Greg Timbers Interview

[Champster]

I just found this interview on Erin's Audio Corner on YouTube.
https://www.youtube.com/watch?v=afeTHLLp-EI

[BMWCCA]

Thanks. I'm enjoying it.

Find it hard to believe the expert/host didn't know what an L250 is. You're supposed to do your homework prior to an interview: http://www.audioheritage.org/html/people/timbers.htm

[Champster]

Thanks. I'm enjoying it.

Find it hard to believe the expert/host didn't know what an L250 is. You're supposed to do your homework prior to an interview: http://www.audioheritage.org/html/people/timbers.htm

Agreed. Erin seemed unprepared for that interview.

[speakerdave]

Some highlights for me:

I love it, in the context of the old penchant for Bose-bashing in these forums, that GT seemed intrigued by the basic idea of the BOSE 901 and said that if the shortcomings had been addressed, it could have become quite an interesting speaker. That is: 1) use higher quality drivers; 2) provide some decent-sounding electronics in the EQ box; 3) change the front single driver into a two-way with a tweeter because there is no way to get any decent treble by EQ'ing a five-inch full range.

I liked hearing GT confirm one of my own biases, that tube amps are complementary to compression drivers and horns in some way that has not been fully explained (to paraphrase: because of the differences between the way tubes and solid state devices work).

I liked that he allowed as how he "still" didn't know why some electronics seem to have good sound stage depth and others do not.

I found his description of the 4660 horn design fascinating and also that the same ideas are included in the design of JBL's latest horns.

I have long wondered about the risk of doppler distortion in the Tannoy coaxial, but I had never before seen the problem addressed. He also seemed to suggest that the projecting treble coaxial horn is so fraught it is beyond problematic.

In talking about patents in audio and acoustics, he said that many recent patents have been awarded because of inadequate research of prior art and prior writings (Olsen in the 1920's) and that therefore the patents are not actually valid. He said that at JBL they sometimes thought it better to not patent something because then no one would know about it. He also said they did not try to protect some things they did because they were so expensive no one else would dare try to copy them—like close tolerances in compression drivers that led to yield problems, but making the gaps more relaxed caused frequency response anomalies which could not be remedied other ways. This makes me think of past conversations here about apparently unused drivers that people were buying on eBay.

He has worked to get time alignment and linear phase in his music system. Though he does not say this explicitly, I think that for him these are the persuasive possibilities of digital electronics past the front end sources. I liked that he notes differences in digital music products when that does not seem strictly possible in the digital domain; this is an old conversation between my son and me.

[Robh3606]

I found it interesting that he ditched the Everest cabinets, kept the drivers and made his own cabinets because the Everest cabinet was holding him back! Love to get a better look at the horn he is using and wonder if he is using the 045Be in his speakers. They look cool a stubby L250 like arrangement.

Rob

[Ian Mackenzie]

Glad you guys found this interview. I posted a link in another thread.

Greg 3 D printed those horns. The idea was to line up the sides horizontally with centre under the screen.

On the occasions when l have met Greg it’s his granular understanding drivers and being able to explain exactly what’s occurring in a system that’s truly impressive. For example Greg is able to interpret the limitations of modelling large drivers such as the 2245 and then adopt specific measurement techniques to find the answers. He tells it how it is too.

Greg is a world class loudspeaker engineer.

What l thought was interesting is that Greg adopted an empirical approach to initial testing of system and networks in a listening room early in the development as apposed to predictive modelling using driver data collected in a test chamber. Greg used his ears early on to determine if a system it was going to gel or not.

[DavidF]

I found it interesting that he ditched the Everest cabinets, kept the drivers and made his own cabinets because the Everest cabinet was holding him back! Love to get a better look at the horn he is using and wonder if he is using the 045Be in his speakers. They look cool a stubby L250 like arrangement.

Rob

OK, now, if you watch the camera pan the side wall you will see a woofer looking back at you from within the fireplace. Better use for a fireplace in So. Cal, I suppose.

[Mr. Widget]

Some highlights for me:

I love it, in the context of the old penchant for Bose-bashing in these forums, that GT seemed intrigued by the basic idea of the BOSE 901 and said that if the shortcomings had been addressed, it could have become quite an interesting speaker. That is: 1) use higher quality drivers; 2) provide some decent-sounding electronics in the EQ box; 3) change the front single driver into a two-way with a tweeter because there is no way to get any decent treble by EQ'ing a five-inch full range.

I liked hearing GT confirm one of my own biases, that tube amps are complementary to compression drivers and horns in some way that has not been fully explained (to paraphrase: because of the differences between the way tubes and solid state devices work).

I liked that he allowed as how he "still" didn't know why some electronics seem to have good sound stage depth and others do not.

I found his description of the 4660 horn design fascinating and also that the same ideas are included in the design of JBL's latest horns.

I have long wondered about the risk of doppler distortion in the Tannoy coaxial, but I had never before seen the problem addressed. He also seemed to suggest that the projecting treble coaxial horn is so fraught it is beyond problematic.

