot com
currently I only have and own LXmini on my miniDSP 2x4HD but that file configuration is differnt
So if someone can give file for free or at a price but it should be a ecommerce site not paypal
thanks & regards
anand
India
@tigeranand if you have MiniDSP I think you should try setting up the filters yourself. I know that you don't have the skills now, but if you can read a frequency response chart, then setting up a crossover (at least doing the very basics) should not be too hard for you. There are plenty of tutorials out there. Here's an example of one, but there are many others on Youtube:
I don't have a MiniDSP or any files to share, but I think if you have invested enough $$ to have some Purifi drivers on hand, then investing a little time to set them up properly should be doable.
Someone may have files suitable for those drivers, but a crossover depends on the drivers, the size of the enclosure, as well as the size and shape of the baffle... so they tend to be unique. Changing any one of those requires a new crossover. So you are probably going to need to learn this for the parts you currently have.
Take heart, making a crossover in DSP is (IMO) way easier than building a passive one...!
Someone may have files suitable for those drivers, but a crossover depends on the drivers, the size of the enclosure, as well as the size and shape of the baffle... so they tend to be unique. Changing any one of those requires a new crossover. So you are probably going to need to learn this for the parts you currently have.
Take heart, making a crossover in DSP is (IMO) way easier than building a passive one...!
Unfortunately I do not think a great result can be achieved without proper measurements and simulations. It would be a shame not to use these amazing drivers to their full potential. You of course can try, but if the result is not what you expected it to be, have in mind that it may be due to that "approximate" implementation.
PSA, FYI, certain US retailer has the 8" on sale $100 off at the moment.
Even though I was very excited about the 8" before it came out, the current price, even with discount, makes it hard to just go for it.
As for my next project, I am considering some tweeter + Purifi 6.5 in a sealed cabinet, passive crossover, and then match it below with a JBL 15". With active DSP crossover the 6.5" and the 15", around 80-100Hz. This allows me to have very very low distortion at the best of the 2 drivers' range.
Even though I was very excited about the 8" before it came out, the current price, even with discount, makes it hard to just go for it.
As for my next project, I am considering some tweeter + Purifi 6.5 in a sealed cabinet, passive crossover, and then match it below with a JBL 15". With active DSP crossover the 6.5" and the 15", around 80-100Hz. This allows me to have very very low distortion at the best of the 2 drivers' range.
I'm actually curious from those who've heard the 6.5W/X, where does it really excel? It's sold as an all-in-one broad operating range package that can steadily play ~40-4000hz without one band interfering with the other. Is this really accurate? Is it better with a greater low-pass filter in the 100's as a midbass?
Would you accurately state make and model of the drivers you own and measures of cabinet you find suitable for these?
It does not matter how large a container is, it matters the quality of stuff it's filled with! It can be anything.
40Hz to 4kHz might be stretching it. The breakup starts around 2.5kHz.
I have used it sealed 2-way with a few different tweeters at 2kHz. The sound can be described as clean and lack of any sort of distortion. Basically a typical small bookshelf size, yet it can handle my 400 sq ft room for most moderately loud music. The most impressive is that it sounds clean and lack of distortion even as the volume goes up. Usually with other speakers, once cranked higher volume they sound obviously strained. For the Purifi, it just keep same clean sound until it hits xmax and then it dramatically fails. Before then, I am able to play most symphonic music with it. In fact, the sound is so clean I sometimes don't even noticed how loud it is playing.
Having said that, there are still limits. It is a 6.5" afterall, I don't feel as much impact as it does compared to the 15" JBL. And it doesn't handle say a bass drum in a full orchestral piece. And for sealed, it only goes down to ~75Hz or so. I did initially built a PR cabinet for it but pretty sure it was poorly designed as while it did sound decent overall the sound wasn't impressive. One of these days I will try different alignment to see how the Purifi will sound when producing 40Hz.
They also have the Satori MW13TX on sale; also for about $100 off. That is tempting the heck out of me as a mid between my 6.5Xs and T25Bs. I don't suppose anyone has been able to compare the midrange of the Satori TX series and the Purifis. If anyone has, I'd love any impressions.