Comments on: The Rational Audio System

By: Ian

Ian — Sat, 22 Oct 2016 11:09:38 +0000

You mention the off axis response. Are you familiar with the extensive research the Harmon KArdon group has done on what makes a speaker sound good ? If not then you should read up on it. In a nutshell, a smooth off axis response is key. BTW, I am totally persuaded by the DSP active approach. I have a pair of JBL M2s but using my own amps and miniDSP rather than the Crown gear that JBL suggest. Many music industry professionals have declared that these are the best speakers they have ever heard. They are extraordinary.

By: Richard Thompson

Richard Thompson — Sat, 14 Mar 2015 11:51:46 +0000

Hi Paul. I actually wrote a longer version of this article (or more “long-winded” as someone has said!) here: https://therationalaudiophile.wordpress.com/2014/08/10/what-price-the-truly-rational-audio-system/

I mention Bud Fried as one of several speaker designers whose design philosophies all seem at odds with each other. I read an article he wrote here: http://www.friedproducts.com/Bud%20Fried/WhatAboutLoudspeakers.pdf

In two fundamental ways, my system differs from his ideas. I use sealed woofers which he regards with “near hatred”, and he doesn’t think much to active speakers, either. However, I think he was writing before DSP was possible, so maybe he would think differently today.

I would be fascinated to see your measurements when they are available.

By: Paul Hildebrandt

Paul Hildebrandt — Fri, 13 Mar 2015 00:29:29 +0000

Sometime in the early 80’s I was wandering the halls of the Hilton listening to the high-end audio exhibits at the Summer CES in Chicago. There was beautiful sound coming from one room so I went in and listened. The exhibitor turned out to be Bud Fried, of whom I had then never heard, and the speakers were called, I think, “super monitors” They look very much like your speakers, and can be seen in the pictures Google produces if one searches for “fried speakers”. They then cost about $3300 for the pair – well beyond my budget. But Bud sold a kit for about $1100, including everything but the wood. I bought the kit and built the boxes and still use the system. Fried put great emphasis on phase linearity and took great pains to achieve it. There were not the computers and other technology available today. The first-order crossovers are obviously hand built. The system sounds good; one can listen indefinitely without fatigue. Recently I decided to get some software and a microphone and make some measurements (which is how I came upon this site today). If and when I get them measured Ii will share the results, good or bad.
Meanwhile, I’d like to build a new system using your guiding principles but with infinitely baffled speakers built into a wall which is unfinished on the other side. I haven’t studied this arrangement yet and I’d welcome any thoughts you have.

By: Richard Thompson

Richard Thompson — Wed, 11 Feb 2015 20:42:15 +0000

It’s a fair point, but my view would be that if they’re selling them to recording studios then some pretty hardheaded people must consider them good value for money. They do amazing things in terms of maximum output level and distortion and they are being sold on their specifications (and certainly not looks!). Whether or not they would be a sensible purchase for the average audiophile is a different matter! I would certainly be curious to hear them, though.

By: Doak

Doak — Wed, 11 Feb 2015 16:24:29 +0000

The Meyer Sound X 10 monitors are priced at $21K EACH.
Can $42K for a powered speaker system qualify as “Rational”?

By: Richard Thompson

Richard Thompson — Tue, 10 Feb 2015 07:40:56 +0000

Hi dubkarma, and thanks for the comment.

Wow. I just looked at your speakers and they’re amazing! I don’t think I would ever turn them up past a fraction of their maximum volume – and I’m a fairly loud listener.

I liked this quote in the SOS review of them:
“…it is as if the control-room window has been removed and you are listening to the acoustic sound in the studio itself. “

By: dubkarma

dubkarma — Tue, 10 Feb 2015 00:06:41 +0000

My active speakers are commercial products (Meyer Sound Labs X-10T), but they seem to fulfill your requirements: 23 Hz to 17 kHz +/- 2 dB with linear phase filters, superb impulse response, 1825 watts/channel of onboard amplification (1200 to the 15″ LF driver; 625 to the HF horn), on-board EMI and RFI filtering, and capable of both supreme delicacy and extreme power (125 dB continuous with 136 dB peaks) as required. However, each cabinet requires its own 15A dedicated circuit. Detailed technical information on the manufacturer’s website (meyersound.com)

By: Richard Thompson

Richard Thompson — Mon, 02 Feb 2015 15:40:13 +0000

Hello Ben. Thanks very much for your comment. Please don’t run away with the idea that I have very fine carpentry skills! In fact I merely made new baffles to screw onto the front of existing ‘donor’ speaker enclosures (some Goodmans from 1969, and some AR from the 1980s). These cost less than the price of raw MDF, and I think there is the potential to actually make such a hybrid enclosure look quite attractive (which I obviously haven’t done yet!).

With regards to DSP there are some free convolution engines out there (BruteFIR?) and this looks as though it could be just the job:
http://thuneau.com/allocator.htm

Sigma Studio (Analog Devices) looks very interesting – I haven’t seen that before. I haven’t yet looked into MinDSP in any great depth, either, but it does look very interesting and reasonably-priced.

By: Ben

Ben — Mon, 02 Feb 2015 13:32:51 +0000

Dear Sir: thank you for a “rational” DIY piece. Your carpentry skills far exceed mine, as do your programming skills. It is on this last point I would like to add my comments. Your overall goals are excellent (to make the best, most tweakable system for the least cost). However, very few people will have the know-how to code their own DSP. Even for old folks like me who may have a CompSci degree but never coded anything harder than a small BAT file or a Unix shell script, may I suggest hobbyist-friendly no-programming-required DSP solutions? MiniDSP is one I’ve used (learned of it on this web site in fact) and very flexible. There is also Sigma Studio and no doubt others. One point your article makes and I’m probably paraphrasing: the tools (cheap hardware and software) exist for the hobbyist to create a unique system, but it does require learning a bit about the tools. After all, the hacking, tweaking, adjusting is part of the system creation process.