Login / Register
 
Angles of Control Room walls
New Reply
Subscribe
#31
29th September 2008
Old 29th September 2008
  #31
Lives for gear
 
avare's Avatar
 
Joined: May 2004
Location: Hamilton, On Canada
Posts: 4,737

avare is offline
Quote:
Originally Posted by naethoven View Post
Can you give an equation or explanation of this fact that would help me understand the "Why" behind it?
You going to think duh! .9 means that 9/10s of the energy is absorbed, 1/10 is reflected. DB=10log(.1)=-10.

Andre
naethoven
Thread Starter
#32
4th October 2008
Old 4th October 2008
  #32
Gear addict
 
naethoven's Avatar
 
Joined: Jul 2007
Posts: 337

Thread Starter
naethoven is offline
Got it. Still learning, but I see what you're saying. I've been giving a lot of thought lately to soffit mounting my speakers. I see the benefits being: Create an RFZ w/out the use of absorption (on the front wall), and getting rid of speaker cabinet diffraction. I would really like to do it, but I have read somethings on GS that scare me away from it: If my speakers can/should/are designed to be soffit mounted or not? I am using Mackie HR 824s ( I looked on their website and haven't found any info on it yet.) Also, Weasel advised it was something that could be easily screwed up, and may require a pro designer.

Where can I find info to learn the DETAILS of correct soffit mounting? You wanna share any?
#33
5th October 2008
Old 5th October 2008
  #33
Gear Guru
 
Ethan Winer's Avatar
 
Joined: Oct 2002
Location: New Milford, CT, USA
Posts: 13,537

Ethan Winer is offline
Lightbulb

I don't think Mackie 824s should be soffit mounted because that puts the rear radiator inside the wall. You can call Mackie support to confirm, but I'm pretty sure they'll agree.

--Ethan
__________________
Ethan's Audio Expert book
Quote
1
#34
5th October 2008
Old 5th October 2008
  #34
Lives for gear
 
avare's Avatar
 
Joined: May 2004
Location: Hamilton, On Canada
Posts: 4,737

avare is offline
Quote:
Originally Posted by Ethan Winer View Post
I don't think Mackie 824s should be soffit mounted because that puts the rear radiator inside the wall
+1.

Verbosely,
Andre
#35
5th October 2008
Old 5th October 2008
  #35
Lives for gear
 
avare's Avatar
 
Joined: May 2004
Location: Hamilton, On Canada
Posts: 4,737

avare is offline
Quote:
Originally Posted by naethoven View Post
Also, Weasel advised it was something that could be easily screwed up, and may require a pro designer.
I don't know what Frank was referring here. It is a straightforward design principle. Like most things in acoustics, it has to be done right.

Frank:

Would you expand on what you meant?

Quote:
Where can I find info to learn the DETAILS of correct soffit mounting? You wanna share any?
The Genelec tech have as good as any details on it, with the exception of their "8 Hz isolation" recommendation in concrete walls. In summary:

Flush the front of the speakers with the wall
The wall is massive enough not vibrate and act as extended sound source(s)
Isolate the speakers so that low frequencies do not travel through the walls etc and reach the ear before sound through the air.

The above points are decreasing order of importance and greater order of cost.

Andre
naethoven
Thread Starter
#36
5th October 2008
Old 5th October 2008
  #36
Gear addict
 
naethoven's Avatar
 
Joined: Jul 2007
Posts: 337

Thread Starter
naethoven is offline
Andre,
I just went back and reviewed some earlier posts on this thread and had a question. I understand if the speakers are not flush mounted, you cannot create an RFZ in a small room like mine without the use of absorption in the first reflection points because there will automatically be reflections directed back at the mix pos. that are less than 20ms behind the direct sound. Right?

The other half of that thought is, if you DO flush mount the speakers, my theory is you can make ONLY the REAR wall absorptive and still establish an RFZ (without absorption on the front wall), even in a room as small as mine will be. (Assuming the rear wall is 100% absorptive). Correct?


