REW and sub location

**hot grits** · **05-12-08, 05:15 PM**

I finally got REW to work after 3 days of playing with it. I dont have an EQ yet so I just plan on using REW for sub placement. I made a graph for 3 different listening positions and for 2 sub locations.

These 3 graphs are with the sub in the back corner behind the couch. The first graph is at the main listening position and the following two are off to either side.

**hot grits** · **05-12-08, 05:17 PM**

These next 3 are in the same 3 listening positions in the same order as above. These measurements are with the sub located on by a side wall.

**hot grits** · **05-12-08, 05:20 PM**

What do you guys think is the better of the 2 locations for my sub. I seem to get lower extension with the sub on the side wall, but the overall graph looks smoother when the sub is behind the couch (position 1). Any advice or opinions would be greatly appreciated. The sub is an eD A5-350 and I am a little dissapointed at my results as i was expecting to be a little flatter down to 20hz.

**Blaser** · **05-12-08, 06:52 PM**

It is hard to say but I prefer location on the side wall. If your sub has enough headroom for your taste, you might benefit from the addition of a BFD to smooth things.

**hot grits** · **05-12-08, 08:15 PM**

I am leaning towards the side wall also. I am just confused as to what the mic/meter cal line on the graph is supposed to represent. Is it just a coincidence that the graph for my sub also drops at about the same rate below 30 hz as mic/meter cal graph.

**brucek** · **05-12-08, 09:22 PM**

Quote:

I am just confused as to what the mic/meter cal line on the graph is supposed to represent

The line shows the frequency response of the mic/meter. It represents the amount of compensation that is applied to the response graph (in the opposite direction of course).
Take a look at the meter calibration file with Windows Notepad. It's a simple text file in the form of frequency and SPL level. If it shows -10dB at 20Hz, then +10dB is applied to the reading at 20Hz.

brucek

**hot grits** · **05-12-08, 09:55 PM**

Thanks for the reply. One last piece of advice needed. Ive measured my subs response in a bunch of locations. All the locations have issues. Ive settled on the sidewall next to one of my couches. The following 2 graphs are in the main listening spot. One with no EQ and one with audessey on my AVR.

Would BFD help me with the dips or do I have to solve that with sub placement and room treatments?

Would it helps with subs extension between 20 and 30 hz?

From the looks of my graph would you keep on trying different locations for the sub?

I really appreciate the help fellas.
Graph A: no Eq
Graph B: Audessey

**salvasol** · **05-12-08, 10:42 PM**

Quote:

hot grits wrote:

... Would BFD help me with the dips or do I have to solve that with sub placement and room treatments?

Would it helps with subs extension between 20 and 30 hz?

From the looks of my graph would you keep on trying different locations for the sub? ...

I'm not an expert ... I'm still considering getting a BFD too

After reading a lot of posts ... I think that the BFD can help you everywhere

... if I understand correctly, you can adjust the gain +/- to any frequency ... and accoustic panels definetely will help you with your frequency response (Do you have any panels installed???).

If you have the time and patience, keep trying the sub locations ... I wish I could do the same, but my room doesn't allow me to try a different placement of my subs

Have you played with your receiver EQ??? ... I'm sure you can manually adjust it; that's what I did with my Yamaha RX-V2700 after running YPAO

**hot grits** · **05-13-08, 08:30 AM**

I really only have 2 or 3 possible locations for the sub. I havent played with the eq on my rcvr yet. I was running a 40 ft cable to my desktop to do these measurements. I am going to move the pc closer to see if I get different results. I dont have any treatments at all. The only thing I have is a subdude under the sub. I did measurement with and without it. There was no difference. I dont think WAF will allow room treatments. Shes already not to pleased with a 130 pound sub where the end table used to be.

**Stretch** · **05-13-08, 01:33 PM**

Quote:

hot grits wrote:

Would BFD help me with the dips or do I have to solve that with sub placement and room treatments?

Would it helps with subs extension between 20 and 30 hz?

From the looks of my graph would you keep on trying different locations for the sub?

As far as I know:

-- You can boost your frequency response using the BFD, but within limits. For one thing, your sub needs to have enough headroom to handle the extra demands you're placing on it. For another, if your null is due to a room mode then no amount of boosting is going to do any good. One thing to consider is that sharp dips at some frequencies -- while they look bad on a plot -- may not be particularly noticeable during actual listening. I don't have the expertise to tell if that's likely the case with your room, sorry.

-- You can't really boost effectively below the point where your sub is rolling off. To get significantly better low-end extension, you'll need to find a placement that will give you more room gain.

-- If the low end is what's bugging you the most, then yes. Otherwise, it really doesn't look too bad to me.

Advertisement