Wanna hear your soundstage walk around ???

Courtesy of Bob Bundus, i was able to see just how much "image shift" i've been experiencing. Remind me to "kick him" next time i see him : )

Bob was kind enough to lend em a disc put out by Ayre Acoustics entitled "Irrational, But Efficacious !". If i recall correctly, he picked this up from Bes at Music Direct but i'm sure that other Ayre dealers may have it in stock. You can also probably pick it up directly from Ayre at www.ayre.com

This disc has several different types of noise patterns ( white, pink, brown, mono brown, out of phase brown, etc...) on it. You can use these for various aspects of setting up a system, testing components, etc... It also has two "Glide Tones" on it. These are actually full audio spectrum "sweep tones" that start out at 5 Hz and climb to 20 KHz at a gradual rate. One is of short duration ( 45 seconds ) and the other is appr 4.5 minutes long. Ayre recommends using these "glide tones" occasionally as they supposedly "clean out" your system. If i recall correctly, i think that Cardas also has some discs to this effect ( Cardas Sweep ??? ) as the Ayre disc gives special thanks to "George Cardas, the ever curious audio explorer".

There are several very "neat" things about these "glide tones". First of all, they start out VERY low in frequency. I was amazed that one set of my speakers was actually reproducing the 5 Hz signal at high amplitude as soon as it started playing. This sounded like the flutter that you hear from a helicopter approaching. The driver was making MASSIVE excursions to do this. As such, i don't recommend playing this disc at any type of volume as it may do damage to your speakers or amp. I contacted Ayre about this with some other questions and they too suggested playback at reduced volume.

However, being the "audio geek" that i am, i couldn't resist turning up the power quite a bit. The effect that this generates at volume is pretty incredible and WILL shake your house and the contents IF your speakers and amp are up to the task. Obviously, the faster your speakers roll off in bottom end, the less output and "impressive" this would be.

In the first system that i tested, i was actually able to drive my amp into SEVERE clipping. It is the first time that i have EVER heard this in my life. The amp in question is rated for 200 @ 8, 400 @ 4, etc... so it is not a "gutless wonder". The speakers in question are rated at a nominal 4 ohm load but i know for a fact that they dip well below 2 ohms at low frequencies. As such, they have been a good test for many amps. Some well respected makes and models have failed miserably with these speakers for obvious reasons.

The sound produced when the clipping took place was similar to the "snap" or "pop" that one might hear on a very dirty record. To get the same effect that i heard though, you would have to drop the frequency of that "pop" down quite a bit and make it much more intense i.e. more of a "CRACK" sound. It was not the speaker itself bottoming out, as i've had that experience before. This happened at two different spots in the frequency range and was consistent, as i repeated the test a few times. I did give the driver time between tests to thermally "heat down" though, as i didn't want to cook the voice coil. As such, the speaker is obviously pulling MUCH harder on the amp at those specific frequencies due to impedance / reactance and the amp simply couldn't keep up. Scary and interesting all at the same time : ) I was able to find out one thing though. This amp had "instant" recovery as you heard the "crack" and the tone kept playing with nary a waver or flutter on either side of that frequency.

Secondly, you can check how linear the output of your system is. As the tone rises, you will hear different levels of output from your system. This demonstrates that you DO have more than a few peaks and dips due to standing waves and reflections in the room. Obviously, the most noticeable frequency "should" be the point of resonance of the woofer resonating in your room, but this may vary if you've got REAL problems with room reinforcement / cancellation nodes taking place. Unfortunately, the tone is of continuous output and ever rising, so there is no real way to judge "exactly" what frequencies are "nulled" or "peaked". One could do this with a calibrated disc of test tones or by using an spl meter and a tone generator in similar fashion to what this disc does.

The next "neato" ( am i old or what ??? ) thing about the "glide tone" is the effect it has on imaging and soundstage. Due to various nodes and points of reflection in your room, you can literally hear the placement of the sound "walk around" your room. Depending on how well the room is acoustically treated and the radiation pattern of your speakers, this can range from interesting to phenomenally "weird". Since i have various types of speakers ( 360* omni's, large towers, horns, etc...) in different systems, this in itself was a rather unique learning experience.