I figure with flush mounting, the only reflections hitting the side walls will be from the opposite side speaker, and will be directed to the back of the room and absorbed.

Let me know if I'm wrong, this is what has me thinking I should consider flush mounting.
#37
5th October 2008
Old 5th October 2008
  #37
Lives for gear
 
avare's Avatar
 
Joined: May 2004
Location: Hamilton, On Canada
Posts: 4,737

avare is offline
Quote:
Originally Posted by naethoven View Post
Andre,
I just went back and reviewed some earlier posts on this thread and had a question. I understand if the speakers are not flush mounted, you cannot create an RFZ in a small room like mine without the use of absorption in the first reflection points because there will automatically be reflections directed back at the mix pos. that are less than 20ms behind the direct sound. Right?
Correct

Quote:
The other half of that thought is, if you DO flush mount the speakers, my theory is you can make ONLY the REAR wall absorptive and still establish an RFZ (without absorption on the front wall), even in a room as small as mine will be. (Assuming the rear wall is 100% absorptive). Correct?
No. It depends on the geometry.


Quote:
I figure with flush mounting, the only reflections hitting the side walls will be from the opposite side speaker, and will be directed to the back of the room and absorbed.
So you plan on having no ceiling?

The specifics depend on the room geometry and speaker/listener locations.

Quote:
Let me know if I'm wrong, this is what has me thinking I should consider flush mounting.
Personally I am in favour of flush mounting. But I can go either way.

Andre
naethoven
Thread Starter
#38
6th October 2008
Old 6th October 2008
  #38
Gear addict
 
naethoven's Avatar
 
Joined: Jul 2007
Posts: 337

Thread Starter
naethoven is offline
Yeah, I realized I didn't mention the ceiling in that post right after I posted it. Well, I figure the ceiling angles will be exactly a wall turned on it's side, so the same results would be produced.

Can you elaborate on what you mean by it depends on the room geometry? I know you mean the shape of the room, 3D angles, etc., but what exactly would make an RFZ without absorption impossible in a room with flush mounted speakers. (The room in my mind would of course have walls and ceiling angled to direct reflections to the absorptive rear wall.)

I appreciate you Andre.
#39
6th October 2008
Old 6th October 2008
  #39
Lives for gear
 
avare's Avatar
 
Joined: May 2004
Location: Hamilton, On Canada
Posts: 4,737

avare is offline
Quote:
Originally Posted by naethoven View Post
Can you elaborate on what you mean by it depends on the room geometry? I know you mean the shape of the room, 3D angles, etc., but what exactly would make an RFZ without absorption impossible in a room with flush mounted speakers. (The room in my mind would of course have walls and ceiling angled to direct reflections to the absorptive rear wall.)
BBC built a room like that and basically the sound was HORRIBLE outside of the listening area. Have a look at their RD reports 1995/3-5 for design details and everything about it.

Andre
naethoven
Thread Starter
#40
6th October 2008
Old 6th October 2008
  #40
Gear addict
 
naethoven's Avatar
 
Joined: Jul 2007
Posts: 337

Thread Starter
naethoven is offline
Hey, I am about to leave for work, so I haven't looked at the BBC report yet, but all things we've discussed considered, what are the benefits of flush mounting in a small room?
#41
6th October 2008
Old 6th October 2008
  #41
Lives for gear
 
avare's Avatar
 
Joined: May 2004
Location: Hamilton, On Canada
Posts: 4,737

avare is offline
Quote:
Originally Posted by naethoven View Post
what are the benefits of flush mounting in a small room?
Same as in a big room. No speaker baffle wall interference (smoother low end response), no corner diffraction (smoother high end response and more solid stereo imaging), and low end response going lower in frequency and less low end distortion for any given SPL.

