# REW - Mains + Sub First Results



## neo_2009 (Nov 13, 2009)

I would like to ask your help in order to understand my first measures using REW.
My first experience was measuring the mains + sub.
Below are the SPL and the Waterfall graphs.


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## neo_2009 (Nov 13, 2009)

Today i've remove the mains out of the equation, in order to analyse the subwoofer only.

In attach, i insert two more graphs, namely :

- SPL for the sub only
- Overlapped SPLS curves for the Mains (L+R) and the isolated SUB.
- Waterfall for the sub only

I've also inserted a picture of my room, showing the speakers positions.
The room is an attic, and its visible in the right corner, the inverted V shape of the roof, made of a plasterboard material.

The Speakers are XTZ 99.26, sub a BK XLS200, and the AV has a 80Hz crossover.

When watching a movie, with very low frequency sounds as helicopters, car engines, sometimes the roof vibrates a lot.
Looking to the charts, it seems that the frequencies the 44.5 peak is responsible for it.

Would it be possible to help analyse this graphs with more detail?
Thanks in advance 

Now the pictures :


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## AudiocRaver (Jun 6, 2012)

Looks like some long decay times, probably a fairly live room in general. Some LF absorptive materials & treatment might be in order, maybe a bass trap or two. Looks like your measurements are basically sound. Can you post your .mdat file?


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## neo_2009 (Nov 13, 2009)

Thank you very much for your time to analyse my data 

Please download the mdat file from here: https://cloudpt.pt/link/df23b3d9-d1d7-48a1-96a3-0761b42699f5/Full_Study.mdat

And attached is the room schematic


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## tonyvdb (Sep 5, 2007)

Have you tried placing the sub in different parts of the room IE a corner or along the side wall? 
I do agree, just by looking at the picture you have a very bright room, reflection would be an issue for sure.


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## neo_2009 (Nov 13, 2009)

tonyvdb said:


> Have you tried placing the sub in different parts of the room IE a corner or along the side wall?


Yes, initially the sub was placed in the left corner and i think the vibrations were greater in that position.


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## tonyvdb (Sep 5, 2007)

I think that room is a good candidate for some bass traps.


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## Phillips (Aug 12, 2011)

neo_2009 said:


> The Speakers are XTZ 99.26


Matter of interest what do you think of these speakers fro *music *pluses and minuses?


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## neo_2009 (Nov 13, 2009)

Phillips said:


> Matter of interest what do you think of these speakers fro *music *pluses and minuses?


They are very detailed, with a very open midrange and a wide presentation. The sound is very spacious and full and i particularly like their presentation of female voices like Eva Cassidy or Katie Melua. 
There is a slight sibilance on the "sss" sometimes, but i think its due to this being the MKI versions. They are partened with an Arcam AVR 350 (and a BK XLS200), which i think its a wonderful combination.

For some time i add them a MF M1DAC using stereo direct and bypassing the Arcam's digital controls, connected the XLS200 by high level, and it was a fantastic combination for music.

I've previously had a Monitor Audio RS1, but sonically, the XTZ are far better speakers, they are at least at the Monitor Audio GS level. Obviously, to be able to provide this performance at its price level, there had to be some cuts, and its visible comparing the finishing materials on MA vs XTZ. The MA are a more polished product, the XTZ (at least the 99.26 normal black) aren't as refined. 

For movies, i use them with the jumpers in the +3db position that elevates the treble by 3db, which adds some dynamic that is very well suited for movies.

All in all, i think they are an amazing value for money option.


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## fitzwaddle (Aug 25, 2010)

neo_2009 said:


> For movies, i use them with the jumpers in the +3db position that elevates the treble by 3db, which adds some dynamic that is very well suited for movies.


Ouch, I could never do that - I use a house curve to roll off the top end, otherwise it exascerbates my lovely case of tinnitus.


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## Phillips (Aug 12, 2011)

neo_2009 said:


> They are very detailed, with a very open midrange and a wide presentation. The sound is very spacious and full and i particularly like their presentation of female voices like Eva Cassidy or Katie Melua.
> There is a slight sibilance on the "sss" sometimes, but i think its due to this being the MKI versions. They are partened with an Arcam AVR 350 (and a BK XLS200), which i think its a wonderful combination.
> 
> For some time i add them a MF M1DAC using stereo direct and bypassing the Arcam's digital controls, connected the XLS200 by high level, and it was a fantastic combination for music.
> ...



Thanks for that they sound great for music.


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## neo_2009 (Nov 13, 2009)

AudiocRaver said:


> ... Some LF absorptive materials & treatment might be in order, maybe a bass trap or two ...


Regarding Bass Traps, are you refering to this ones : http://www.amazon.co.uk/AFBT02-Acou...UTF8&qid=1367930739&sr=8-2&keywords=bass+trap

Regarding the LF absorptive materials & treatment, something like this ?
http://www.amazon.co.uk/GIK-Acousti...id=1367930797&sr=1-9&keywords=acoustic+panels


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## AudiocRaver (Jun 6, 2012)

You are on the right track, but recommending specific materials/structures/products is not my strongest area. I think it is time for you to start a thread in our Home Audio Acoustics forum, where you will find some of the best expert help available.


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## neo_2009 (Nov 13, 2009)

Ok, thanks.

In this weekend i will take measures of the mains only, and will try new sub positions, both on the left and the right corner. 
I want to gather all the information i can, to have a clear picture of the room and its iteration with the speakers.

In that regard, do you have any hits of specific measures that could be taken to provide a better understanding of the room/speakers?

After taking those measures, i will them try to understand the main problems, and will look for your help in order to correct them.

Thanks again for your help.


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## AudiocRaver (Jun 6, 2012)

neo_2009 said:


> In that regard, do you have any hits of specific measures that could be taken to provide a better understanding of the room/speakers?


L main
R main
sub (different positions)
L main + sub (different sub positions)
R main + sub (different sub positions)

NOT L + R mains together (useless with swept measurements)


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## Dwight Angus (Dec 17, 2007)

Yeah I measured L + subs plus R+ subs and got reasonable measurements. I tried sweeps with both mains playing together and could not get measurements that made sense. The above 10Kz to 20kz sweep I got 15 db drop. This must have to do with Umik limitations regarding stereo responses.


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## Phillips (Aug 12, 2011)

> Yeah I measured L + subs plus R+ subs and got reasonable measurements. I tried sweeps with both mains playing together and could not get measurements that made sense.


Would you like to post these mdat measurements left & right + combined.




> The above 10Kz to 20kz sweep I got 15 db drop. This must have to do with Umik limitations regarding stereo responses.


I would doubt that, more likely to be time alignment, nothing to worry about your ear (one only) isn't in the middle of your head which is where we place the mic.


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## Dwight Angus (Dec 17, 2007)

Phillips said:


> Would you like to post these mdat measurements left & right + combined.
> 
> 
> 
> ...


I will post early in new year. Cheers


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## eddysoen2020 (Apr 16, 2012)

According to me, you would not be able to get good bass with this room layout. To be able to get good bass yout room layout should be symetrical then place the sub in the center front. Bass starting from 20Hz has a wavelength of 17.2m long, once it come out of your sub woofer, it will hit the wall at the right hand side while the other side is empty. This asymetrical layout will cause the bass to sounds awful. Placing a basstrap on the right wall will not fully solve the problem. I have set a lot of sound system in various room layout, the only room that I manage to get the bass right is in a symetrical room.


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