[norliss]

Hi there guys. I've just recently got into this whole REW thing and have just spent a few hours getting to grips with it. I would be grateful for some feedback on my results thus far.

 

[norliss]

First you have to tell us what we're looking at?

Apologies. This was the "subwoofer" setting. I did 2 512k sweeps from 0-200KHz. The different graphs relate to various gain levels and crossovers.

My main concerns were not wanting to be able to localize the bass as the sub is right next to the seating position.

Where would setting individual sound levels i.e. with test patterns on something like the Avia disc fit in with this whole process?

Thanks again.

 

[norliss]

So, this is the subwoofer without the mains, or the mains without the subwoofer, or subwoofer + mains?

It was sub + mains.

I've just been running some more sweeps so will post some more graphs if that's ok?

Thanks for your help.

 

[norliss]

Hi again guys.

The sub in question is a BK XLS300/PR (I can't post a url yet). It is well regarded this side of the atlantic and certainly not something that lacks ooph.

The sub is next to the seating position and I didn't want to be able to localise the bass, hence my using a fairly low gain level setting.

I'll post some more graphs very soon with supporting info which will hopefully be easier to make sense of!

Many thanks again for your time.

 

[norliss]

Ok here are some more graphs. For reference, the dials on the sub have 10 "marks" and these images basically span from a gain level of 3, 3.5 & 4, with crossover levels (where 0 is 40hz and 10 would be 120hz) of 3-5 and phase ranging from 3-4 (mark 0 would be 0degrees and 10 being 180degrees).

The gain level increases from top-to-bottom. Sorry I couldn't individually mark-up the graphs (although the file names are indicative). I suppose advice might be to increase the gain levels and I'll happily do this if I can avoid localizing the sub?

 

[norliss]

Perhaps not, but in your situation it isn't doing its job, and maybe a result of having the volume to low. The spec on the BK XLS300/PR is 20Hz -3dB. You aren't getting that. Your best extension is about 25Hz. It should be better. Locate the sub in a corner and see if you can't excite your room a bit more. And turn it up.....

It kind of is in a corner: well, by a recess but turn it up I will!

As long as your crossover is 80Hz or less, you won't localize the sub.

Well that will be good

BTW, the Measured tab in REW is for overlaying and comparing graphs - rather than posting multiple plots, one plot would make it easier on you.....

I couldn't find the embarrassed smilie but thanks for that I will bear that in mind!

Many thanks for your input. Another little round of REW'ing beckons

 

[norliss]

Ok I've just done another couple of sweeps (this time measuring at 70db).

This time I've left the phase and crossover the same but increased the gain to 5 (the midway point on the dial) and then 6. What sort of levels should I be looking at for the lower frequencies?

 

[norliss]

And some more with the gain turned up to 6.5. Each of these has the crossover changed slightly.

 

[norliss]

These graphs all look like they have smoothing applied. Have they?

Yes, 1/3 octave smoothing.

 

[norliss]

Well, your room is certainly cooperating, as you have no real problem modal peaks with a smooth response and crossover region, but your low end extension isn't what I would expect from that sub. It's stopping quite consistently at 25Hz rather than 20Hz ........ other than that the response is quite good.

Thanks for your feedback.

I just watched a Blu-ray disc "The Host" and it literally shook the room so much so I had to take the sub gain level down.

This is my first sub and I've never sat in anyone else's home cinema to have any kind of benchmark but that just seemed too much for me. Even at the lower gain level I could feel a serious "thud" everytime the creature's feet hit the floor!

As for the low-end thing I wonder whether it's a room thing? I must say I did notice when calibrating the soundcard that the curve tailed off considerably at the low end so perhaps I'll need to try again with a different laptop?

Also, I feel very conscious of the location of the sub i.e. right next to me: something I thought I could calibrate out. A bit disappointing really given that it really can't go anywhere else.

Thanks again for all help.