Andre
Quote
1
naethoven
Thread Starter
#42
6th October 2008
Old 6th October 2008
  #42
Gear addict
 
naethoven's Avatar
 
Joined: Jul 2007
Posts: 337

Thread Starter
naethoven is offline
OK! That sounds great. But how do I handle flush mount in a small room? Would I just still have to treat 1st reflection points? But where would they be (that they would interfere with the mix pos.)? Something is not matching up in my head: If a small room like I described with a live front end, flush mount, angles directing reflections to rear wall still sounds bad, what do you do with flush mount in a small room to make it sound good? I don't see where you would need absorption. I will read that BBC report when I have a chance, I'm actually at work right now. (That's how you know the difference between a day job and working a career you are passionate about: when you are at one job but working on the other one!)
naethoven
Thread Starter
#43
20th October 2008
Old 20th October 2008
  #43
Gear addict
 
naethoven's Avatar
 
Joined: Jul 2007
Posts: 337

Thread Starter
naethoven is offline
OK, been reading a lot. I realized in MHofA that I need diffusion on the back wall of a CR like we have been talking about. I guess technically diffusion would be good on the back wall of any control room. If the distance is great enough to make the reflection off the back wall longer than 20ms, do you need absorbtion (besides bass traps) at all on the back wall if you could cover the whole thing with diffusors?

I am slowly reading through the BBC reports you cited. A little over my head, but I'm learning anyway.

Sorry I missed you in the chat room the other day Andre. I was at work.
naethoven
Thread Starter
#44
30th May 2009
Old 30th May 2009
  #44
Gear addict
 
naethoven's Avatar
 
Joined: Jul 2007
Posts: 337

Thread Starter
naethoven is offline
Reviving the control room thread!

Well, I've learned a lot since my last post, and I now have a potential design for my CR. I have attached it below. WILL YOU GUYS PICK IT APART PLEASE! There will be quite a bit more acoustic treatment in the room (RFZ, ceiling bass traps, more opportunities for diffusion). I just threw in some simple stuff I'm planning for.

The original dimensions based on 1:1.33:1.64 were 9.75'x13'x16'. I splayed the walls (>6 degrees) for a few reasons (line of sight, flutter reduction, widen the back of the room a bit so it feels bigger and more comfortable). So, I made sure the average room width was still 13'. The mix position angles are 60 degrees. Please rip it to shreads and tell me everything wrong with it (some issues may be due to the size of the existing space).

Thank you all!
Nathan Webb
Attached Thumbnails
Angles of Control Room walls-cr-top-view-1.jpg  
#45
30th May 2009
Old 30th May 2009
  #45
Gear nut
 
Joined: Nov 2007
Posts: 108

Wes Lachot is offline
Quote:
Originally Posted by naethoven View Post
The original dimensions based on 1:1.33:1.64 were 9.75'x13'x16'.
Nathan,

The 1 : 1.33 ratio is problematic. That's a 3 : 4 ratio, which makes it a perfect 4th, and perfect intervals are exactly what you don't want for room ratios (they're less than perfect, to say the least). You know how when you tune a guitar using 5th and 7th fret harmonics, you get the same tone from the two strings? (3rd harmonic of one string = 4th harmonic of the other.) It's the exact same thing here - your walls will be harmonizing in sympathy, making for a lot of reinforcement in one or two keys - in this case the keys of F and Bb - at the expense of all the other keys.

You're better off either shrinking down to a 1 : 1.26 ratio (Major 3rd) or going up to a 1 : 1.4 (Aug. 4th) Either will work okay with your length dimension. This way you'll be reinforcing the keys of either E or F#, both of which are a long way from Bb (the key of the height dimension). This is the sort of musical balance that will make your room sound even and true.

There's a bit of rounding in these numbers for the sake of simplicity.

