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Help decipher Sub Crawl readings Please

post #1 of 2
Thread Starter 
I'm trying to find the best spots for my two HSU VTF-3 MK4's. I would really like some imput on where you guys think I should put them (see chart below). I currently have position 1 & 5. Bass sounds good in MLP but not so good anywhere else. Which is fine but if I listen to music while walking around room or sitting at computer the bass just isn't there.

I did the sub crawl just as Dr HSU outlined (below) in one of the threads on HSU Forum. The only thing I changed was I set the master valume to 75 dB (playing the 50 Hz tone) instead of the 70 dB he instructed.

Below are my results. The old Radio Shack analog meter was bouncing around quite a bit, so I tried to be consistent picking the number it landed on most or an average. I used average if say it bounced between 72 and 74 without really holding on one number then I chose 73.I did add the correction values listed in the instructions.

20Hz 25Hz 31.5Hz 40Hz 50Hz 63Hz 80Hz

1) 67 64 69 73 75 68 67

2) 74 74 68 68 71 69 67

3) 76 76 72 71 66 64 64

4) 79 80 78 76 74 65 62

5) 80 79 79 79 79 70 66

6) 79 77 76 74 75 64 61

7) 78 74 71 66 72 71 65 (last resort doesn't really fit well)

8) 78 71 70 71 77 74 67 (last resort doesn't really fit well)

With my very limited knowledge I am assuming I have major room problems for the 60 - 80Hz range. Like I said I been using 1 & 5. Position one is where my first sub has been since I purchased back in Febuary. I like that it rumbles the couch and doubles as a end table.

Proceed as follows:

Place the sub at your listening position, woofer at ear level. Set it to two ports open, EQ2, Q=0.7.

Put the SPL meter at the current sub location, at the position where the woofer would be if placed there.

Play the 50 Hz tone on the CD we gave you. Adjust the master volume on your receiver to get 70 dB reading on your SPL meter (set to C weighting, slow).

Now play from 20 Hz up to 80 Hz (track 10 - 16). Write down the measured SPL at each frequency. Add 7 dB to the 20 Hz reading, 4 dB to 25 Hz, and 2 dB at 31.5 Hz. This would correct for the meter's response.

Move the SPL meter to the alternative locations. Repeat the measurements for each location. Do not change the volume of the receiver for the subsequent tests. I want the results when the subwoofer is fed the same test signal. Remember to make the same corrections to the measured SPL in the 20 - 31.5 Hz range for all positions.

Edited by Soupy1970 - 10/14/13 at 10:11pm
post #2 of 2
Thread Starter 
Here is a really bad sketch of my room. The scale isn't quite right as for as the Utility room goes. It does almost take up a quarter of the room but not quite. Position 1 is the sub next to couch and behind chair. Position 5 is the right corner. Position 2,3 &4 are far right wall starting across from position 1 working toward the corner position 5. 6,7 & 8 are the screen wall starting from corner position 5. 7 & 8 are right and left of Center speaker and really do not fit well at all. Dizzy yet? Here is the Sketch.

I'm eventually going to refinish the long wall and move the layout so that will be the front wall. That should open things up and help with better placement options. It is a crude paneling wall now that was framed with 1x2 I think. So I need to rip that out and start from scratch, plus there is a window I need to cover. The wall I am using now for my screen is a wall I built a while back (used to be paneling) before I ever decided to put a theater down stairs. This project is probably 6 months away though.
Edited by Soupy1970 - 10/14/13 at 9:19pm
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