Questions about my subs response.

[Jerm357]

I just finished measuring my subs response and I would like to know what you guys think of it. It was done with the sub calibrated with Avia to match the mains, the main volume at -25 and using the test tones by JMAC 0 dB 256 kbps MP3 from Realm of excursion and measured at the listening position. My sub is a RL-p 15 in a 8.5cf ported enclosure tuned to 17hz. Now these measurements have not been EQed but Im planing on getting a BFD soon to try to level it out but what I would like to know is how bad am I? Will this be tameable with a BFD? Does this look like a normal response for a small room (11.5' x 11' x 8') and an unEQed sub tuned to 17hz? Oh yea I used a digital radio shack spl and added the correction values of....



10Hz +20.5
12.5Hz +16.5
16Hz +11.5
20Hz +7.5
25Hz +5
31.5Hz +3
40Hz +2.5
50Hz +1.5
63Hz +1.5
80Hz +1.5
100Hz +2

Any feedback from you guys would be a big help.
Thanks, Jeremy

[warnerwh]

One thing I hope you did is mount the meter on a tripod or at least securely some how. Also if you haven't tried moving the sub around a bit, even a few inches, that is a good idea too.

Your curve is actually ok. You do need a Behringer FBD or DEQ 2496 to take care of your peaks at 45 and 75hz. Your bass will sound alot better and your midrange clarity will even improve some.

If you can buy or build bass traps that will also help. Overall your curve is actually unusually smooth(good). Those large peaks though have to make your bass sound muddy somewhat.

I just built a friend with two of the same drivers you are using in a 14.5 ported box. It's still being finished so I have no idea of measurements.

The BFD will tame your response nicely. I'd go with the DEQ 2496 if you can afford it. Also you can get the ECM 8000 mike with it for a little more. These have been selling on Audiogon for about 250 with the mike. Once you get one of these you'll never go back. The little money they cost compared to how much they help is a true bargain imo.

What do you think of your sub? I won't even be able to hear the one I built as my friend lives 200 miles from here. Hopefully within a couple of months I can get up there. I'd just like to hear a description of what you think of it, what you're driving it with and how well it performs with music. The music part is important to my friend but HT more so. That's why I opted with going with 2 drivers hoping that the low distortion in that ported beast makes the sound quality of bass notes better.

He would have probably been fine with one driver for HT purposes only but it never hurts to have too much. Also I wonder about sensitivity. I hope he has enough power with only 600 watts for the 2 drivers. Any feedback is appreciated. Thanks

[Jerm357]

I love the way it sounds. I realy think is sound great the way it is but if I can tweak it to sound even better than thats what Im going to do. I dont realy use it for music much at all so I cant realy help you there but in HT is realy shines. I am using a Behringer EP 1500 in brige mode and an art clean box but I have the gain set real low (calibrated 5dB hotter than the mains).

I just finished my REW graphs. It looks pretty close to the manual one. So how bad of shape am in. Will I be able to fix this responce with a BFD? Does it look like its my room thats sucking out my low end or my hardware some where down the line? This graph was taken with the sub 5dB hotter than the mains by Avia (I have the receiver set with the sub 5dBhot at -10 on the sub out, which is what I used if it matters.)

[chasw98]

I just finished my REW graphs. It looks pretty close to the manual one. So how bad of shape am in. Will I be able to fix this responce with a BFD? Does it look like its my room thats sucking out my low end or my hardware some where down the line? This graph was taken with the sub 5dB hotter than the mains by Avia (I have the receiver set with the sub 5dBhot at -10 on the sub out, which is what I used if it matters.)

You are not in bad shape at all. Here are my before and after graphs of the IB I just installed.

Before EQ



After EQ



You should eq your sub by itself without any other speakers on when you are getting a handle on setting the filters. When you feel you have a good curve, then turn on the mains and surrounds to see what interaction occurs with them. At that point then you can try and compensate, but remember that your eq will only affect the sub and not your mains. Be prepared to spend some time. I've been working with equalizers for a long time and I took about 6 to 8 hours to finally get a curve that I felt sounded good.

Chuck

[oxcartdriver]

Be prepared to spend some time.

So True. I've re-tuned my sub several times and each time it sounds just a bit better. There are just so many adjustments on the EQ (I use an SMS), combined with integration with the mains, and room positions the EQ process takes quite a bit of time.

I can get close relatively quickly. Then EQ'ing is like a resume, never truly done but a work in progress.

[Jerm357]

Im waiting on my BFD to get here but Ive been working on my EQ plain in the mean time. What do you think of just cutting every thing down till its about flat with my 20hz dB mark? Heres some graphs. Am I on the right track? Does this look like the right plain to go about my problem? My filters are

Freq Gain BW/60
46hz -7 12
76.6 -7 8
51.95 -8 29
31.5 -2 4

[ThomasW]

This is not something that's practical to do in the abstract. When you get the BFD start playing with filters then you'll know what works and what doesn't.

[Jerm357]

With the graph shown I have the gain at only 1/4 (9 oclock) and 0db on the subout, I feel I have a lot of headroom on the amp.
When I play a 20hz sine wave the woofer barly moves. For this reason I feel that more gain would be a good thing but, the problem is when I calabrate the levels with Avia my level (on the amp) must stay very low (below 1/4)and between -10 to -5 on the subout to get it to match up at 85db. This is probly because of these high peaks at 45hz and 75hz, Dont you think?