[gkinberg]

My name is Garth and I own a pair of SongTowers with dome tweeters. I have been taking room measurements with REQ wizard and I have a few issues that I have yet been able to solve. In truth, I haven't tried very hard yet and I plan to pick the brains of the folks in the acoustics circle for help soon.

However, in an effort to be thorough, I have just measured my right and left songtowers independently at close range (2 ft away) to try and reduce room effects. The measurements were taken around 83 db and I carried out 1/48 smoothing of the curves.

I am by no means trying to start a flame throwing war here. I am just looking for input from experts that can verify that my songtower response looks as it should at near field. I basically ignore most of what I see below 30 hz because it is so far past the - 3 db point. The dip observed between 100 and 200 hz is puzzling and seems to be attenuated when my coffee table is between my speakers and my microphone when I’m measuring my room.





I look forward to your comments and thanks for your help.

Garth

[DMurphy]

Just a couple of comments.   First, 2 ft is too close to get proper integration of the drivers.  The standard distance is at least 1 meter, so you need to back up at least 15 inches.  Second, the dip between 100 and 200 Hz is just floor bounce cancellation.   The woofer response in that region is hitting the floor and bouncing back out of phase.  That's a feature of any speaker that doesn't have a single woofer mounted at floor level.  I don't think the ear really picks up on it, and there's nothing to be done about it in any event.   Third, the overall response is darn good.  It's basically what I intended.  I would be interested to see what happens when you back up a bit, though.

[jtwrace]

Also change your scaling to 5dB increments on your Y axis.  Put the mic at your listening position and post that.

[gkinberg]

Hi Denis, Thank you very much for your comments. I thought I remembered that near field measurements were taken at 1 meter but my goal was to minimize room interactions as much as possible so I went even closer. Would you expect the measurement to look “better” (flatter) at three feet or “worse” than at two feet?  Watching the series right now so no measurements being taken. 

Thanks, Garth

[gkinberg]

Also change your scaling to 5dB increments on your X axis.  Put the mic at your listening position and post that.

I have taken tons of room measurements from my listening position but I intend to post them in the acoustic page in a bit. Thanks for your interest.

Garth

[DMurphy]

Hi Denis, Thank you very much for your comments. I thought I remembered that near field measurements were taken at 1 meter but my goal was to minimize room interactions as much as possible so I went even closer. Would you expect the measurement to look “better” (flatter) at three feet or “worse” than at two feet?  Watching the series right now so no measurements being taken. 
Thanks, Garth

Hi Garth    I'm not familiair with the measurement system you're using.  It's apparently not using a gated impulse signal, since measurements beyond about 4 feet aren't pssible due to loss of resolution.   I doubt that the measurements will change much at one meter.  But the overall response profile is as it should be--the midbass and lower mids should be a little above the on-axis tweeter response because of the 0W1's very broad dispersion, which can sound bright if voiced perfectly flat.

[rlee8394]

Dennis,

The software is available here:

http://www.hometheatershack.com/roomeq/index.html

It's free, so maybe you can download it and make a few measurements using this software and compare to measurements from your software. At least it could validate the software as an accurate measurement product. I think everyone would be interested in the comparison.

Ron

[DMurphy]

Thanks.   I'll check it out. 

[JohnR]

REW is really designed for ungated measurements - Room EQ Wizard. Apparently it will do gating although I've not used it that way myself.