Axiom Home Page Forums General Discussion Home Theater How big of a subwoofer do I need?

Hey Mojo, I see why. Smart postioning of the EP600 on that mid-sidewall alongside the length of the sofa. If you have a robust amp, I would suggest a 60hz crossover to get better deep response without compromising stereo imaging on the M80s. Your FR graph doesn't load by the way.

The other significant advantages of duals include less distortion,ringing and compression at high transients. Besides going dual, I would suggest you take a long look at acoustical treatments. Bass traps would really tighten up LF sound in that big irregulaur room.

Yes, thanks Jake. I forgot that I experimented quite a bit with the position of the EP600. I moved it all over the room including horizontally behind my couch and the current placement gave me the best results. I currently have the cross-over set for 80 Hz for movies and 40 Hz for music. I will definitely be trying bass traps and other treatments.

As for the room response graph, there is something very strange occuring on the Axiom server. I no longer see the graph either but when I view the post after doing a historical search, I can see it. I would be very interested to read your comments on this.

Its not as bad as I've seen but the 25db swing between the 50hz peak and 90hz null indicates you can really improve bass in room. Your first concern should be to eliminate that peak at 50hz. If you have the capability try crossing at 70hz first and then switch phase to see which setting smooths response with the mains 10hz up and down. I'm assuming you have the sub bypassed and are crossing at the processor. Once you have that peak tamed keep raising the crossover point, up to 90hz or 100hz, if you have to and see if the null disappears. You may just have to live with the null at 90 hz but traps in the corners should help raise it.

You can see the effect of room resonance from the periodic nulls every 25hz from 90hz to 100hz. Acoustical panels at the first reflection points would help somewhat. I know you like the imaging but experimenting with distance between the speakers and between the M80s and the wall may also provide some benefit with response. If they were my speakers I would move them out somemore but let your ear be the judge. I see you are constrained where you can move the sofa by the pillar so you will have to find the best compromise. Looks like you have a few hours of fun ahead of you.

Note typo above in first sentence of 2nd paragraph. It should say "periodic nulls every 25 hz from 90hz to 190hz"

I can’t believe I’m asking this…….because it’ll just be one more thing to worry about…

But anyway, how do you guys measure your rooms to tell what you need to do?

Thanks. I'll try what you recommend in the first paragraph.

Don't even go there Mike, you'll just drive yourself crazy if things don't go right.

Well, there are two parts to that question: 1. measuring and 2. interpretation of the measurements.

Measuring is really not very hard. It only takes about 45 minutes to an hour to map out the response at your main listening position. Use the test tones that you can find at the RealTraps website to map out your room between 10 Hz and 300 Hz. For each frequency, record the SPL (C weighting, slow) using your sound meter. Then transfer the readings into Excel.

Interpretation of the measurements is another matter entirely. I am still learning about this.

The way I look at it, Mike, if its something you'll worry about or might ruin your enjoyment ignore it. If you consider it as part of the fun with this hobby you have to do it.

The most cost effective way to improve quality of sound is not to buy more gear, its to analyse and adjust for room acoustics which is what Mojo is doing. On the other hand buying that second sub and placing it on the other mid-sidewall would also help tame those deep peaks and nulls.

Ok Jake. You've convinced me. I've ordered three more EP600s .