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Lack of bass in NHT 3.3.

I recently failed to sell my pair of NHT 3.3's to a local(Dallas/Ft. Worth) buyer who remembered selling them circa 2000 and feel mine are not putting out enough bass volume. As you may know they are noted for the bass from the 12" side firing woofers. I followed a suggestion and removed the jumpers and connected just the subwoofer input and was able to verify signal. Since these are perhaps subwoors rather than traditional drivers I am not certain how loud they are supposed to play. My two part question is are there any 3.3 owners in the area willing to let me visit to hear your speakers and has any 3.3 owners run into a similar issue. Many thanks, LS
trytone
trytone OP
113 posts
 
Thanks onwhy. Have the omnimic and can measure SPL with that. To my ears they seem to perform like my other subwoofer, the lowest frequencies are audible but do not have a lot of SPL. And what should the proper spl be for a sub woofer? The other drivers are certainly playing with robust volume. Not sure i have a cd with bass sweep, although it may be on the omnimic test cd but still not sure what the proper spl should be. Thanks, LS
onhwy61's avatar
onhwy61
5,242 posts
 
Set your volume so that a 1kHz tone reads at 75dB.  Then measure the readings for midrange thru bass tones without changing the volume control.  There will be peaks and valleys, but the bass level should be strong down to at least 30Hz.
trytone OP
113 posts
 
Thanks again onwhy. The omnimic shows a nice flat frequency response down to 20 Hz. My question is more about the spl levels I should expect from this 12 inch sealed subwoofer, as I have stated it seems to be about the same as my Martin Logan Grotto subwoofer, nice low frequencies but not a lot of SPL.
trytone OP
113 posts
 
Onwhy, sorry if I did not read your instructions carefully. When you say strong down to 30 Hz I am guessing that this frequency area should have the same db reading. Will check it out if I can find an appropriate cd with the requisite tones. Thanks, LS
trytone OP
113 posts
 
Onwhy I have run the test to the best of my ability and with the following info. Found an old mmg test cd(ultimate test cd). It starts with a 0 db test tone at 1khz and then offers tones at -10db of 20,30,40,50,60,100,..... Hz. The room the speakers are in, which does not offer optimal placement, though when they were auditioned at the buyers home they did have optimal placement, currently has a non weighted ambient noise level of  about 70 db. Ran the test tone at about 100 db and then ran the first few low tones. The Spl levels were pretty negligible till it got to 50 Hz. If the tests were done properly and if this result is not what the speakers were designed to produce, discounting the room and gear they are currently hooked up to, since there is no evidence of damage externally to the cones and since I have been told that crossovers should not be a problem, since both would have to fail and that the signal flows thru chokes which are not likely to fail. What other possibilities are there. I am guessing if they were both damaged i would hear some distortion and not merely a lack of volume. Sure hope there is an Agon member that currently has a pair that can weigh in. Thanks for your input, LS
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