Axiom Home Page Forums General Discussion Home Theater BFD?

You might also want to check out this product, sounds like it does the same thing as the BFD.

The Velodyne SMS-1 is actually a better unit as in its software driven, has a video output so you can see whats being done, uses a mic to aid in the set up. It can be found for $500-600, and may be my next choice if I'm not happy with the set up this time around. I believe Craigsub has one so perhaps he will give us his opinion.

SS, the numbers that you show are very satisfactory from the standpoint of smoothness. At those levels 25HZ and below is below the level of audibility for those extremely low frequencies.

I have the SMS-1 with my new EP500. Although a little pricey for a sub eq, it is very impressive. I think the on-screen graphics showing real time results is worth the price of admission. I also like that I can set different curves (up to 5) that can be toggled through with the remote. I am planning on creating a movie curve and a music curve for two different seats. I am not sure what I will do with the 5th preset though. I was thinking maybe a less severe bass bump curve for movies, for when I listen at louder volume than my normal listening levels.

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for two different seats

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Hmm. That begs an interesting question: Is there a way to take multiple readings throughout a room and "average" them? As an example, my sweet spot requires that I sit dead in the middle of the loveseat. On the nights when I'm too lazy to sit upright, I'm crashed horizontally and the sound is noticably different. And of course if I'm in the chair to the left of the loveseat it's different again. So my question is, is it possible with the SMS-1 to take three different readings in three different spots and come up with a workable average for any of the listening positions? Forgive my ignorance; I'm probably asking if the sky is blue, but I really know absolutely nothing about how all of this stuff works.

No, it's a very good question. Hopefully someone knows the answer 'cause I don't

I don't think it can as of yet, but I did hear Velodyne was working on a 5 microphone setup and hub that would allow this. It is supposed to be out in the next month or two for an additional $100.

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16hz 74db
20hz 71db
25hz 67db
31.5 68 db
40hz 67
50hz 68
63hz 71
80hz 73
100hz 73
125hz 75
150 71
200 71
250 72

This is using 1/3 octave warble tones and an analog radioshack meter(adjusted measurements) positioned at the listening position at a 45 degree angle. The head unit is set in stereo mode and my Hsu sub was tuned for maximum extension.

Note: These numbers look fairly good but I noticed that when I ran the 1 hz increment test tones there was some ugly differences from one hz to the next. Some of the measurements taken with the 1/3 octave warble tones had to be estimated in the middle because the dial was traveling back and forth a significant amount on one warble tone.

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I have to wonder that while these numbers look good on paper, the human ear hears different frequencies with a different sensitivities. For example, the human ear is least sensitive to low frequencies. It is also less sensitive to high frequencies; all relative to the approximate middle frequency of 4000 Hz (supposedly where human hearing is most sensitive and, likely not coincidentally, about where most speech occurs). The human ear sensitivity response curve is something like a distorted bell curve. (Trying to remember years back to my vibrations and acoustics course).

Combine this with a room's imperfect acoustic properties and a decent sounding system can have a very strange response curve.

These sort of numbers in Mark's room may actually "sound worse" to him than his current setup.

Have people who own the BFD or the Velodyne SMS-1 found anything in the documentation that talks about "setting up an ideal response curve for your room"? I can not imagine that a flat response would sound best.