Are my speakers in a null?

How to use REW, What is a Bass Trap, a diffuser, the speed of sound, etc.

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knightfly
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Post by knightfly »

All good points, Kris, thanks... Steve
RCA
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Post by RCA »

it realy makes sence and shows that it is not that difficult to understand.
reading the book , controlroom, studio and listeningroom design helpt also very much.

again many thanks..
I think I can work out the problem zones now :)
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knightfly
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Post by knightfly »

Glad we could help; please keep in mind, however, that this is a VERY SIMPLIFIED method that's intended to sort of "get you in the ballpark" - it doesn't even touch on the other two types of room modes; tangential modes, which occur between 4 surfaces (either two walls, floor, ceiling or four walls) and oblique modes, which occur using all 6 surfaces in a room. These greatly UN-simplify the process in some cases, to the point that once a room has been set up to rough dimensions it's sometimes easier/quicker to just run measurements/listening tests than it is to try and calculate every possible move for speakers/ears... Steve
len-morgan
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Post by len-morgan »

Which "Newell" book talks about the rear wall that seemed to work so well here? I've got "Recording Studio Design" and on page 171 I've got a discussion about walls made out of rock and stone.

len
lovecow
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Post by lovecow »

len,

Don't know if you're talking control rooms specifically. If you are, check out Figure 13.4 on pp 321, as well as Chapter 16 in Recording Studio Design. Figures 16.1 and 16.2 (pp 379-380) also illustrate the non-environment approach to control room design.

Is that what you're looking for?
---lovecow---

It is easy enough to be friendly to one's friends. But to befriend the one who regards himself as your enemy is the quintessence of true religion. - Mahatma Gandhi
len-morgan
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Post by len-morgan »

Well, I don't either! :oops: The "Newell Wall" that I was trying to find out about was referenced in the first post. It said "on page 171 of Newell's book"... I did not find anything relevant on page 171 of my book so I'm thinking it was another book by the same author.

len
lovecow
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Post by lovecow »

Oops. OK. I missed that little reference, being in "scan-mode" and all! :oops:

I checked Studio Monitoring Design and that ain't it. So it's probably Recording Spaces or Project Studios. Since I have neither here at the office, I'll have to check later and get back to you.
---lovecow---

It is easy enough to be friendly to one's friends. But to befriend the one who regards himself as your enemy is the quintessence of true religion. - Mahatma Gandhi
len-morgan
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Post by len-morgan »

I'd appreciate it. If his other books are anything like computer books (where new editions seem to come out weekly), page 171 in the referenced book probably will be in Recording Studio Design somewhere.

len
knightfly
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Post by knightfly »

Sorry, that's on page 173 of Project Studios: A More Professional Approach. There are similar sketches on P. 324 and 379 of RSD - things not totally unlike my recent sketch of a hanger bass trap here

http://www.johnlsayers.com/phpBB2/download.php?id=7353

HTH... Steve
Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...
SonicClang
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Post by SonicClang »

Someone should seriously consider making a video tutorial on figuring out listening position and speaker position. I just couldn't understand bass traps and positions until I watched the 18 minute video at realtraps.com. Suddenly everything started falling into place. I don't learn as well from reading the stuff, I'm more visual. That video was like an awakening. If I could watch a video of one of you guys figuring this out I'd learn it way better and finally understand it. At this point it's a tiny bit over my head, but I think I'm getting it. I feel like i'm in school though... grr...
Ethan Winer
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Post by Ethan Winer »

> If I could watch a video of one of you guys figuring this out I'd learn it way better and finally understand it. <

I plan to do something like this soon using my living room home theater as an example. No promises as to when though. Hopefully within a month or three.

--Ethan
razor
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Post by razor »

SonicClang wrote:Someone should seriously consider making a video tutorial on figuring out listening position and speaker position. I just couldn't understand bass traps and positions until I watched the 18 minute video at realtraps.com. Suddenly everything started falling into place. I don't learn as well from reading the stuff, I'm more visual. That video was like an awakening. If I could watch a video of one of you guys figuring this out I'd learn it way better and finally understand it. At this point it's a tiny bit over my head, but I think I'm getting it. I feel like i'm in school though... grr...
Hi this might help, just do what nightfly did except

1. import the graphs into sketchup as a texture and
2. resize on the surface you want.
3. create a rectangle in the clear areas no peak and no trough
4. use push tool to create slice
5. where the slices intersect LWH may work
6. check with your ears.

Sorry its a bit messy as I just tried this approach.

Is there a way of testing whether these nodes exist in reality and are these infact the best spots?

I guess you could take measurements at different spots and see how the mix position is effected or is this too cerebral?

Cheers
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JBL 4645
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Post by JBL 4645 »

Hello there I’ve popped on over from the Lansing Heritage site where I have started a thread to hopefully get the direct link to the (JBL room mode calculator) which I had installed on my other pc which I no longer have now.

Anyway due to some poor links to other types of software where I was unable to get the software to work first time, without having to add this and that where I would like a simple straight forwards solution to plotting the room modes out within the confines of my own room.

Now I’ve been to the Harman site and it looks things have changed around there since last year and I can’t find the link. Now if someone could please find the direct link to the software program I would be very thankful. :)
The Empire Leicester Square cinema with 56KW of JBL THX sound power!
waver
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Post by waver »

Hi,

looking closely at the picture "ModStep5.JPG" i realized that (as always recomended) being centered in the axis, for stereo imaging, the head can never be on a green spot.
What would be the down side of having a square control room used on the diagonale. Both head and speakers could be then placed on green spots.

Richard
bbgg
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Post by bbgg »

It seems I am resurrecting a thread long dead, but here it goes. :D

Peter Walker of Quad insisted that speakers should be placed along the room diagonals, on odd-denominated fractions. He said 1/3 of the diagonal was best, followed by 1/5 and lastly (barely) by 1/7 (this a no-no with bipolars, for different reasons). These spots ensure minimum standing wave excitation and they agree perfectly with the JBL Excel results posted above. See how wonderfully do 33% (=1/3), 20% (=1/5) and 14% (=1/7) fit in between the busy spots on the Excel sheet. Arguably 1/3 of a diagonal often is too much in the way in a domestic situation, and may arouse justifiable spousal ire. :oops:

Woofers should be placed along the same fractions of the height dimension, if possible. Whether this will place tweeters at ear height is another matter altogether, which only prayer may solve. :lol:

And yes, the listener should sit on the midline, ideally at 2/3, 3/5, 4/5 etc. As long as no standing wave with a midline node is excited, this is ok. Proper speaker placement ensures this.
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