# REW Graphs for my Subwoofer Placement



## hendry_2002 (Dec 30, 2014)

This is my first REW test, and I am testing it in my Living Room with 5.1 setup (no treatment at all) to at least understand the basics of REW measurements (hopefully) before my actual home theater is finished (expecting within a month), so i did couple of tests, and I want to see your opinions on my understanding of subwoofer placement vs REW Graphs

Note: only measuring my subwoofer. (channel 4)

1- First graph with my subwoofer in the front corner

2- Second graph with my subwoofer near center and left speakers and in front of my TV

3- waterfall graph (looks very bad) with my subwoofer between my left and center speakers

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1- in the first placement, there is a null near 85hz, and the rest looks normal, right?

2- in the corner placement, there is no null, however, there is an increase over 10-15db which is obvious!

3- waterfall graph looks very bad, and I need bass traps to make it better, but cannot pass WAF in the living room. but i will definitely have proper acoustic treatments in my upcoming actual HT.

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so what do you think of these graphs? and if it were you to decide, should you keep it in the corner since there is no null? and properly turn the level/volume down a bit?


note: as for waterfalls graphs, it look pretty bad, i know because there is zero treatment in our living room. 

Hopefully, i followed all your rules before posting such graphs here.

And thank you in advance.


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## hendry_2002 (Dec 30, 2014)

And yes it sounds kinda boomy in the corner, but i guess i can just turn the volume/level of my subwoofer little bit down!

what do you think?


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## Wayne A. Pflughaupt (Apr 13, 2006)

Your in-corner looks pretty good - no nulls which is always great to see. Probably a reason the sub sounds boomy is the broad peak just south of 60 Hz. 

I wouldn’t worry about the waterfall. The reason it looks so bad is that the volume level is really high - see here for some info on waterfalls and signal levels.

BTW, it takes massive amounts of bass traps to significantly reduce ringing below 80 Hz or so.

Regards,
Wayne


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## hendry_2002 (Dec 30, 2014)

Wayne A. Pflughaupt said:


> Your in-corner looks pretty good - no nulls which is always great to see. Probably a reason the sub sounds boomy is the broad peak just south of 60 Hz.
> 
> Wayne


Thank you Wayne for your great feedback.

As for the boomy sound, what do you suggest in such case? is just turning the volume/level of my subwoofer should solve this without bass traps or changing crossover?


btw, my xover is set to 110Hz, and I did not follow Audyssey calibration because it was set to 200hz!! and the subwoofer was really loud and boomy (Audyssey level was +5), so i reduced the level to +2, and changed the xover to 110hz which is to my ear sounds good so far especially when i did my favorite movies scenes testing.


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## hendry_2002 (Dec 30, 2014)

Wayne A. Pflughaupt said:


> The reason it looks so bad is that the volume level is really high - see here for some info on waterfalls and signal levels.
> 
> Regards,
> Wayne


Thanks a lot for this link, some really great stuff i found there, 

btw, i did measure my subwoofer via pink noise in REW, and the SPL reading was 60ish db before doing the actual measurement with sine waves.

which is not that high, right?


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## Wayne A. Pflughaupt (Apr 13, 2006)

hendry_2002 said:


> As for the boomy sound, what do you suggest in such case? is just turning the volume/level of my subwoofer should solve this without bass traps or changing crossover?


The most common remedy is to utilize a parametric equalizer to tame the subwoofer’s response. A house curve slope would probably help tighten up the sound as well.




hendry_2002 said:


> btw, i did measure my subwoofer via pink noise in REW, and the SPL reading was 60ish db before doing the actual measurement with sine waves.
> 
> which is not that high, right?


No, that’s not very high. Rather low, actually...

Regards,
Wayne


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## Talley (Dec 8, 2010)

I run my pink noise to 85db on the speakes and then run my tests. This way I can see where the sub is at integrated with and then I usually bump the sub up by 2db and it sounds good for me there.

mine in the corner sounded very boomy and in the center sounds best. This is mine in the center after audyssey. I haven't tried audyssey yet for the corner placement so I should do that and will try today.


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## willis7469 (Jan 31, 2014)

I ended up stuffing all 3 subs in corners due to my large space. I took a lot of time making phase adjustments to get a good response, and in my room(ymmv naturally) it worked out. This graph is with audyssey. The bottom line is the phase plot, and I'm embarrassed to say I don't know how to apply it to the SPL graph. Iow, what does it mean? Anyway, just wanted to show that corner placement can be ok.


