LIVE! with PURIFI Co-Founder Lars Risbo!
Вставка
- Опубліковано 25 сер 2024
- This episode I am joined by PURIFI Audio co-founder Lars Risbo. Join us for an open Q&A regarding the tech behind PURIFI's unique transducers plus a quick view of their in-house analyser, built as part of their R&D.
Some background on Lars:
Pioneered direct switching PCM-PWM audio amplifiers as founder of Toccata Technology, later acquired by Texas Instruments. Elected TI Fellow (2012) and Audio CTO (2013). Research interests include digital signal processing, system-level and signal chain optimization, oversampled data converters, transducers and mixed-signal architectures. Ph.D. from DTU (1994). Holds more than 30 US granted patent families.
Chapters and Notes graciously provided by DIYaudio member Norman Tracy:
8:51 - Question “How does a transducer work..?”
19:36 - Lars discusses why speakers are not ideal.
24:00 - Discussion of pole piece iron attraction square of current effect, rediscovered from 1949 research, yields understanding of Force Factor Modulation.
27:00 - Reveals publically for the first time Neo magnet in magnetic circuit to address Force Factor Modulation.
29:00 - “Iron hat” element finishes linearizing the magnetic circuit.
30:40 - Erin asks what are the audible effects of the BL linearization elements in the Purifi magnetic circuit?
37:00 - Discussion turns to the “big surprise” of the hysteresis distortion of iron “the grey dull background”.
39:55 - Shows the copper shorting rings used in PTT6.5W and discuss their functions.
44:25 - Begin discussion of cone, surrounds, and other ‘soft parts’ optimizations.
46:27 - Erin asks question beginning discussion of Purifi’s very unique surround. Lars begins answer with Christmas disappointment anecdote about how after making major improvements in magnetic circuit and motor hoped for distortion reduction ‘barely moved’. This led to investigations into distortion contribution by the surround flying under the radar. Again this led to rediscovery and use of research industry previously ignored.
57:08 - Venting of the motor assembly discussion.
1:01:00 - Spider and slightly progressive suspension, priority of IMD reduction vs. THD.
1:05:00 - Purifi’s custom lab test rig discussion, first demo suffers Murphy’s Law of demos.
1:12:00 - Taking question break while tech glitches are sorted.
1:16:00 - Tweeters can be helped, Purifi tweeters are further into the future.
1:20:00 - Introduction of founding partner Carsten Tinggaard, Co-Owner (PURIFI Transducer Technology) former CTO of Peerless, Vifa, and Scan-Speak when the brands were all part of Tymphany.
1:24:00 - Demo of Purifi’s in house developed measurement system retry & success (loud test tone at 1h26m38s) after tests run results graphs are discussed.
1:39:00 - Lars’ son asks an insightful question.
1:43:00 - Erin asks about drive unit break in.
1:51:00 - New Purifi amp modules coming? Wrap-up, thanks, and goodbyes.
It's very rare that people working on cutting edge technology will take the time to chat about what they are doing and share their insight and process with the public in this way. Thanks so much to the team at Purifi for taking time from their R&D to inform us. Big thanks to Erin as well for creating a forum for such discussion and enlightenment to take place!
Well said, Tony.
Not only that, how many other companies offer the exactly same products to DIY's as to other companies. Lots have improved or higher power version's that the public can't buy (especially with amps). Bruno said in an interview that DIY's will always be able to buy the same quality stuff from them except for some versions with only cosmetic changes.
@Erin's Audio Corner
@Bruno Putzeys
@Lars Risbo
Well, I was definitely disappointed that I was not available to watch this live stream, but I'm sincerely grateful for everyone's time and energy, and the excellent information that was presented and shared!
Big thanks to Carsten as well. What an amazing team of engineers and breadth & depth of combined knowledge!
It's great to hear from the actual engineers that are developing these next-level products. 👍
And I hadn't previously known that Lars is a cellist, so that was revealing, especially in regards to his passion for music and to his criteria and performance goals for their products.
Cello is one instrument that I always focus on when listening and judging the realism and accuracy of any playback system.
It has such an incredible range, and the cello's resonance, complex harmonics, dynamics, and subtleties are not easily reproduced.
So when I hear a recording of a cello that is truly life-like and reproduced realistically, it always gives me goosebumps and joy.
