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Weird Bass Reponse on my Speakers.

I just got a Talon ROC 2002 subwoofer dedicated mainly for 2-channel system. I tried to setup crossover point by using Radioshack SPL meter to find out what frequency that my Sonus Faber Extremas started to dip. I got weird results using Stereophile Test CD 1 (1/3-octave warble tone at -20dB). Here they are(SF Extremas only no subwoofer).

Frequency----------------SPL Meter Reading
1KHz--------------------->70 dB(reference level)
200Hz-------------------->62 dB
160Hz-------------------->63 dB
125Hz-------------------->58 dB
100Hz-------------------->52 dB
80Hz--------------------->53 dB
63Hz--------------------->60 dB
50Hz--------------------->70 dB
40Hz--------------------->61 dB
31.5Hz------------------->55 dB
25Hz--------------------->52 dB
20Hz--------------------->below 50 (unmeasurable by RadioShack SPL meter)

From the readings above,SPL readings started to dip at 200Hz(62dB) until it reach 52dB, which has the lowest value, at 100Hz and climbing up to 70db(reference level) again at 50Hz. And then I got lower dB as the frequency went lower.

So, I set the crossover frequency of my sub at 40Hz. and the SPL reading for lower-bass after combining subwoofer are:
(Upper Frequency responses are still the same)
50Hz---------------------->70 dB
40Hz---------------------->70 dB
31.5Hz------------------->70 dB
25Hz---------------------->68 dB
20Hz---------------------->54 dB

Here are my question:
1. Is the dipping between 63-200Hz and going up at 50Hz considered normal?
2. Is there anything wrong my speakers? Could it be other tube gears or my room that make cause this problem? (My listening room has no left wall at all)
3. How's your opinion on Lower bass responses after combining the subwoofer?

I'm pretty happy with the result musically but I think mid-bass responses might still be the problems for me.
My equipments are:
CDP: BAT VK-D5SE
PRE: BAT VK-5i (w/ Amperex 6DJ8 orange globe tubes)
AMP: BAT VK-60

Thanks for looking!
ted263

Showing 1 response by sol322

sol322
426 posts
 
Ted:
You definitely have very nice equipment .
Now to the bass..
IF you have a camera tripod you can attach the SPL and set it in your chair at the same position your head is and measure / writing results easier ...... see following comments below
1-First try to measure again at higher volume. At the low levels you´re measuring outside noise might be affecting the readings and with more energy in the room your results can spread better and be closer to the actual SP you get under listening conditions. Go to let´s say 85 for the 1 kHz and repeat your measurements with and without sub as you did before.
2- Repeat the same FOR EACH SPEAKER (disconnect the other one taking all precautions to avoid damages!!!!!!! like short circuits) and with no sub. This will provide you with information on the different response you get at each speaker position in other words you´ll know your enemy better). As you pointed out the room is not symetrical so don´t expect to get even bass response specially not having a wall in one side, hey I also live in the less than perfect real world room most of us do..
3- As Chilidog says each room / setup is different. Mine is a rebel I´ve been trying to tame.....
Move your listening position i.e. measuring point one two feet forward and backwards and you´ll notice changes in the bass response, hopefully you might find a better place for your chair/speakers combo that will be more satisfying.
Don´t dispear have patience be methodic on your approach keep a log and have fun!!!
Luis
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