As a general rule, i was able to hear the signal shift from side to side, between the speakers, WAY above and outside of either speaker, etc... as the pitch varied. Since the signal is on a continuous climb that never stops until the end of the track, you literally hear the point of least cancellation racing from place to place.

This in itself is a phenomenal test for room acoustics. For those that think that "room treatments" aren't important, think again. I'd like to see a system / room that could hold the image centered, as it would have to have one HELLUVA lot of work into it.

If it wasn't SO dissapointing to hear how "off center" many of these images were, it would make one helluva "sonic demonstration" to people just entering the hobby. This could INSTANTLY demonstrate what "imaging" really is and how sound can be "focused" or projected into specific areas. Of course, it would be MUCH better if this was happening under "controlled conditions" and not just at random due to "room bounce" : )

If this has been interesting to read, believe me, it was even more "fun" and "educational" first hand. I can't guarantee that you'll have the same results that i did ( hope you don't ), but this disc was able to show me that i need a LOT more attention paid to room acoustics and speaker placement. Then again, you might NOT want to experience this first hand, as you may want to commit "hari-kari" if your results were like mine : ) Sean
Great thread/post Sean. Is it record length for you;>) And when I get up the nerve, I might look for the Ayre CD you describe. Cheers. Craig
Very interesting. I just left a message @ a local dealer to check the price. I would like to use this as a tool to Beta test some PC's that I am currently breaking in. Might be fun to use it with both my personal cables and the test batch to see if it further documents the "musical" characteristics of either. If it's expensive though I will pass.
First off, Sean really had me worried! Just as I got into work today my desk phone was ringing & it was Sean asking if I had read this post yet? I hadn't yet seen it, but from the tone of his voice I just knew that he had blown something up with that glide-tone track. So I'm happy to learn that didn't actually happen because it would be easy to break something with this CD if you're not being careful.
Now the cost: only $19.95 from Music Direct; I believe they're having a special right now but I don't know the list price. Just contact Bes at amusicdirect.com And yes this makes for a great breakin disc too.
I had the same experience re: "resonance circus" it was very interesting to hear all the nodes nulls & other acoustical problems going on within my room. At one point the mirror over the fireplace really got going but the most surprising & noticable resonant peak came from the front door; it seemed just about to come unglued. This glide track will really help you to localize any problems in your listening room. I also noticed image moving around all over the place & discovered that I'm sorely in need of some further room treatments.
I also experienced an interesting improvement in the sound of the system after running that glide tone. Ayre explains that running this track somehow helps to "degauss the residuals" (or some such thing - I can't read the CD's label right now because it's at Seans' house). Whatever it does it definitely does well, because the system sounds somehow overall smoother & cleaner now. It's hard to describe this effect in words, better to just hear the results for yourself. Even my wife noticed the improvement immediately. The instructions advise to run the track about once a month as a maintenance tool & I definitely plan on doing just that.
This disc also serves as a great diagnostic tool with its various noise tracks. For the low cost I'd say that Ayre has a real winner, although I doubt we'll see this one on Billboards' Top 40?
I thought the snap in the frequency sweep was something else. I hear two of these pops (snaps) when I play frequency sweep. I guessed that those were the frequencies where speakers were crossed over. The sound is most evident at higher frequency. I thought it sweep was going from my midrange to my tweeter.
Crazyconnell, now you have me wondering. I only experienced this "cracking" on my one system and it was at low frequencies. As mentioned, i had the volume up WAY too loud when this took place, so i assumed that it was "system overload". It can't be anything related to crossovers in this system, as each cabinet houses one full range driver. The speaker cables connect directly to the driver with nothing to interfere with the signals. Coincidentally, this is the same system that was reproducing the 5 Hz signal at high amplitude ( compared to my other MUCH larger speakers ).

As a test, i just played the disc again on that same system at a reduced level and there is no "cracking" to be heard. Replaying it again at increased amplitude brought back the "popping" or "cracking" sound. Maybe your amp is "having a fit" trying to load into a reactive crossover point ??? Sean
Just for interest's sake, what are the makes and models of the amplifier and speakers to which you refer in your original post which experienced the "cracking"?

A local dealer had loaned me the cd to try. It did seem to clean out the pipes a bit.