--Wes
__________________
WES LACHOT DESIGN
Quote
1
#46
30th May 2009
Old 30th May 2009
  #46
www.circlestudios.co.uk
 
Trev@Circle's Avatar
 
Joined: May 2007
Location: UK
Posts: 3,589

Trev@Circle is online now
Excellent thread! Subscribed!
#47
31st May 2009
Old 31st May 2009
  #47
Moderator
 
jayfrigo's Avatar
 
Joined: Dec 2002
Posts: 3,520
My Recordings/Credits

jayfrigo is offline
Quote:
Originally Posted by avare View Post
BBC built a room like that and basically the sound was HORRIBLE outside of the listening area. Have a look at their RD reports 1995/3-5 for design details and everything about it.

Andre
But there are things you can take from those experiments and apply to control room shapes that don't look like coffins. They took their design goals to the extreme, trying to avoid needing any treatment at all. Think about a hybrid approach. I've designed several rooms using a mix of these principles. You can fit into existing rectangular structures easily, expand the RFZ, ease mode calculations with the rectangular outer shell, and it can work well for surround. I've referenced a few in past threads. My joke name for them is "wedgie wall," though "wedged wall" may be more appropriate for mixed company. I don't use this technique always, but it really works well as a solution under certain criteria.

Here's a link to an old post with links to a few example rooms:
Control Room Shape Design: Does symmetry trump all?
__________________
Jay Frigoletto
Mastersuite
www.promastering.com
www.studiometronome.com
naethoven
Thread Starter
#48
31st May 2009
Old 31st May 2009
  #48
Gear addict
 
naethoven's Avatar
 
Joined: Jul 2007
Posts: 337

Thread Starter
naethoven is offline
Quote:
Originally Posted by Wes Lachot View Post
Nathan,

The 1 : 1.33 ratio is problematic. That's a 3 : 4 ratio, which makes it a perfect 4th, and perfect intervals are exactly what you don't want for room ratios (they're less than perfect, to say the least). You know how when you tune a guitar using 5th and 7th fret harmonics, you get the same tone from the two strings? (3rd harmonic of one string = 4th harmonic of the other.) It's the exact same thing here - your walls will be harmonizing in sympathy, making for a lot of reinforcement in one or two keys - in this case the keys of F and Bb - at the expense of all the other keys.

You're better off either shrinking down to a 1 : 1.26 ratio (Major 3rd) or going up to a 1 : 1.4 (Aug. 4th) Either will work okay with your length dimension. This way you'll be reinforcing the keys of either E or F#, both of which are a long way from Bb (the key of the height dimension). This is the sort of musical balance that will make your room sound even and true.

There's a bit of rounding in these numbers for the sake of simplicity.

--Wes
Wes,
Thank you so much for taking time to respond to my post. I kind of see what you are saying, but could you break it down it detail for me? As far as the ratios being equal to pitch intervals, and why certain intervals are more desireable? You don't want the dimensions to harmonize with each other/ ie: have coincident modes or harmonics, right?

As for the 1:1.33:1.64 ratio, I plugged it into the bobgolds.com modecalc and I was amazed at the results. It seemed to have good distribution down to around 60Hz, it passed all the R. Walker BBC tests, the Bonello test looked great, and it was 2028cuft vol. I couldn't imagine it being much better! I see what you're saying about the coinciding harmonics, but why did they not show up on the modecalc as problems, and how could they be that big of an issue when all the tests look so good?

I really appreciate your time!
Nathan Webb
#49
31st May 2009
Old 31st May 2009
  #49
Gear nut
 
Joined: Nov 2007
Posts: 108

Wes Lachot is offline
Quote:
Originally Posted by naethoven View Post
Wes,
Thank you so much for taking time to respond to my post. I kind of see what you are saying, but could you break it down it detail for me? As far as the ratios being equal to pitch intervals, and why certain intervals are more desireable? You don't want the dimensions to harmonize with each other/ ie: have coincident modes or harmonics, right?

As for the 1:1.33:1.64 ratio, I plugged it into the bobgolds.com modecalc and I was amazed at the results. It seemed to have good distribution down to around 60Hz, it passed all the R. Walker BBC tests, the Bonello test looked great, and it was 2028cuft vol. I couldn't imagine it being much better! I see what you're saying about the coinciding harmonics, but why did they not show up on the modecalc as problems, and how could they be that big of an issue when all the tests look so good?

