Re: Thus Far
Lynn
Thanks for the review. There is so much we agree on and so much we disagree on, its hard to belive that we are both trying to solve the same problem. Clearly one difference is I am always trying to keep the costs down as low as practicable and that doesn't seem like a strong criteria in your approach.
Let me know if you want to try some of my waveguides - with foam - I think that I will have a regular supply coming from Thailand.
Lynn Olson said:
Lynn
Thanks for the review. There is so much we agree on and so much we disagree on, its hard to belive that we are both trying to solve the same problem. Clearly one difference is I am always trying to keep the costs down as low as practicable and that doesn't seem like a strong criteria in your approach.
Let me know if you want to try some of my waveguides - with foam - I think that I will have a regular supply coming from Thailand.
matching....
Fellow diyers and Lynn,
My previous post was not meant to make you use the PHY or PHL speakers. I actually never have auditioned them… I just wanted to have some opinion about the relevance of pairing drivers.
As John mentioned, AE speakers have much tighter tolerances, but the standard within industry is ± 10 %, which is pretty wide!
Chris mentioned that some Danish manufacturers sell pair of their units.
Globally, it seems that very little is done to match the left and right drivers of a pair of loudspeaker. That’s what I call pairing (have in mind that English is a foreign language to me!)
Considering a wide range speaker pair, I have the feeling that a well matched pair of driver will give a better stereo perspective, sharper sound, more 3-dimensional sound. On the other side, badly matched units would give a blurry soundstage. Everything else equal, of course…
The same argument is also valid for several way speakers!
Going a bit further, you can question the relevance of drawing conclusion from a waterfall graph of one and only driver. What if the driver is at the bottom of these large tolerances? What if it is at the top of it? You never know…!
So am I lost on petty details here or am I onto something???
/Etienne
Fellow diyers and Lynn,
My previous post was not meant to make you use the PHY or PHL speakers. I actually never have auditioned them… I just wanted to have some opinion about the relevance of pairing drivers.
As John mentioned, AE speakers have much tighter tolerances, but the standard within industry is ± 10 %, which is pretty wide!
Chris mentioned that some Danish manufacturers sell pair of their units.
Globally, it seems that very little is done to match the left and right drivers of a pair of loudspeaker. That’s what I call pairing (have in mind that English is a foreign language to me!)
Considering a wide range speaker pair, I have the feeling that a well matched pair of driver will give a better stereo perspective, sharper sound, more 3-dimensional sound. On the other side, badly matched units would give a blurry soundstage. Everything else equal, of course…
The same argument is also valid for several way speakers!
Going a bit further, you can question the relevance of drawing conclusion from a waterfall graph of one and only driver. What if the driver is at the bottom of these large tolerances? What if it is at the top of it? You never know…!
So am I lost on petty details here or am I onto something???
/Etienne
Caferacer said:
Ahh, missed that part. This will be a coherent challenge! All these drivers are basically to get rid of the beaming in the higher frequencies...?
I am going to follow this project very carefully because on my OB, I have been suggested to use a compression driver for the upper mid. I am very sensitive to coherence, so adding yet another driver to the mix scares me.
"I am going to follow this project very carefully because on my OB, I have been suggested to use a compression driver for the upper mid. I am very sensitive to coherence, so adding yet another driver to the mix scares me."
Agreed. Plus, I dislike horns. I am rooting for the underdog. I hope the best sound ends up being the 12" hemp cone alnico magnet Tone Tubby(maybe modified with phase plugs) crossed straight to the double high Raal tweeter. That would be cool.
Agreed. Plus, I dislike horns. I am rooting for the underdog. I hope the best sound ends up being the 12" hemp cone alnico magnet Tone Tubby(maybe modified with phase plugs) crossed straight to the double high Raal tweeter. That would be cool.
gedlee said:
I'm certainly open to trying them at some point in the future - but for the present, I'm looking at what large-format compression drivers can, or can't, do, starting with the Altec 288 family and modern successors like the Radian 745P.
The comment about keeping costs down brought a smile - see pix below. That's one channel of a 16-watt Class A amplifier. I didn't design it because I'm into the SET craze - although I'm partial to some of them - but as a research project to see how low I could get distortion in the forward path, with no assistance from feedback or feedforward techniques, as well as investigating a topology that as little variance in dynamic output impedance as possible (as voltage swings up and down, many amplifiers have instantaneous changes in output Z as devices switch on and off).
It might be possible to do the same things with MOSFETs, but they'd require some fairly exotic analog-computer pre-distortion techniques to get the forward-path distortion as low as DHTs are naturally - besides, aside from the charms of a 520 volt B+ supply and the pleasing glow at night, I was curious about the sound of the devices themselves, not the devices + complex pre-distortion circuits. So I'm willing to go out on a limb with these little projects, and if it's out of fashion in audiophile and engineering circles, so much the better.
I like investigating these obscure corners of audio - techniques that fell out of favor decades ago, or were outright forgotten, such as the Western Electric alternative to negative feedback, the Harmonic Balancer, which was partially revived in this amplifier. It was last used in the Western Electric 92A, circa 1935, and was forgotten when the Williamson swept aside all other topologies in 1947.
