You're so right Dave--Some folks will just never get it!

Gary

Sorry there is no control of that.

You talk about the Bose L1 like it is half of a stereo system. It isn't, it is a mono system. And is sold that way by Bose. It is not just a matter of economy that people buy them as a mono system. To insinuate that is simply wrong. If I am missing where Bose is pointing out that it is not a mono system please feel free to correct me. Using 2 of them is just a work around. The two sides aren't locked into a stereo image like a true stereo system. It is up to you to ensure the EQ is set exactly the same on both systems. If stereo image is so important you probably shouldn't really be buying mono systems in the first place.

The other thing if that while the cancellation isn't occurring for you where you are hearing the stereo sweet spot it is still happening for your audience that isn't in that sweet spot where the two sides are naturally summing to a mono field. Phase cancellation is an acoustic problem and is not limited to what you are hearing from your ideal location.

Back when AM radio was still big ALL recordings had to be able to be summed to mono without problems. If a recording didn't pass this test it failed.

The problem is not with the mono L1 Bose system...it is a well known issue with the Yamaha arranger, which has phase cancellation when using a single powered speaker system (mono), of any brand.

If I use one powered speaker, of any brand, that is plugged into the Yamaha's L+R (Mono) output, there will be phase cancellation, which in my opinion, as well as many others, is unacceptable.

Some people are able to happily live with that issue, but, in my experience as a Yamaha clinician, most cannot; the only real workaround is to use two powered speakers, or a stereo amp and two speakers.

I never recommend a single amp/speaker system (mono) with a Yamaha arranger, although, I'm sure there will be those who will. I am under strict orders from Yamaha to always use a stereo system when demoing.

It is not strictly a stereo vs. mono issue...it is about Yamaha's well founded phase cancellation phenomenon.

Ian

I agree that the problem lies with Yamaha's unique 'phase cancellation' issue, and not with the Bose L1 or any other mono output speaker units used.
On the other hand, 'mono' samples aren't affected by this effects phase cancellation problem.

I still always insist on going out in stereo whenever possible,
but I've found (but only after upgrading to a Tyros 2 generation arranger and later) going out to a single speaker,
at least tolerably acceptable when going out mono is the only setup option available,
but only if you restrict yourself to playing 'mono sampled' voices.
Here's a thread I posted on this topic back in July 2006:

Tyros2 sounds fine thru a SINGLE mono PA Speaker now!

For those interested, here are some interesting links on the topic of stereo phase cancellation:
Mono Compatibility and Phase Cancellation
Avoiding Phase Cancellation
Mono Compatibility - How Important is It?

Thanks Scott, those links provide some good info.

As for the Yamaha problem I am guessing it is to do with their implementation of the stereo effect processing where the left channel is just a phase inverted version of the right channel. Apart from the effects there shouldn't be a problem with the samples themselves. For example a stereo piano sample should be the lowest key in the left channel rising to the highest key in the right channel. There really should be no problem summing this sort of stereo sample as the left and right aren't phase inverted versions of eachother.

I think a stereo sample with mono effects should sum just fine. It would be worth trying to see.

Nigel,

The only voice in Yamaha's keyboards that seems to suffer from phase cancellation is their grand piano. It has been my experience, and the experience of many, many others that the summing of other, popular voices does NOT have a phase cancellation problem.

Get the hook,

Gary

This problem, according to Yamaha Canada, goes all the way back to the PSR-8000, and mainly affects the Sweet!, Cool!, Live!, SA, SA2, and most mega, voices, and therefore pianos, electric pianos, guitars, strings, brass, organs etc.

It is not merely restricted to the piano voice, although, because it is the one most used, it gets most of the attention.

Attempts at editing voices to eliminate or reduce phase cancellation have resulted in one dimensional, un-dynamic sounds; the ones I've heard could not be deemed remotely useful.

Still, the very well known phase cancellation does not seem to bother a few users...I suppose they are lucky, certainly far more fortunate than their listening audience.

Like you Scott, since my sound is very important to me, using stereo is the only real solution.

Ian