I really appreciate your time!
Nathan Webb
Nathan,
Well think about it - if each dimension of the room is like a drum, with a resonant frequency, and each of those dimensions is identical (ratio of 1 : 1 : 1), then the room resonates in one key only, the worst case scenario. If the ratios are closely related mathematically (e.g. ratio of 1 : 2, 2 : 3, or 3 : 4) then a similar thing happens, only a couple of "next door' keys are resonating. These are the so-called "Perfect" intervals, 1 : 2, 2 : 3, and 3 : 4 (octave, P5th, and P4th).

The other, non-perfect musical intervals are actually quite good for room ratios, and you see them listed throughout the modal literature, although I guess that disguised as numerical ratios their musical significance as intervals may often go unnoticed. For instance, the ratio 1 : 1.6 is really a minor 6th (just intonation). The ratio 1 : 1.4 is a diminished 5th. The ratio 1 : 1.26 is a Major 3rd. The ratio 1 :1.9 is a Major 7th. The ratio 1 : 2.1 is a minor 9th. And so on...

You get the picture. The well known "good" ratios are almost without exception right on, or very near, the Major, minor, augmented, and diminished intervals. And inversely, the Perfect intervals are "bad" for room ratios. The one notable exception that proves the rule is Louden's recommendation of 1 : 1.5. I can't explain that one. I don't know what Louden was thinking that day. I stand by my contention that 1 : 1.5 is bad, very very bad. The only ratios worse than the P5th are the octave and the unison.

For a more detailed description of modal resonance from a musical perspective, you can read this paper from a lecture I gave a while back:
Wes Lachot Design || Studio Design and Acoustic Consulting

I thinks it's important for folks to understand the musical implications of the various modal ratios, rather than expecting a modal calculator do the thinking and give an "answer". As to your specific question, I would point out that even though the spread may have looked good, there is a coincidence between the 3rd harmonic of the width dimension and the 4th harmonic of the height dimension. Maybe the modal calculator doesn't give negative points for this. But you ears will. Only by understanding ratios on a musical level will you be able to best interpret the modal calculator's results.

--Wes

Last edited by Wes Lachot; 31st May 2009 at 05:49 PM.. Reason: clarity
Quote
1
#50
31st May 2009
Old 31st May 2009
  #50
Lives for gear
 
Joined: Feb 2004
Location: Graham, NC

xaMdaM is offline
Nathan,

If you look on the right side of Bob's mode calc page, notice the piano layout...

It's almost impossible to create a room that doesn't have at least some sort of harmonic that's going to be that room's signature.

That's the point I was alluding to in your other ratio's thread.

When you are agonizing over the ratios for a control room, you certainly don't want to pick wavelengths that are going to become problematic when instruments are in pitch with the room.

One tip I'll pass on, (that is gonna drive ya' nuts, btw) is to make sure that you're final ratio is the FINISHED boundary size.... then work BACKWARDS to find out how big your framing should be.

Once you've done all the math to find frequencies that are not going to cause harmonic sympathy, you don't want to end up building on top of that number and accidentally just getting into a range where a note will then create a sympathetic node.

(I only hope I've been reasonably clear)
__________________
Good shit ain't cheap, and cheap shit ain't always good.

The finished studio: www.darkpinestudios.com

Studio build blog; dm mobile.com

A Rod Gervais designed studio
naethoven
Thread Starter
#51
31st May 2009
Old 31st May 2009
  #51
Gear addict
 
naethoven's Avatar
 
Joined: Jul 2007
Posts: 337

Thread Starter
naethoven is offline
Quote:
Originally Posted by xaMdaM View Post
Nathan,

One tip I'll pass on, (that is gonna drive ya' nuts, btw) is to make sure that you're final ratio is the FINISHED boundary size.... then work BACKWARDS to find out how big your framing should be.