IMO, it is incredibly important when developing any audio product to have that real-world reference to EVERY other live instrument in the orchestra that Lars has, and how those instruments sound & interact as a whole, including the influences and ambience of the concert hall.
So needless to say, I'm thrilled that Lars is involved in the development and testing of the Purifi Audio drive units. :-)
There is obviously some amazing, important, and unique R&D (and fantastic products) coming out of Denmark's Purifi Audio! 👍
I would also love to see some car audio specific Purifi drivers with a focus on compact baskets/frames, mounting flanges, and motors, to accommodate and address the tight space & mounting depth limitations in a vehicle, as well as multi-channel *Purifi Eigentakt* car audio amplifiers come to market! ;-)
It was also interesting and great to see Purifi's and Lars' focus on the hysteresis in/of the driver's magnetic motor system. :-)
Some of the most impressive loudspeakers that I've heard to date were the *Børresen Acoustics 05* floorstanders by fellow Dane, Michael Børresen, whose proprietary drivers are also designed to address the negative effects of hysteresis in the magnetic motor system.
Many thanks again to Erin, Lars, Carsten, and Bruno for the time and energy taken to produce this video. 👍👍
P.S. Lars, if you have a moment, if you could recommend just ONE orchestral recording that you use for both listening enjoyment AND as a testing/demonstration reference, what would it be???
thanks bb. It is quite a challenge to find good symphony recordings. I prefer simple A B stereo with no compression. Unfortunately, most recordings add spot mics and compression. The old Decca recordings were really good but of course technically dated. Reference Recordings did great stuff. Bruno and I have plans for doing some recordings some day - where we are in 100% control of the signal path including converters and decimation filters etc
@@larsrisbo2293
Thank you. I have quite a few of the Reference Recordings as well as Decca releases which are arguably some of the best available.
I'd definitely look forward to hearing your recordings if & when you and Bruno are able to produce them!
Can I also ask what ADC/DAC units you are currently using? I use the Millennia HD-3D-8 and AEA RPQ2 microphone preamps in my home studio, but need to invest in better ADC & DAC.
I'm hoping to build some new studio monitors using your drivers as well, but will wait a bit for your newer developments to be released. I had previously been in contact with Claus in regards to ordering your PTT6.5W04, the newer 4", and inquiring regarding the potential for the tweeter as well.
Thank you for taking the time to respond, and keep up the great work at Purifi. 👍✌
What a great insight into what it takes to create what IMO amounts to a revolutionary driver technology. Thanks Erin and Lars for making this happen, and much appreciation to Carsten and Bruno for participating.
I cannot wait for a purifi tweeter!
Erin does it again. Man this is such a great time for audio. We get to listen to the people behind the magic curtain.
One of the most interesting videos i have seen on audio subjects . And a remarkable lack of the usual bullshit audiofiles come out with !Well done all concerned . Would love to work in that lab !
Great content, exceptional channel.Thanks, Erin and Lars!
thank you
Thanks Erin and Lars, this is the most informative video about driver design I've found. The purifi 6.5 excels at every measurement I've seen. One thing I haven't seen is a waterfall decay plot (CSD). I imagine it would do well since there are no peaks in the frequency response.
Lars dropped so much knowledge here. I still go back and watch bits of it just to try to retain what he said. lol.
As for the CSD data: Since I provide the on/off-axis data, I generally don't provide CSD, too. But I will keep it in mind in the future.
Its on another review site
This is a great interview / Stream. .. Thanks for hosting this =)
Glad you enjoyed it!
Incredible!! Between Lars and you Erin I was waiting on every word! I am super excited at their work and my jaw dropped when he put a neo magnet in the center of the ferrite instead of the usual iron core backplate/T-yolk. Keep up the good work!
Man, me too! I had so many questions I wanted to ask but didn't want to sidetrack the conversation.
Great stuff. Enjoyed this from start to finish. Thank you all.
Thanks for watching. Lars was a great sport to come on and talk audio and help us all learn.
The Purifi modules are insanely efficient and sound great. Sound quality is night and day ahead of mediocre ICE modules which is what most think of with class D amps. When you have an amp at the top of the mountain for both SQ and measurements the contrarians should pause for reflection.
