Am i reading this right ? - Home Theater Forum and Systems - HomeTheaterShack.com

 
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post #1 of 10 Old 01-12-16, 04:46 PM Thread Starter
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Martin
 
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Am i reading this right ?

Hi guys,

My home theater room does not have any acoustic treatment and so I'm planning to make some investment on panels. Before that, I wanted to understand where exactly I need to make improvements.
I was able to run a REW measurement on my room (first time) and I'm trying to interpret the water fall graphic.

Based on online documentation (dolby recommendation) the decay time for a home theater should be between 0.2 and 0.4 seconds. Looking at my graph I definitely need some bass traps but also I see that at mid and high levels the decay time is short, seems sound is decaying 0.18 seconds for the most part.
Does this means I need to add some diffusers ?

Also I see lots of peeks and difference in dB at different frequencies, my understanding panels will improve this.

Anything I'm missing ?

(Image attached)
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post #2 of 10 Old 01-12-16, 06:21 PM
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Re: Am i reading this right ?

Hi please read this link how to scale your graphs http://www.hometheatershack.com/foru...ing-graph.html

Waterfall graphs are only good from 0-300hz.

For decay in the higher frequencies use RT60

Better if you post the mdat file
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post #3 of 10 Old 01-12-16, 07:49 PM Thread Starter
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Re: Am i reading this right ?

Phillips, the link you sent says to set the frequencies from 0 to 25,000 Hz (not 300Hz) since this is a full measurement. I didn't just measure the subwoofers only (front speakers also).

As your per recommendation I'm attaching the whole mdat file.

Really appreciate your help.
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post #4 of 10 Old 01-13-16, 06:19 PM
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Re: Am i reading this right ?

Wont have chance to look at the mdat (at work)

Scale the below and post please
Waterfall only is good for 0 - 300hz otherwise has no place
RT60 is good from 500hz up
Frequency response from 0-20,000hz
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post #5 of 10 Old 01-13-16, 08:34 PM
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Re: Am i reading this right ?

First off... Welcome fellow Htowner. I'm a local so gotta give a shout out.

Second... It seems your subs are really juiced up down low. Try turning them down a bit. Kind of hard to really see where issues are because your midbass and midrange stuff is 20db lower than your 12hz to 70hz. It's really bloated imho.

Can you share some specs? Room size/setup and such. I have a source locally where you can pick up 2'x4' panels of 4lb minwool for cheap. Send me a PM and I'll dig up the info. Do you plan on doing your own treatments? Or purchase commercial ready stuff?

For example here is mine... I have it boosted in the 20-40 but I am going to drop that back down a couple of db... maybe 3 exact to flatten it out better but still have a few more than the midbass.
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Last edited by Talley; 01-13-16 at 08:43 PM.
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post #6 of 10 Old 01-14-16, 09:02 AM Thread Starter
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Re: Am i reading this right ?

I'm looking to buy something already made. Actually I was looking into GIK acoustics products, they have been really helpful.

This people in Houston would they also come home, install and maybe even check acoustics of the room to make sure everything is ok ? .. or they just sell the panels ?

I'm attaching the requested images plus room dimensions, details and photos. Comparing to yours, mine looks pretty bad.

I have two subwoofers one on front and the other on the back. After the 60Hz seems I have bunch of nulls ... somebody suggested they may not be in phase with the mains.

Thanks for comments and help ...
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Am i reading this right ?-rt60.jpg  

Am i reading this right ?-waterfall.jpg  

Am i reading this right ?-allspl.jpg  

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post #7 of 10 Old 01-14-16, 01:26 PM
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Re: Am i reading this right ?

Rt60 won't matter a whole lot in your space. I'm flat right around .28 from 100 to 10k. Your not too far off really.

I would throw some aborption panels in stairway space on the sidewalls ceiling and the back part.

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post #8 of 10 Old 01-15-16, 08:42 AM Thread Starter
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Martin
 
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Re: Am i reading this right ?

Yes, I'm going to do that.

I will post the measurements after those panels are installed.
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post #9 of 10 Old 09-19-16, 08:51 AM
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Re: Am i reading this right ?

Hi Talley,

would be interested to know the REW meas. parameters used for the measurement you show in post #5 ; or the set of parameters you would recomand.

Hereafter is what I measure with my system and 4 sweeps 512k length.
The smoothing is 1/12.

It seems to me that I get slightly more modulation (dips and hips) in the med/high freq range (and actually low range as well) and I was wondering if this is a result of my room or the way I measure it ?

Thanks for your support
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post #10 of 10 Old 09-24-16, 01:15 AM
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Re: Am i reading this right ?

Hi Talley,
was wondering if my query reached you ?? I'm quite a newbee in posting.
Thanks for your support
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