Once you've done all the math to find frequencies that are not going to cause harmonic sympathy, you don't want to end up building on top of that number and accidentally just getting into a range where a note will then create a sympathetic node.

(I only hope I've been reasonably clear)

Yep, accounted for! Thanks for lookin out for me though!
naethoven
Thread Starter
#52
1st June 2009
Old 1st June 2009
  #52
Gear addict
 
naethoven's Avatar
 
Joined: Jul 2007
Posts: 337

Thread Starter
naethoven is offline
Quote:
Originally Posted by jayfrigo View Post
But there are things you can take from those experiments and apply to control room shapes that don't look like coffins. They took their design goals to the extreme, trying to avoid needing any treatment at all. Think about a hybrid approach. I've designed several rooms using a mix of these principles. You can fit into existing rectangular structures easily, expand the RFZ, ease mode calculations with the rectangular outer shell, and it can work well for surround. I've referenced a few in past threads. My joke name for them is "wedgie wall," though "wedged wall" may be more appropriate for mixed company. I don't use this technique always, but it really works well as a solution under certain criteria.

Here's a link to an old post with links to a few example rooms:
Control Room Shape Design: Does symmetry trump all?

Jay,
Those look really nice. Seems like I've seen those used as panel traps too. Would you mind detailing those for us?
Thanks,
Nathan Webb

P.S. Wes, I'm still studying your lecture-wonderful!
#53
1st June 2009
Old 1st June 2009
  #53
Lives for gear
 
Weasel9992's Avatar
 
Joined: Jun 2006
Location: Savannah, GA
Posts: 4,339

Send a message via AIM to Weasel9992
Weasel9992 is offline
Great posts Wes!

Frank
naethoven
Thread Starter
#54
1st June 2009
Old 1st June 2009
  #54
Gear addict
 
naethoven's Avatar
 
Joined: Jul 2007
Posts: 337

Thread Starter
naethoven is offline
Guys,
Everything else I've ever read considers the lowest axial mode to be from your Length dimension in your room. But Master Handbook of Acoustics (MHofA for those reading that may not be familiar) Ed.4 p.441 says the lowest mode is associated with the diagonal, because technically that is the longest length in the room. How do we take that into consideration when striving to balance modal spacing and everything else?
naethoven
Thread Starter
#55
1st June 2009
Old 1st June 2009
  #55
Gear addict
 
naethoven's Avatar
 
Joined: Jul 2007
Posts: 337

Thread Starter
naethoven is offline
I am using the info Wes shared and the bobgolds mode calc to test my proposed ratios. Why does the Bonello graph change when the dimensions change even though the ratio and modal distribution does not change? I read from Eric Desart something about the Bonello graph not quite being accurate, and discounting some rooms that are based on the same ratios as other rooms that the test passed. Can anyone explain this for me?

Thanks
naethoven
Thread Starter
#56
2nd June 2009
Old 2nd June 2009
  #56
Gear addict
 
naethoven's Avatar
 
Joined: Jul 2007
Posts: 337

Thread Starter
naethoven is offline
Quote:
Originally Posted by Wes Lachot View Post
Nathan,

The 1 : 1.33 ratio is problematic. That's a 3 : 4 ratio, which makes it a perfect 4th, and perfect intervals are exactly what you don't want for room ratios (they're less than perfect, to say the least). You know how when you tune a guitar using 5th and 7th fret harmonics, you get the same tone from the two strings? (3rd harmonic of one string = 4th harmonic of the other.) It's the exact same thing here - your walls will be harmonizing in sympathy, making for a lot of reinforcement in one or two keys - in this case the keys of F and Bb - at the expense of all the other keys.

You're better off either shrinking down to a 1 : 1.26 ratio (Major 3rd) or going up to a 1 : 1.4 (Aug. 4th) Either will work okay with your length dimension. This way you'll be reinforcing the keys of either E or F#, both of which are a long way from Bb (the key of the height dimension). This is the sort of musical balance that will make your room sound even and true.