Of course his english is good, he's from Denmark. Denmark, Sweden and Norway, with languages nearly close enough to be dialects, a total population of just over 20 millions, not really part of a language group beyond thos three countries, and as Lars said a serious need for communicating with the rest of the world. And all three countries have solid public education through high school, and then free or nearly free colleges and universities. And, try studying more or less anything at university level without english. Oh. And did I mention TV? Movies? Pop music? :D
"Loud speaker distortion matters.", certainly Paul Klipsch agreed!
it was nice hearing from Lars, i have a purifi module nad amp so i support his company.
i hope in the future that the diy part selection grows, right no it's just that one crossover kit for the two driver 2way.
what's the thoughts on 2way MTM? as far as i know the benefits of that design and the low extra cost is worth it. on top of that make it sealed cabinet and it is even better.
awesome
Wow this is dynamite. I did not know that they do drivers. I am very impressed by their amplifiers. And now I have looked into their drivers and i am blown away.
Some day when I have time then I could build their 2way that they have drawings of.
And their high quality crossovers!
So their latest amplifiers + build 2way + their great crossover. Could probably be the end game..
I DIYed these into a popular brand of speaker/cabinet/tweet, took about a month to get it sounding great. I didn't like the paper radiator, it was way too sterile sounding, but they make an alum so I'm going with a hybrid.
Any idea if there Are there any plans for a larger sized woofer?
Ive heard great things about the Purifi 6.5's, but my custom interior build revealed alot of space in my kick panel area to run up to a 10" diameter woofer with 5" of depth.
I would love to take advantage of what I've made available.
hi, we have a 10” in the pipeline, cheers Lars
@@larsrisbo2293 thats great news THANK YOU!
@@larsrisbo2293 I was saving up for some Focal 6.5 speakers but after this video i'm going to wait a week or 2 and order purifi.
I'm going to give your company a chance after this interview. You seem like you have a passion for audio and also technical knowledge to back it up.
I'm a big fan of Focals es165kx2 (I've had them on every single car i've ever owned and even a home theater system) and if this sounds even HALF as good as their 6.5 driver then you have a loyal customer for life.
I am still exploring what would be a good Purifi based OB
I'm just thinking how they assemble the motor, since they have Neo magnet in the center of pole piece and big external ceramic magnet that has to magnetized once everything is put together. 🤔
Lovely sound 🤣, 40V really 😲
"... So you don't have garbage in - garbage out ..." Yes QC often isn't great in some of the products I tried and they weren't always the cheap ones. I wish repeatability of the final product was more prioritized.
You seem to be knowledgeable regarding this topic .. what speaker drivers do you suggest ? Is it true the outer magnet the composition and the rarer and more expensive magnets react quicker. So much to learn..
Great Video though very high level technical hope the Q&a could had been addressed more
Yea, I wish we could have answered more but there are only so many hours in a day. It was approaching 8pm his time and I didn't want to ask too much of his time. Hopefully Lars will be willing to come back on and we can have a longer Q&A session.
@@ErinsAudioCorner hecould had gone home 1hr late afterall we are investing in his products and sadly no plans around anywhere on the internet
People are buying drivers but no one is publishing it
@@anandshah71 he was already at work multiple hours after his normal time.
Is that an 8" woofer I see clamped in the test rig behind Lars? I would like to see an 8" version of this driver.
1:50:00 I saw this also in some Chinese earphone transducers - all magnet motor.
It is interesting that the voltage of the amplifier 'causes' the current to flow. The current of what? Answer, the current of the _amplifier._
So we are listening to, not the fixed voltage, but rather the current which the load can take anywhere. The key here is the _quality_ of the driver to draw linear current from the amplifier because that is what we end up listening to. But any 'impedance modulation' will indeed modulate and mess up the current of the amplifier. We are never directly listening to the voltage of the amplifier, only if the driver would be like a resistor (impossible), only then does voltage and current line up. But in the real world, this is not the case. Once again, the key is the quality of the driver and there is no substitute, there is no short-cut.
thanks! excellent point you made
@@larsrisbo2293 Any information about Steinway Lyngdorf integrating the Eigentakt in the next iteration of speaker systems ? What do You think about Klinger Favre ? Thanks.
🇩🇰🇩🇰🇩🇰🇩🇰
HD Audio , but disaster HD video !! very low quality camera in 2021 !!