Improving perceived loudness when system is constrained

D

Daniel Postilnik

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Jan 14, 2011
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San Francisco, CA
I'm working on reducing audible penetrations from a first floor business into a fifth floor neighbor's apartment in the range of 630-800 Hz. The type of material in the first floor space is fitness class instruction and club-type workout music.

While lots of work has been done to isolate the space, I've been asked to explore innovative loudspeaker isolation techniques that are non-invasive, or system processor tweaks that will increase perceived loudness without putting additional energy into the room. We use Rane processors, Lab Gruppen amps, and yoke-mounted QSC ADs-series installation loudspeakers (8-inch and dual 8-inch models).

Thanks in advance.
 
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Re: Improving perceived loudness when system is constrained

I am not suggesting this-but distortion "sounds' louder than clean.

Just sayin----------------------------
 
Re: Improving perceived loudness when system is constrained

Just to reinforce Ivan's comment humans are conditioned to associate louder with more complex spectral content. Louder vocals have more overtones (distortion), wind instruments get more complex when played louder, and car radios clip all the time.

Of course distortion alone will not make quiet loud. There are many bass helpers that generate overtones up in the higher frequency regions where we hear better so less sounds like more.

Maybe you can get them all on ear buds.

JR
 
Re: Improving perceived loudness when system is constrained

John Roberts said:
Just to reinforce Ivan's comment humans are conditioned to associate louder with more complex spectral content. Louder vocals have more overtones (distortion), wind instruments get more complex when played louder, and car radios clip all the time.

Of course distortion alone will not make quiet loud. There are many bass helpers that generate overtones up in the higher frequency regions where we hear better so less sounds like more.

Maybe you can get them all on ear buds.

JR
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John, can you give me an example of one of these bass helpers? The DBX subharmonic synthesizer supposedly reproduces content an octave BELOW the content present. That doesn't sound like what we need.
 
Re: Improving perceived loudness when system is constrained

Daniel Postilnik said:
Software solutions are not an option - this is a commercial install. The only components are a networked processor, amps, and the loudspeakers.
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There is a stand alone Maxxbass unit.

However you said your problems were in the midrange area-so this will be of not help there.
 
Re: Improving perceived loudness when system is constrained

Daniel Postilnik said:
Software solutions are not an option
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Hence the second link for the hardware. I didn't realise there was a standalone hardware unit for just the Maxxbass though so that would probably be cheaper...

Can you do anything with speaker directivity or are there adjacent tenants in all directions?

Chris
 
Re: Improving perceived loudness when system is constrained

Chris Nixon said:
Can you do anything with speaker directivity or are there adjacent tenants in all directions?

Chris
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Tenants are above, on the fifth floor, even though the studio is on the first floor. Since adding isolation to various pathways and spaces resulted in a reduction of only 2dB, we're pretty sure the sound is traveling through the structure, hence the need to isolate the floor, which is very expensive.
 
Re: Improving perceived loudness when system is constrained

Daniel Postilnik said:
Tenants are above, on the fifth floor, even though the studio is on the first floor. Since adding isolation to various pathways and spaces resulted in a reduction of only 2dB, we're pretty sure the sound is traveling through the structure, hence the need to isolate the floor, which is very expensive.
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If they're going to spend millions doing the floor, why not buy the units that are complaining? Or relocate? Sometimes the problems are too big to be worth overcoming.
 
Re: Improving perceived loudness when system is constrained

Silas Pradetto said:
If they're going to spend millions doing the floor, why not buy the units that are complaining? Or relocate? Sometimes the problems are too big to be worth overcoming.
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They have considered purchasing. It would take care of one tenant, but not another who has claimed to be hearing voices in the early morning (not in her own head, presumably).

They even asked me to consider using different sound systems, and they want me to put a plan together to put some speakers of a different type on stands in the studio, run them at full blast, and measure what happens. Am I right to say that without having the same quantity of speakers mounted in the same way, in the same positions, this would yield dramatically inaccurate results? It just seems unscientific to me.
 
Re: Improving perceived loudness when system is constrained

Daniel Postilnik said:
They have considered purchasing. It would take care of one tenant, but not another who has claimed to be hearing voices in the early morning (not in her own head, presumably).

They even asked me to consider using different sound systems, and they want me to put a plan together to put some speakers of a different type on stands in the studio, run them at full blast, and measure what happens. Am I right to say that without having the same quantity of speakers mounted in the same way, in the same positions, this would yield dramatically inaccurate results? It just seems unscientific to me.
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Playing around with different configurations to see if anything makes a dramatic difference is definitely worthwhile. It's not expensive to get some speakers on sticks and move them around a room.