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## Talley (Dec 8, 2010)

willis7469 said:


> I ended up stuffing all 3 subs in corners due to my large space. I took a lot of time making phase adjustments to get a good response, and in my room(ymmv naturally) it worked out. This graph is with audyssey. The bottom line is the phase plot, and I'm embarrassed to say I don't know how to apply it to the SPL graph. Iow, what does it mean? Anyway, just wanted to show that corner placement can be ok.


i have no clue about anthing beyond reading the frequency and spl readings and the waterfall decay.

impulse and phase is way over my head. wish I could attend a class on this thing.


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## hendry_2002 (Dec 30, 2014)

Talley said:


> I run my pink noise to 85db on the speakes and then run my tests. This way I can see where the sub is at integrated with and then I usually bump the sub up by 2db and it sounds good for me there.
> 
> mine in the corner sounded very boomy and in the center sounds best. This is mine in the center after audyssey. I haven't tried audyssey yet for the corner placement so I should do that and will try today.


so it's the opposite of mine, 

well, maybe i should move it to the corner again and run Audyssey to see if it can help with the boomy sound i am getting while in corner.

with REW, it makes my life much easier.


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## hendry_2002 (Dec 30, 2014)

willis7469 said:


> I ended up stuffing all 3 subs in corners due to my large space. I took a lot of time making phase adjustments to get a good response, and in my room(ymmv naturally) it worked out. This graph is with audyssey. The bottom line is the phase plot, and I'm embarrassed to say I don't know how to apply it to the SPL graph. Iow, what does it mean? Anyway, just wanted to show that corner placement can be ok.


Yeah corner sometimes works best.

i guess with my readings, i should put my sub in the corner again and run Audyssey to see how it goes.

hopefully i dont get the boomy sound 


and this is only for my living room, as i am preparing myself for the actual testings once my real HT comes to life pretty soon


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## hendry_2002 (Dec 30, 2014)

Wayne A. Pflughaupt said:


> The most common remedy is to utilize a parametric equalizer to tame the subwoofer’s response. A house curve slope would probably help tighten up the sound as well.
> 
> 
> No, that’s not very high. Rather low, actually...
> ...


Dear Wayne,

I have located my Sub in the corner again, re-run Audyssey. Then set my SPL 74-75 db on the Sub to test again with REW and here is my updated graph. (it looks good except there seems a null near 120-130Hz)

To my ears, the sub sounds great now, and very smooth and no more boomy but not sure how this null would effect my viewing experience! , so what do you think now?

*Updated: i tried my LCR speakers, and all showed similar null near 120-130hz!


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## willis7469 (Jan 31, 2014)

I'd say that looks way better. What are your speakers and sub? Also that 130hz area would probably be inaudible. It's very narrow.


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## hendry_2002 (Dec 30, 2014)

willis7469 said:


> I'd say that looks way better. What are your speakers and sub? Also that 130hz area would probably be inaudible. It's very narrow.


My living rooms speakers are Harman Kardon SAT-TS60 satellite, powered by Marantz Avr 1504.

I am pretty happy with the sound now considering this is just a living room.

and these testing are just to be prepared when my actual HT starts (in couple of weeks time), which will have Triad Gold Inwall speakers powered by Parasound Amps and the processor will be Marantz 7702.

Hopefully i will start build thread pretty soon.


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## Talley (Dec 8, 2010)

willis7469 said:


> I'd say that looks way better. What are your speakers and sub? Also that 130hz area would probably be inaudible. It's very narrow.


I agree. For a no smoothing graph this looks great. Such a narrow narrow null seems OK.

without looking at your speakers you may be crossovering below this point anyway so it's up to your speaker placement to prevent that null now.


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## asere (Dec 7, 2011)

Looks like your sub starts to roll off between 30 and 40. What sub do you have?


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## hendry_2002 (Dec 30, 2014)

asere said:


> Looks like your sub starts to roll off between 30 and 40. What sub do you have?


I am using Harman Kardon HKTS60 complete 5.1 system. 

sub is 8-Inch, 200-Watt


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## hendry_2002 (Dec 30, 2014)

Talley said:


> I agree. For a no smoothing graph this looks great. Such a narrow narrow null seems OK.
> 
> without looking at your speakers you may be crossovering below this point anyway so it's up to your speaker placement to prevent that null now.


Audyssey set the crossover to 200hz for front & 120hz for the surrounds.

i used to set it to all to 110hz, but after last night calibration with Audyssey, i did not want to change it for time being.


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## willis7469 (Jan 31, 2014)

Looks like you're good to go on LR HT. I'm curious to see a build for your real ht. Triad makes some of the only in walls that I'd use, and I think with the parasounds you'll be pleased!


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