Bose 901...really

Eldartford, I think that your results reflect (excuse the pun)more your room than the overall response of the Bose. In my secondary system where I use the Bose 901s, I did not find the 630 peak nor the severe rool-off in the highs. I did find, however, a +6 db peak at 40 Hz and about a 6db/octave rolloff in the highs starting at about 8000 Hz.

My room is a typical 14 by 12 room with 10 ft ceiling, not the very 'special' room that you are running the Bose 901s. The larger the room, I think, the more the highs will be rolled off.

I am a bit surprised, however, at your comment on the loud bass. What makes you think that the bass is 'overloaded'?

Curious,

Bob P.

Inpepinnovations...The nature of these speakers (reflected sound) would surely make them more affected by the room than most speakers. The response that I observed (without the extra equalization) was a very broard "hump" across the entire audio range (like a Gaussian distribution curve) and had very little in the way of localized peaks and notches. My microphone position was at least 20 feet away from the speakers. I would try it again close mic'd, but how would you do that with these reflected sound speakers?

The bass overload (distortion) was due to the signal driving the speakers. The Bose equalizer boosts the bass, and I was adding another 15dB to get the flat response. The power amp I used for this test is good for 250 watts, so I doubt that it was the problem.

Eldartford, perhaps you are overloading the input to the pre-amp? can you increase the gain on your power amp so that you can reduce the signal necessary to drive the amp. Then the Bose equalizer need not output so much and you can reduce the output from the additional equalizer. But I am sure that you have thought of this and are worried about the noise that might be introduced by this solution.

Also, close mic readings are not want you want anyway. At any rate you seem to have 'tamed' that broad boost with the extra equaliser. Now you just ned to work on the Bose eualizer overloading distortion problem.

Salut, Bob p.

Inpepinnovations...The Bose equalizer comes before the Behringer, so the Bose doesn't have to put out anything extra. And the Behringer has LEDs indicating its input level, which, if anything, is a bit low. (The Behringer has balanced output to the amp).

I guess the 901's can play loud, or have extended bass, but not both at the same time. Hey, what can you expect from a bunch of 4" speakers.

I listened to 901s extensively in the 70s and 80s (mostly discos but some friend's houses, too.) They had no bass and very shelved down highs. The two discos that used them had supertweeters and subwoofers also and used the Boses pretty much for midrange. When I've heard them at houses they've always sounded shouty and veiled at the same time. Phasey, too.

I'd go to your local Guitar Center and check out some pro speakers, both studio and reinforcement types.