Ray, the "cracking" took place in my "computer room" system. I'm currently running a Robertson 6010 ( 200 / 400 ) driving modified Ohm F's. Speaker cables are currently Nordost. I was running a pair of Kinergetics KBA-202A Platinum Mono-blocks with Goertz MI-3's to the Ohm's ( 250 / 500 / 800 ), but took the amps out of the system to do some upgrades / modifications to them. As soon as i can get the mono-blocks done, i'll be ripping into the Robertson.

Other than this one "weird" experience, i've never had any complaints about the current combo. I had run into problems with other amps going into clipping with these speakers, but never this severe. The worst offender previous to this was a Bryston rated at 250 / 400. It would clip just trying to listen at "normal" ( for me ) listening levels playing "regular" music ( not test tones ). Needless to say, out the door it went. I know that it was not faulty, as it had just come back from their U.S. repair facility and had met spec with flying colors.

To be fair though, i have had an amp in here that had very fast acting power meters on it and it was showing dynamic peaks of well over 900 watts into these speakers. If you aren't careful with the volume control and the type of music that you play on them, they can EASILY suck an amp dry. As such, they are not an "every day" speaker for use with "every day" type of amplification. That is probably why the people that had negative experiences with this speaker obtained the results that they did. They are extremely finicky and require a LOT of TLC to get the best out of them that they can do. Once set-up right with good gear, you will never hear a deeper or wider soundstage in your life. Sean
Heh, if you like listening to sine waves check out the group Pan sonic. (nee Panasonic; Matsushita wasn't happy)
Anyway, I got an idea one day. I hooked up an old toy Casio keyboard (SK1, good for circuit bending) and messed around for a while. The cable wouldn't reach back to my listening seat, but I could still really hear the room. The up side was I could control the pitch and hold it, and I don't think it really matters that the closest you can get to a sine wave is the flute. It's a good way to track down rattles and resonances.
The local dealer did not return my call and I was unable to locate the CD @ Music Direct. Does anyone have a link/address for the online sale of this item? Thanks.
There was a CD from a collaboration of XLO and Sheffield Labs, circa 1994, which also had a glide tone on it. Actually two tones, splitting the frequency spectrum. Shorter in duration than the long one on the Ayre. I found it to be sometimes quite effective in clearing out the cobwebs, as is the Ayre (which of course I also bought).
Here's that link for it at at music direct:


I think I need one, too...
Thanks for the link Mezmo, just ordered one.
You bet. So did I.
sean. another remarkable forum from you, and a rekindling of my interest in sweep-frequency tests of enclosure performances. Of course, it would be desirable to employ a dual-trace oscilloscope with a microphone, so that the test signal waveform can be compared to the output waveform from the microphone. An ideal enclosure/listening room would then produce a sound-output waveforem that has the same shape as the test-signal waveform. Of course, departures will always be noticed in the vicinity of the speaker's self-resonant frequency, crossover frequerncy, or because of residual resonances. Although this type of test is very helfpul, it does not provide transient response data. Does the Ayre disc have a tone-burst test as well? A sweep-frequency test can only provide steady-state response data, whereas a atone-burst test provides information about transient response--where the liveliness and vitality of music resides.
Slawney took the words outta my mouth. I visited EAW a few years ago and witnessed their high SPL tone burst measuring tests and was impressed with what these guys were doing: getting the room out of the equation when testing speaker response.
No, there are no tone bursts on this disc. As i mentioned, this disc is worth the cost just to check out your room acoustics / speaker placement / soundstage & imaging capacities. If they gave us everything that we wanted on one disc, we'd never have to buy any other "calibration" discs : ) Sean
Oh my god. Not only did it walk all around the room, it literally pulsed and throbbed at points. Man oh man do I need some serious room treatment.
HAHAHA.... Kind of amazing, isn't it ? It was almost like i had a pinpoint "ball of sonic energy" floating around the room on one of my systems. It was almost as if i could literally reach out and touch where the sound was emanating from it was so concentrated. This varied from place to place as the frequency sweep rose. Obviously, i think that we've ALL got a lot of work to do on our rooms after hearing this disc.

One interesting thought: the next time you go to an audio dealer, take this disc with you and listen to the sweep before auditioning anything. It will tell you ( and the dealer ) just how "good" or "bad" their "reference" system really is : ) Sean