Matthew J Poes
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I was trying to get some measurements of my living room acoustics to use for a point of comparison. I decided to take a full set of measurements and make a comparison to the speakers as well, just to see how bad the Acoustimas system is.
Of course anyone who really knows Bose knows a few truths. First, they put a lot of engineering into their products, and love them or hate them, you have to admit they squeeze a lot of sound out of small packages. I've generally found their sound to be pleasant for background listening, but unable to really get loud without sounding harsh. In addition, I've noticed that the older bandpass subs have some distortion issues, namely some "honking" problems. Sure enough, you will see those in the measurements.
Anyone remember the old saying, "No highs, no lows, it must be Bose!" Well I can tell you right now, my measurements don't really bear that out too much. They don't have extension to 20khz, but they really do extend high enough to be decent.
Now for the frequency response:
As you can see its a pretty flat response to about 6khz and then begins to roll off. It still has extension out to 13khz, but rolls off a good amount after that. The highs are certainly rolled off, but I also measured from my listening position, and was not on axis to the speaker. It may measure better on axis. The speakers are mounted above the tv which is part of the challenge. Still, a no speaker with that angle would not likely show so much roll off. however, what I find interesting is that this speaker has solid extension down to 35hz. When you consider the total volume of this speaker, that is pretty impressive extension. Sure there are any number of small high end subwoofers from Velodyne, Carver, Sunfire, etc. that could probably match or better than number by a bit, but remember: This was from around 1994 (those didn't really exist yet) and it cost around $500 total (which is about what just the subs cost when they came out). So I will just say, I'm impressed with its bass response.
Ok now lets look at the Distortion. Again, I was actually pretty impressed by the distortion. The high frequency distortion is likely a sign of clipping, nothing to pay attention to, just a measurement artifact (not amp clipping, signal clipping).
Do you see that spike at about 208hz. That's what I was calling bandpass honk. It isn't a port resonance in the obvious sense. This is an 8th order bandpass so they can sometimes have resonances that show up like this. My much larger theater bandpass subs do the same thing, just at a MUCH higher level. That measurement is calibrated against a Level 2 calibrated SPL meter (and NIOSH tests show it meets Level 1 accuracy). That means this has a spike in the distortion at just 72db's output or so. That IS audible, and with low male voices, can be distracting. Now I'll admit that this subwoofer, being so old, could have something wrong with it. I intend to take it apart one of these days to investigate, but given that there is no issue anywhere else (and that I see this with other subwoofers of similar design), I'm inclined to consider this fairly normal behavior. Otherwise, that distortion level is pretty low.
I've also included a measurement comparison against the theater. The volume levels are artificially matched, I took them at two different levels. This is basically my Gedlee speakers and subs against the Bose in a treated theater vs totally untreated living room.
Clearly the theater is better, but honestly I was impressed the Bose measured as well as it did. I expected higher distortion levels (beyond that spike) and I expected a worse in room response.
Of course anyone who really knows Bose knows a few truths. First, they put a lot of engineering into their products, and love them or hate them, you have to admit they squeeze a lot of sound out of small packages. I've generally found their sound to be pleasant for background listening, but unable to really get loud without sounding harsh. In addition, I've noticed that the older bandpass subs have some distortion issues, namely some "honking" problems. Sure enough, you will see those in the measurements.
Anyone remember the old saying, "No highs, no lows, it must be Bose!" Well I can tell you right now, my measurements don't really bear that out too much. They don't have extension to 20khz, but they really do extend high enough to be decent.
Now for the frequency response:
As you can see its a pretty flat response to about 6khz and then begins to roll off. It still has extension out to 13khz, but rolls off a good amount after that. The highs are certainly rolled off, but I also measured from my listening position, and was not on axis to the speaker. It may measure better on axis. The speakers are mounted above the tv which is part of the challenge. Still, a no speaker with that angle would not likely show so much roll off. however, what I find interesting is that this speaker has solid extension down to 35hz. When you consider the total volume of this speaker, that is pretty impressive extension. Sure there are any number of small high end subwoofers from Velodyne, Carver, Sunfire, etc. that could probably match or better than number by a bit, but remember: This was from around 1994 (those didn't really exist yet) and it cost around $500 total (which is about what just the subs cost when they came out). So I will just say, I'm impressed with its bass response.
Ok now lets look at the Distortion. Again, I was actually pretty impressed by the distortion. The high frequency distortion is likely a sign of clipping, nothing to pay attention to, just a measurement artifact (not amp clipping, signal clipping).
Do you see that spike at about 208hz. That's what I was calling bandpass honk. It isn't a port resonance in the obvious sense. This is an 8th order bandpass so they can sometimes have resonances that show up like this. My much larger theater bandpass subs do the same thing, just at a MUCH higher level. That measurement is calibrated against a Level 2 calibrated SPL meter (and NIOSH tests show it meets Level 1 accuracy). That means this has a spike in the distortion at just 72db's output or so. That IS audible, and with low male voices, can be distracting. Now I'll admit that this subwoofer, being so old, could have something wrong with it. I intend to take it apart one of these days to investigate, but given that there is no issue anywhere else (and that I see this with other subwoofers of similar design), I'm inclined to consider this fairly normal behavior. Otherwise, that distortion level is pretty low.
I've also included a measurement comparison against the theater. The volume levels are artificially matched, I took them at two different levels. This is basically my Gedlee speakers and subs against the Bose in a treated theater vs totally untreated living room.
Clearly the theater is better, but honestly I was impressed the Bose measured as well as it did. I expected higher distortion levels (beyond that spike) and I expected a worse in room response.
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