For some reason, and it really seems little more than historical accident, Hollywood (Altec and JBL) did not follow up on the time-domain research of D.E.L. Shorter of the BBC and Richard Heyser - even though Pasadena, home of Caltech, is only a few miles away from the headquarters of both firms. Probably one of those all-too-typical Not Invented Here things (I worked at Tektronix for nine years, and John Atwood has told me plenty of stories about what it was like to work for Intel, Sequent, and Apple).
Anyway, with computer techniques, we can look at things that should have been investigated many decades ago - and time-domain performance of high-efficiency speakers is right at the top of the list. Will the compression driver & horn (or waveguide) outperform the stacked array of direct-radiator midranges (I already have a quartet of 18Sound 6ND410's)? We'll see.
Attachments
Hi Mr Olson and Dr Geddes and everyone else in this thread! 
I woud like to know Your opinion on this: http://www.niji.or.jp/home/k-nisi/gs-1.htm
Onkyo Grand Scepter
Of course this is not an OB design but I can see some common features with Mr Olson's "Beyond Ariel" project and even more with Dr Geddes' designs. I mean high directivity, high efficiency, high power handling, mighty midtweeter in a big waveguide, no bass augmenting resonators and so on
best,
graaf
I woud like to know Your opinion on this: http://www.niji.or.jp/home/k-nisi/gs-1.htm
Onkyo Grand Scepter
Of course this is not an OB design but I can see some common features with Mr Olson's "Beyond Ariel" project and even more with Dr Geddes' designs. I mean high directivity, high efficiency, high power handling, mighty midtweeter in a big waveguide, no bass augmenting resonators and so on
best,
graaf
graaf said:Hi Mr Olson and Dr Geddes and everyone else in this thread!
I woud like to know Your opinion on this: http://www.niji.or.jp/home/k-nisi/gs-1.htm
Onkyo Grand Scepter
Of course this is not an OB design but I can see some common features with Mr Olson's "Beyond Ariel" project and even more with Dr Geddes' designs. I mean high directivity, high efficiency, high power handling, mighty midtweeter in a big waveguide, no bass augmenting resonators and so on
best,
graaf
The waveguides are way too small to be effective and they terminate in shrp edges - both very bad ideas.
Lynn Olson said:
Lynn
Those companies that you mentioned are just about the strongest NIH places that I have ever seen. They use others ideas and then act as if they thought of them - the ultimate NIH.
Its your time domain ideas that I agree with most since this is where I am finding the strongest correlation with subjective sound quality. Its the nonlinear distortion things that I agree with least because I used to believe in nonlinear distortion, but then as I studied it I found that it wasn't a factor, but time domain stuff was.
And, by the way, you do know that line arrays always have "tails" in their impulse responses - they have to - which means that they can never have compact impulse responses. Only point sources can have a compact impulse response.
Good luck
I have to agree with Earl on this.graaf said:Hi Mr Olson and Dr Geddes and everyone else in this thread!
I woud like to know Your opinion on this: http://www.niji.or.jp/home/k-nisi/gs-1.htm
Onkyo Grand Scepter
Of course this is not an OB design but I can see some common features with Mr Olson's "Beyond Ariel" project and even more with Dr Geddes' designs. I mean high directivity, high efficiency, high power handling, mighty midtweeter in a big waveguide, no bass augmenting resonators and so on
best,
graaf
Additionally, I think that the sphere type baffle that smooths the edges to minimize edge diffraction is very necessary for good imaging.
Dr Geddes,
Are their AES papers or other peer reviewed sources to look at that show:
"And, by the way, you do know that line arrays always have "tails" in their impulse responses - they have to - which means that they can never have compact impulse responses. Only point sources can have a compact impulse response."
Regards,
C
Are their AES papers or other peer reviewed sources to look at that show:
"And, by the way, you do know that line arrays always have "tails" in their impulse responses - they have to - which means that they can never have compact impulse responses. Only point sources can have a compact impulse response."
Regards,
C
gedlee said:
gedlee said:
are they to small?
I surely don't know - so I trust You
but the midtweeter (800 Hz and up) waveguide looks bigger than in Summa or AI-Audio
it's about 60x30 cm
and the midbass waveguides match the midtweeter waveguide and it looks that this was just their purpose, no bigger needed
as to sharp edges - they quite standard, aren't they?
also among horn classic like Klipschorn, big JBLs etc.
I know (from Your posts) that it is very bad idea from theoretical point of view (and I can't argue and don't want to) but apparently not always very bad sound for everyone
in fact quite the contrary - quite a good sound for many, isn't it?
those Grand Scepters also won international acclaim and many prizes worldwide
so perhaps the ideas were indeed very bad (who am I to argue?) but sound apparently not so bad at all though
best,
graaf
graaf said:
those Grand Scepters also won international acclaim and many prizes worldwide
so perhaps the ideas were indeed very bad (who am I to argue?) but sound apparently not so bad at all though
Since I have never heard those speakers I didn't think that you were asking for my subjective response, so I gave you a technical one. As to "we have always done it that way" - what can I say. If you are perfectly content with the sound of those old style horns then go for it. I always found them to have particularly poor sound quality.
The Summa waveguide does not go down to 800 Hz and it would be way too small at that frequency.
If you buy into "international acclaim and many prizes worldwide" as a testiment to good sound quality then you are pretty nieve about how those accolades come about.
It sounds a little like Lynn and I were being baited into an arguement here. If you already liked those speakers so much then why did you ask my opinion of them? If I thought that was the way to go then I would have done my speakers that way.