Surrounds, which speaker?

[loonytunes]

Somehow, I knew that. Wishful thinking I guess.

I wanted to share some REW sweeps of my current setup. I was quite surprised by the measurements. Given what I am hearing in this room, the response doesn't look too bad. I have the crossover set at 80hz, no EQ applied to the sub or towers. Better sub placement, some EQ or maybe a lower crossover would help smooth out the region from 45hz to 150hz.

The first image is a full spectrum sweep, each tower individually with sub. The blue line is the right channel, red left channel. For no EQ, I think it's something I can definitely work with.

L and R.jpg

This shows the distortion. I believe the peaks between 1500hz and 3500hz are what I am hearing that upsets the highs. I'm not sure how to deal with these as I don't now specifically what is causing it yet. They are on the second order harmonic.

Dist.jpg

[davef]

Somehow, I knew that. Wishful thinking I guess.

I wanted to share some REW sweeps of my current setup. I was quite surprised by the measurements. Given what I am hearing in this room, the response doesn't look too bad. I have the crossover set at 80hz, no EQ applied to the sub or towers. Better sub placement, some EQ or maybe a lower crossover would help smooth out the region from 45hz to 150hz.

The first image is a full spectrum sweep, each tower individually with sub. The blue line is the right channel, red left channel. For no EQ, I think it's something I can definitely work with.

L and R.jpg

This shows the distortion. I believe the peaks between 1500hz and 3500hz are what I am hearing that upsets the highs. I'm not sure how to deal with these as I don't now specifically what is causing it yet. They are on the second order harmonic.

Dist.jpg

Your room response looks good. You might try to improve the blend between the towers and sub as it does appear you are getting some bass cancellations. Try playing with the crossover point and subwoofer phase.

Please keep in mind that measuring distortion is actually very complex and you really can not do so with any degree of accuracy without the proper equipment.

With this graph, it looks like your fundamental would be at around 90dB, which would put those peaks at -50dB. That is likely well below the actual noise floor of the equipment you are using. Even with that, -50dB distortion translates to 0.3%, which is far below audibility, actually quite impressive if this is an accurate measurement.

In addition, first peak is at 1600Hz, next is at 2400Hz, and next is at 3200Hz. Each of these peaks is precisely 1/2 half octave apart, and at the same amplitude, which tells me it is likely being introduced into the system and not from the speaker itself.

[loonytunes]

Ok. Thanks for the insight.

I wasn't sure about the distortion graph and how it played out. New to REW. The fundamental is cut off at top of this photo. It plots at 85db. The distortion here is shown at much lower spl. I wondered if that was audible.

Any guess on what might be introducing it? Sound driver in laptop, cable, pre/pro? All of the above?

[loonytunes]

X-over at 60hz, EQ -5 at 40hz and reverse phase on sub.

REW 60hz X rev phase -5 at 40hz EQ.jpg

Now to see how it sounds with some music.

I also thought better of the question on distortion, how could you possibly answer that?
Thanks again Dave, for your insight.

[jimb]

Somehow, I knew that. Wishful thinking I guess.

I wanted to share some REW sweeps of my current setup. I was quite surprised by the measurements. Given what I am hearing in this room, the response doesn't look too bad. I have the crossover set at 80hz, no EQ applied to the sub or towers. Better sub placement, some EQ or maybe a lower crossover would help smooth out the region from 45hz to 150hz.

The first image is a full spectrum sweep, each tower individually with sub. The blue line is the right channel, red left channel. For no EQ, I think it's something I can definitely work with.

L and R.jpg

This shows the distortion. I believe the peaks between 1500hz and 3500hz are what I am hearing that upsets the highs. I'm not sure how to deal with these as I don't now specifically what is causing it yet. They are on the second order harmonic.

Dist.jpg

Good work. While it looks smooth, your scale is huge. You have a lot of 'room' for improvement from 20-200. That is a 20 dB differential as you have plotted it. The good news is you should experience much more balanced sound once you improve that!

[loonytunes]

Thanks jimb,
I only have one sub to integrate. Once I have multiples, scale of difficulty will increase.

My last post shows the improved measurement. The sound is definately more balanced however, I did EQ 40hz back up to -3 in the parametric. I prefer the sound with a touch more bass. I will undoubtedly make more adjustments.

[racrawford65]

your latest measurement looks pretty good. Looks to be around 8 db delta between 20-100 hz.

What sub are you currently running?

Are you using an external EQ device like a miniDSP? As you probably know, the miniDSP + REW can do a great job in smoothing bass/integrating with mains. Even more useful once you go with dual subs.

[loonytunes]

your latest measurement looks pretty good. Looks to be around 8 db delta between 20-100 hz.

Thanks

=What sub are you currently running?

Dayton Audio 15". Dont remember the model. It was a flat pack kit, not sure they sell it anymore. Pretty high end.

=Are you using an external EQ device like a miniDSP? As you probably know, the miniDSP + REW can do a great job in smoothing bass/integrating with mains. Even more useful once you go with dual subs.

No, I am using the parametric in my Sherborn PT-7030. I will probably go to a Mini DSP in the theatre room as the Sherborn is somewhat limited.

[davef]

Ok. Thanks for the insight.

I wasn't sure about the distortion graph and how it played out. New to REW. The fundamental is cut off at top of this photo. It plots at 85db. The distortion here is shown at much lower spl. I wondered if that was audible.

Any guess on what might be introducing it? Sound driver in laptop, cable, pre/pro? All of the above?

Still at well below 1% distortion at those peaks and completely inaudible. It could be caused by all you mentioned, or one of those components or something else entirely. Honestly, I wouldn't be the least bit concerned - it won't be worth the time to even attempt to troubleshoot it.