There's a bit of rounding in these numbers for the sake of simplicity.

--Wes
OK Wes, after studying your lecture, I have arrived at a new ratio I think will work. 1:1.4:1.66 If I understood you correctly, these do not add up to a perfect interval. Could you please advise?

Thanks

P.S. The only thing that looks bad about this ratio, is that with 10ft as the ceiling height the Bonello graph is beautiful, but with my dimensions it has a dip in it at 80Hz. I'm thinking maybe that doesn't matter according to what I mentioned earlier. Thoughts? Explanations?

Nathan Webb
#57
2nd June 2009
Old 2nd June 2009
  #57
Moderator
 
jayfrigo's Avatar
 
Joined: Dec 2002
Posts: 3,520
My Recordings/Credits

jayfrigo is offline
Quote:
Originally Posted by naethoven View Post
Jay,
Those look really nice. Seems like I've seen those used as panel traps too. Would you mind detailing those for us?
Thanks,
Nathan Webb
Only have a second, but briefly, what's behind each wedge is not necessarily the same. You can use reflection, diffusion, hi/mid absorption, bass trapping, tuned trapping, broadband, or combination. This is part of the beauty. It's good geometry if planned right, and treatment can be whatever you need for the situation at hand.
#58
2nd June 2009
Old 2nd June 2009
  #58
Lives for gear
 
avare's Avatar
 
Joined: May 2004
Location: Hamilton, On Canada
Posts: 4,737

avare is offline
Quote:
Originally Posted by jayfrigo View Post
But there are things you can take from those experiments and apply to control room shapes that don't look like coffins.
Agreed. I was writing ion terms of what Walker did. How ofeten do we (repeat) what spalyed walls are for an d not for? As you wrote, things can be done based on critical analysis of Walker's work, but I consider discussing that in this thread a massive non-sequitor.

Andre
#59
2nd June 2009
Old 2nd June 2009
  #59
Lives for gear
 
avare's Avatar
 
Joined: May 2004
Location: Hamilton, On Canada
Posts: 4,737

avare is offline
Quote:
Originally Posted by naethoven View Post
I am using the info Wes shared and the bobgolds mode calc to test my proposed ratios. Why does the Bonello graph change when the dimensions change even though the ratio and modal distribution does not change?
Bonello analysis is based on the overall pattern. Primary criteria being a monotonicall increasikng nmuber of modes per 1/3 octave bandwith witih increasing frequency. The exception being if there is at least two modes in the previous band thath main bamd may have one less mode in it.

If you folow sound (no pun intended too much) practice, as recommended by Wes for example. The Bonello criteria will be met as well as possible.

Andre
#60
2nd June 2009
Old 2nd June 2009
  #60
Gear nut
 
Joined: Nov 2007
Posts: 108

Wes Lachot is offline
Nathan,

The ratios you mention are better (1 : 1.4 : 1.66) than what you had. You are actually is the neighborhood of a set of ratios that are among the very best, namely 1 : 1.26 : 1.59 (or 1.6). These ratios represent an augmented triad, which by definition is the most evenly spaced sequence possible for the low frequencies. I don't know if those ratios are practical for you or not, but it would be worth checking out.

There won't be any holes in the low frequencies with these ratios...

Wes
New Reply Submit Thread to Facebook Facebook  Submit Thread to Twitter Twitter  Submit Thread to LinkedIn LinkedIn  Submit Thread to Google+ Google+ 
 
Thread Tools
Search this Thread
Search this Thread:

Advanced Search
Similar Threads
Thread
Thread Starter / Forum
Replies
Matej / High end
19
jeremycox / Studio building / acoustics
36
TheBeast / So much gear, so little time!
2
GMR / So much gear, so little time!
11
Bang / So much gear, so little time!
1

Forum Jump

SEO by vBSEO ©2011, Crawlability, Inc.