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Post by vaughan on Mar 3, 2013 8:05:24 GMT -7
Hello, I was having an argument with a buddy yesterday where he said that an in-wall speaker is an infinite baffle. Take a look here :  The speakers look ported to me. Can this work as an infinite baffle? I thought infinite baffle was large sealed were the drivers are operating in free air. |
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Post by maxserg on Mar 3, 2013 9:49:45 GMT -7
Theese are studio monitors "soffit mounted" They are bass-reflex boxes, very different from IB. This is flush mounted from the angled wall towards the sound engineer. It augments the bass by not needing baffle step compensation cicuit.
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Post by vaughan on Mar 3, 2013 9:58:24 GMT -7
Would I be correct in saying that an infinite baffle must be sealed? You can't have a ported IB?
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Post by FOH on Mar 3, 2013 10:08:22 GMT -7
By definition, an IB subwoofer system, is a sub-set of the sealed alignment.
I've seen two attempts at adding a tuned port to an IB. However, by definition, that becomes a Large Low Tuned, LLT, ... or Very Large Low Tuned, VLLT.
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Post by vaughan on Mar 3, 2013 10:10:25 GMT -7
So you are saying that if those studio monitors were sealed and soffit mounted it would be an infinite baffle?
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Post by FOH on Mar 3, 2013 10:45:13 GMT -7
Theese are studio monitors "soffit mounted" They are bass-reflex boxes, very different from IB. This is flush mounted from the angled wall towards the sound engineer. It augments the bass by not needing baffle step compensation cicuit. Additionally, flush mounting possesses many other theoretical benefits too. The biggest advantages arise from minimizing negative diffraction, and entirely eliminating SBIR, ... which is the acoustic distortions from the energy encountering the front wall and coming back out of phase. Also, there's an inherent increase in the manner inwhich the energy is transferred to the room,...due to the half space implementation. Flush mounting into the eliminates the time smearing effects associated with speaker cabinet's edges, and immediate surroundings causing diffraction. Thus increased imaging and clarity from better transient response, etc. The SBIR interference between the direct energy, and the energy reflected off the wall(s) behind and adjacent to the speakers. The problem occurs when the reflected energy interacts destructively with the direct sound. Oftentimes this can easily null a significant amount of output right in the middle of the important bass range, perhaps the two octaves between 60hz and 180hz. But it all depends on the spacing. So you are saying that if those studio monitors were sealed and soffit mounted it would be an infinite baffle? No. They would only be an IB if the baffle separating the front output, with the back output was essentially infinitely large. This link, is the first FAQ; home.comcast.net/~infinitelybaffled/index.htmlExcerpted; "Think of the baffle as an infinitely large boundary that provides isolation/separation between the front-wave and the rear-wave coming off the driver/drivers. For practical purposes this means the drivers are mounted so they share a common boundary between the listening room and an adjacent space. This adjacent space can be the attic, basement, crawl space, garage, or any room that shares a common wall with the listening area.
However the IB is created, there must be adequate isolation between the front wave and rear waves. Complete isolation isn't mandatory. This means that small cracks and openings, louvered doors, etc., aren't a significant problem." |
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Post by FOH on Mar 3, 2013 10:49:57 GMT -7
To elaborate more, the monitors in the picture are Dynaudio, and they're vented designs. However, even if they were sealed, then they'd be soffited, flush mounted, sealed alignment.
An IB is an acoustically large backspace.
This is determined by the TS parameters of the driver.
Again, from the FAQ;
"The rule of thumb is that for each driver used, there should be a space no smaller 10 times larger than the Vas of the individual driver. That is then multiplied times the number of drivers. 10 times the total Vas or larger is considered optimal. For a more in depth explanation regarding the 'why' of the of the 10 times Vas recommendation click HERE
I want to add a bit of an addendum to the answer to question #6. For those that can't do a 10 times Vas IB, but can do at least 4 times Vas, go ahead and build it. Now this won't be a true IB (Qts =Qtc) . But anytime you can get a space that's 4 times Vas, you'll have a sub with better sound quality than a standard portable box sub. Note, one will need to use standard sealed box construction techniques with a 4 times Vas box. Be sure to choose low Vas drivers if you take this approach."
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Post by vaughan on Mar 3, 2013 11:05:50 GMT -7
But isn't the back space in that pic (behind the soffit mounted speakers) large enough to support infinite baffle?
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Post by FOH on Mar 3, 2013 11:35:46 GMT -7
But isn't the back space in that pic (behind the soffit mounted speakers) large enough to support infinite baffle?  The monitors are mounted in a wall that separates the control room with the tracking room, .. where the piano is. Those monitors, are no different than any other speaker .... except there flush mounted in the wall. They appear like they're the M3A, or the newer M3X stuff. They're simply a speaker, like any other box type speaker with four sides, and a top and bottom. As I stated above, they're vented design for the woofer section. I'm sure the mids and highs are sealed. Here's those, or the newer model,...it's a double 12" vented. dynaudioprofessional.com/m-series/monitors/m3xe/ Your questions are puzzling. But I hope I'm helping.... I've got a feeling no. |
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Post by vaughan on Mar 3, 2013 11:38:34 GMT -7
Apologies for being an idiot. So because the front wave is not separated from the rear wave, it can't be an IB? By installing it in the wall that can't happen, hence no IB operation? Being ported design also excludes it from being an IB. Correct me if I'm wrong here. Sorry again to pester ... I am a very slow learner.  |
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Post by FOH on Mar 3, 2013 11:57:23 GMT -7
Apologies for being an idiot. ..... Correct me if I'm wrong here. Sorry again to pester ... I am a very slow learner. No problem. So because the front wave is not separated from the rear wave, it can't be an IB? Correct By installing it in the wall that can't happen, hence no IB operation? No, it's not the wall, it's the speaker cabinet. This particular speaker is a vented/ported design. The tuned port reinforces the main front output at the frequency designed desired. Most every loudspeaker is either sealed, or vented. There's other types, but we'll keep it mainstream for now. Being ported design also excludes it from being an IB. Correct .... the backwave energy re-combines with the front wave via the tuned port. |
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Post by vaughan on Mar 3, 2013 12:20:29 GMT -7
FOH, thank you very much for taking the time to explain things. I understand things much better now.
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Post by FOH on Mar 3, 2013 13:32:38 GMT -7
No prob
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