You may find that the speakers are coupling to the building in one particular way, and that a different type of mounting/support fixes it.
 
Re: Improving perceived loudness when system is constrained

Daniel Postilnik said:
John, can you give me an example of one of these bass helpers? The DBX subharmonic synthesizer supposedly reproduces content an octave BELOW the content present. That doesn't sound like what we need.
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I'm tempted to answer all of them, (except ones that actually generate lower freqs, IIRC there was a guitar pedal that also generated lower frequency undertones). The vast majority use psycho-acoustic tricks where they generate higher overtones and the brain fills in the missing LF notes that the small speakers can't possibly reporduce.

But this is just a bass thing and not your solution.

If your neighbors are speaking to you, ask them record the noise that is bothering them with their IPhone or some convenient capture device. This doesn't need to be super accurate or high fidelity, it will give you a sense of what the problem sound frequency(s) are.

If it's not much of a bandpass you might get away with some selective cuts...

+==========
An exotic idea I have run up the flagpole before, and hoped a smarter (than me) speaker guy would salute, is to array some speakers so that they cancel in the far field but not in the near field.. This may be harder to do than to propose, since nobody saluted last time I mentioned it. It seems two speakers playing opposite polarity would cancel on a vector equidistant from each other, while cancellation would be incomplete elsewhere... or not... caution this is purely hypothetical and will depend hugely on speaker radiation patterns. So once again frequency range matters.

First step is to ID specific frequency range and whatever data you can about the sounds causing the complaints.

JR
 
Re: Improving perceived loudness when system is constrained

Daniel Postilnik said:
Tenants are above, on the fifth floor, even though the studio is on the first floor. Since adding isolation to various pathways and spaces resulted in a reduction of only 2dB, we're pretty sure the sound is traveling through the structure, hence the need to isolate the floor, which is very expensive.
Click to expand...

The frequency range in question isn't normally in the range of structure-borne vibrations, especially not over 4 floors vertically (what's on the intervening floors?). Are you certain that there are no air paths between the spaces (e.g. shared HVAC, elevator shafts, etc.)? And if it really is structure-borne, there's a reasonable chance it is realtively narrow-band in nature and may be possible to notch out.

Deadening the studios can help with noise transmission, as a barrier alone is less effective than a barrier plus absorption. It would also likely help with sound in the room.
 
Re: Improving perceived loudness when system is constrained

Rob Timmerman said:
The frequency range in question isn't normally in the range of structure-borne vibrations, especially not over 4 floors vertically (what's on the intervening floors?). Are you certain that there are no air paths between the spaces (e.g. shared HVAC, elevator shafts, etc.)? And if it really is structure-borne, there's a reasonable chance it is realtively narrow-band in nature and may be possible to notch out.

Deadening the studios can help with noise transmission, as a barrier alone is less effective than a barrier plus absorption. It would also likely help with sound in the room.
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+1, while structureborne noise can be transmitted great distances unless there is sufficient structural damping or a structural break, I would typically expect 630-800Hz to be less likely to be transmitted via the structure and also relatively easy to isolate at the source.

Your consultant probably already addressed this but have you confirmed that the noise is directly related to the sound system operation? Many noise control projects I've worked on were actually using noise complaints to try to address other issues. More than once I've encountered people apparently having trouble selling their property start complaining about noise from adjacent properties only to then suggest the other party purchase their property. I've also seen attempts at financial gain, differences in religious or political views or just plain not liking something or someone manifest as purported noise issues.

Your consultant probably already addressed these issues as well but is there something that ties you into not adding to the existing ambient level or are the fifth floor tenants only entitled to some accepted standard for ambient noise level? Is the ambient noise level being considered at 2 AM with the windows closed and no A/C running or during the day with A/C and all the other miscellaneous building and other ambient noises? And critical to assessing what may be practical, what is the ambient level in the receiving location and how much reduction are you looking to achieve? Keep in mind that you may need to be at least 10-12dB below the ambient level to not potentially add to the levels.

Along the same lines, how much improvement have the treatments already applied made? Were any especially beneficial? Have they gotten you close to an acceptable result or left you about where you started?
 
Re: Improving perceived loudness when system is constrained

Brad Weber said:
+1, while structureborne noise can be transmitted great distances unless there is sufficient structural damping or a structural break, I would typically expect 630-800Hz to be less likely to be transmitted via the structure and also relatively easy to isolate at the source.