In talking about patents in audio and acoustics, he said that many recent patents have been awarded because of inadequate research of prior art and prior writings (Olsen in the 1920's) and that therefore the patents are not actually valid. He said that at JBL they sometimes thought it better to not patent something because then no one would know about it. He also said they did not try to protect some things they did because they were so expensive no one else would dare try to copy them—like close tolerances in compression drivers that led to yield problems, but making the gaps more relaxed caused frequency response anomalies which could not be remedied other ways. This makes me think of past conversations here about apparently unused drivers that people were buying on eBay.

He has worked to get time alignment and linear phase in his music system. Though he does not say this explicitly, I think that for him these are the persuasive possibilities of digital electronics past the front end sources. I liked that he notes differences in digital music products when that does not seem strictly possible in the digital domain; this is an old conversation between my son and me.

+1 on all counts.

Specifically on the 901, the original used the same CTS 4.5" full range speaker that were used in the original Auratones. They were inexpensive little speakers that did not suck... and since there was no crossover with all of the phase shift and other issues associated with a multi-way speaker, there was a certain purity there. The 901s took this in an interesting direction. As GT pointed out using better electronics and adding a small tweeter to the front speakers could have been quite interesting.

It was interesting to hear Greg's openness to unusual designs like the 901s and his discussion regarding the Carver open backed design.


Widget

[rusty jefferson]

...I love it, in the context of the old penchant for Bose-bashing in these forums, that GT seemed intrigued by the basic idea of the BOSE 901 and said that if the shortcomings had been addressed, it could have become quite an interesting speaker. That is: 1) use higher quality drivers; 2) provide some decent-sounding electronics in the EQ box; 3) change the front single driver into a two-way with a tweeter because there is no way to get any decent treble by EQ'ing a five-inch full range....

So, since there's interest in this I'll share an article written by a fellow I met last winter who said he'd been inspired by the Bose 901 many years ago and has been on the path to improve the concept ever since. He'd had many conversations with Dr Bose about it over the years as well as other audio engineering friends.

After reading the article and discussing it with my audio gurus, I thought his system would be just as smeared (or worse) as the 901s but would probably have better dynamics. Our biases poison us. His system fixed exactly the problems discussed about the 901s and created the most natural full range 3 dimensional soundstage accurately placing the musicians across the stage I've ever heard, barring one other system. Any recording of a live acoustic event spanned the entire width of the room (24 feet) and has as much depth and most important, as much imagine specificity as the microphones captured. And the dynamics were through the roof. Like a cinema experience. High sound pressure, low distortion, and absolutely transparent sound. You cannot tell there's even speakers in the room. I was stunned. No smear. Clean and clear, with excellent transients. Not a perfect system, but shockingly good. Most interesting, is that there is no change to the image or soundstage when the center speaker is turned off/on. Just more dynamic headroom when on.

I reached out to him this morning to see if it's okay to share the article. For anyone seriously interested, he's always happy to discuss the design. Let me know and I'll put you in touch. If you're in the area (Tampa) he'll probably invite you to listen to it.

https://drive.google.com/file/d/1YXx...ew?usp=sharing

[Mr. Widget]

Thanks Rusty!

I quickly read through bits of the article and then downloaded it.
I'd like to spend more time with it when I am not on the clock... solving and creating other audio problems.


Widget

[hjames]

I just found this interview on Erin's Audio Corner on YouTube.
https://www.youtube.com/watch?v=afeTHLLp-EI

Very nice! The redesigned Everest speakers were interesting.
I'd like to know what the ceiling drivers were that he refers to with the dual 5" drivers and "toy horns" (mylar-like but not mylar diaphragms) ...

[Mr. Widget]

Very nice! The redesigned Everest speakers were interesting.
I'd like to know what the ceiling drivers were that he refers to with the dual 5" drivers and "toy horns" (mylar-like but not mylar diaphragms) ...

Here ya go... take a look at the wave guide. It is a mini original Everest/S3100 type wave guide.

https://www.jblsynthesis.com/product...d=loudspeakers


Widget
.

[hjames]

Here ya go... take a look at the wave guide. It is a mini original Everest/S3100 type wave guide.

https://www.jblsynthesis.com/product...d=loudspeakers

Widget

Thank you!
Looks like it may be related to the JBL HDI-1600, which is available in a walnut finish
https://www.jbl.com/bookshelf/HDI-1600.html

and also uses that 2410H-2 1" compression driver. (Greg said it had mylar-like but not mylar diaphragms)
At $990 a pop, price is approaching the $1,100 InWall Synthesis SCL-7s ...

[BMWCCA]

Looks like it may be related to the JBL HDI-1600, which is available in a walnut finish
https://www.jbl.com/bookshelf/HDI-1600.html

Wow! Those little suckers are nearly a thousand-dollars each.

[DS-21]

Here ya go... take a look at the wave guide. It is a mini original Everest/S3100 type wave guide.

https://www.jblsynthesis.com/product...d=loudspeakers


Widget
.

Are you sure? He said they were from Pro and used the same compression driver as his 5-series.