Subwoofer Setup

[nottaway]

I used a RS analog spl and experimented with different settings.

Looks like the spreadsheet is saying play 50Hz warble and adjust to 83db. Looks like its level matching below the crossover point with the lowest value. This looks like a problem to me since I am down ~15db at the 50Hz range. Therefore the transition will be unbalanced at the crossover point, right? Without a EQ it looks like the sub will be about 15db hotter than the mains at crossover

Here are the numbers with the HSU cd and tracks 9-21



Suggestions? I just treated the room with 4 bass traps 4" OC703 2x4ft 4 inch air gap in back and 4 acoustic panels at primary reflection points 2" OC703 2x4ft 4inch air gap in back.

I was hoping to get the response flatter, but I know my room is a nightmare.

Room= 15x15x9

[Pete_Hsu]

Hi nottaway,

I have lots of questions for you!

Are these measurements with only the subwoofer (mains off)? What crossover frequency is being used between mains and subwoofer? Does the room open to any other areas of the house, and if so, where are those openings and what are the dimensions of those rooms?

Presumably, this data is based on measuring the subwoofer when placed behind you, with SPL meter at your listening position and ear level, correct?

Finally, what readings do you get on the SPL meter when the subwoofer is placed in the other locations?

One thing you can try is inverting the phase on the subwoofer to see how that affects the measurements.

With respect to level matching, in my opinion you should just exclude the 50Hz data point when level matching subwoofer with mains.

Thanks!

Sincerely,

[nottaway]

Pete,

The measurements are with the mains on, and crossover set to 80Hz. Here is the diagram of the floorplan:


Measurements are with subwoofer behind me and spl at ear level. The other positions were pretty similar with respect to the 50Hz dip and the other irregularities. I like the current position the best, but can't tell which of the graphs are the best. They all look pretty bad.

Should I level match for seamless transition, or get average response and level match that? This thing is really working on some of the more intense sequences ~100db, so I really don't want/need louder. I am looking for the most "correct" setting.

If you had to pick one of my rotten graphs which setting would you use?

[Dr_Hsu]

Did you apply correction for the bass roll off in the SPL meter? You should add 7 dB to the actual meter reading at 20 Hz, etc.

Please show the response above 80 Hz as well. If level above 80 Hz is also down in the 60 - 70 dB range, it would imply a broad peak in the 60 - 80 Hz range. Try setting the crossover on the sub to 'in' and play with the crossover frequency to bring down the 63 and 80 Hz level to match the rest (assuming that your SPL numbers are corrected for the bass roll off of the Radio Shack meter).

[nottaway]

Originally Posted by Dr_Hsu

Did you apply correction for the bass roll off in the SPL meter? You should add 7 dB to the actual meter reading at 20 Hz, etc.

Please show the response above 80 Hz as well. If level above 80 Hz is also down in the 60 - 70 dB range, it would imply a broad peak in the 60 - 80 Hz range. Try setting the crossover on the sub to 'in' and play with the crossover frequency to bring down the 63 and 80 Hz level to match the rest (assuming that your SPL numbers are corrected for the bass roll off of the Radio Shack meter).

You are absolutely correct, I forgot to correct for the spl meter. Here is the corrected graph extending to 250Hz.

[Dr_Hsu]

Looks better. Try setting the crossover on the sub to 'in', crossover around 60 - 70 Hz, and raise the sub level about 4 dB. Use MO/OPP setting.