Your consultant probably already addressed this but have you confirmed that the noise is directly related to the sound system operation? Many noise control projects I've worked on were actually using noise complaints to try to address other issues. More than once I've encountered people apparently having trouble selling their property start complaining about noise from adjacent properties only to then suggest the other party purchase their property. I've also seen attempts at financial gain, differences in religious or political views or just plain not liking something or someone manifest as purported noise issues.

Your consultant probably already addressed these issues as well but is there something that ties you into not adding to the existing ambient level or are the fifth floor tenants only entitled to some accepted standard for ambient noise level? Is the ambient noise level being considered at 2 AM with the windows closed and no A/C running or during the day with A/C and all the other miscellaneous building and other ambient noises? And critical to assessing what may be practical, what is the ambient level in the receiving location and how much reduction are you looking to achieve? Keep in mind that you may need to be at least 10-12dB below the ambient level to not potentially add to the levels.

Along the same lines, how much improvement have the treatments already applied made? Were any especially beneficial? Have they gotten you close to an acceptable result or left you about where you started?
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And often with "noise complaints", it is not always the actual level (SPL). But often just the fact that the person complaining can even HEAR any noise-even if the actual level is a good bit lower than ambient.

Often with nightclubs-it could be that the complainer does not like the music they play or the "type" of people that go there-so they make a complaint if they can hear it at all-nevermind the fact that you may or may not be able to easily "measure" it. Depending on the tool you use-the noise may not even show up in a simple SPL measurement.

So often there is a lot more to noise complaints than just noise or SPL.

So as with everything else in troubleshooting-FIRST you have to ACCURATELY define the problem-THEN look for solutions to THAT problem. General solutions-without a defined problem/goal in mind are usually a waste of time.
 
Re: Improving perceived loudness when system is constrained

In Australia (and I assume other countries too) when a dance party is held in a venue that's a little too close to residents, sometimes a white noise system is setup to raise the ambient noise level at the complainer's location.

Might be a possibility?
 
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Re: Improving perceived loudness when system is constrained

Steve Anderson said:
In Australia (and I assume other countries too) when a dance party is held in a venue that's a little too close to residents, sometimes a white noise system is setup to raise the ambient noise level at the complainer's location.

Might be a possibility?
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That may be a possibility but it all depends on the goals and what determines and acceptable result.

After many experiences involving noise in adjacent spaces I have found that rarely is there anything in leases or other related documents actually defining the noise levels to be provided or maintained. And if you start to apply 'nuisance and annoyance' style acceptance then you potentially get into all sorts of other factors and may have a moving target. So in many cases, unless you can identify some objective acceptable result then you not only have no basis for any analysis but may you also have no way of documenting when a realistic acceptable result is achieved.

If there currently is no established goal then providing some reference standards that might be applied for that purpose is one area where a subject matter expert may be able to help.
 
Re: Improving perceived loudness when system is constrained

Brad Weber said:
+1, while structureborne noise can be transmitted great distances unless there is sufficient structural damping or a structural break, I would typically expect 630-800Hz to be less likely to be transmitted via the structure and also relatively easy to isolate at the source.

Your consultant probably already addressed this but have you confirmed that the noise is directly related to the sound system operation? Many noise control projects I've worked on were actually using noise complaints to try to address other issues. More than once I've encountered people apparently having trouble selling their property start complaining about noise from adjacent properties only to then suggest the other party purchase their property. I've also seen attempts at financial gain, differences in religious or political views or just plain not liking something or someone manifest as purported noise issues.

Your consultant probably already addressed these issues as well but is there something that ties you into not adding to the existing ambient level or are the fifth floor tenants only entitled to some accepted standard for ambient noise level? Is the ambient noise level being considered at 2 AM with the windows closed and no A/C running or during the day with A/C and all the other miscellaneous building and other ambient noises? And critical to assessing what may be practical, what is the ambient level in the receiving location and how much reduction are you looking to achieve? Keep in mind that you may need to be at least 10-12dB below the ambient level to not potentially add to the levels.

Along the same lines, how much improvement have the treatments already applied made? Were any especially beneficial? Have they gotten you close to an acceptable result or left you about where you started?
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Brad,

I described some of the steps we have already taken. None of them were especially beneficial. Our last round gave us a decrease of 2db, but it's still 2db above ambient. It's worth mentioning that the noise level is far below what NYC state code requires, and the noise is in fact really hard to hear in the unit. It's also worth mentioning that the tenant did not complain until he was asked if he could hear anything (the person who asked that question hopefully doesn't work for us anymore, because that was really dumb).

I do think you bring up an interesting point about non-acoustical reasons for acoustical complaints. We don't know enough about the tenants to know for sure, but it's something that may be worth thinking about. People living in properties as expensive as these may be prone to hatching all kinds of schemes.
 
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