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Volume through walls of speakers with rear bass drivers

garbz

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I have a shower thought that I wanted to run by someone who understands this better than I do.

Most speakers especially in the bass (sub 150Hz) region have spherical radiation pattern. So on theory the volume for these lower frequencies is the same standing in front of the woofer as behind (opposite side of the speaker). This would then equally apply to speakers like Buchardts or Dutch and Dutch 8Cs which have bass drivers on the back correct? I suspect this continues to hold true even for speakers which use boundary loading to improve bass?

Reason behind thought:
Currently I live in a very well insulated apartment built this decade. I have a subwoofer facing me. I'm fairly happy with my thundering bass and my neighbours hear nothing.
In 2 weeks I'm moving to a 70s build terraced house. I highly suspect the firewall will not be as good at isolating noise from the neighbours. Additionally I am very close to buying a set of Dutch and Dutch 8Cs. So to my question:

On the other side of the front wall will the volume of bass be the same regardless of if I have a front facing subwoofer, or 4 rear facing subwoofers providing the volume is the same at the listening position? i.e. will I piss off my neighbours worse buying a set of Dutch and Dutch 8Cs than simply using my existing 12" subwoofer?

I suspect not, but I'm wondering if I'm missing something. It just doesn't feel right pointing 4 subs at my neighbours.
 

Ultrasonic

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I believe you're correct that it won't matter which way the drivers are facing from the point of view of annoying your neighbours. In terms of subwoofers it can make a difference to the sound you hear though since in changes where the point that the sound radiates omnidirectionally from is located (which is where the center of the driver is, not the center of the subwoofer). I have my subwoofer facing a side-wall as it gives the best response at the listening position this way.

I'd hold off on buying speakers like the D&Ds until you've moved, because if you find the soundproofing of your new home is poor you may find you are never really able to benefit from the bass extension they offer.
 
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Frgirard

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I have a shower thought that I wanted to run by someone who understands this better than I do.

Most speakers especially in the bass (sub 150Hz) region have spherical radiation pattern. So on theory the volume for these lower frequencies is the same standing in front of the woofer as behind (opposite side of the speaker). This would then equally apply to speakers like Buchardts or Dutch and Dutch 8Cs which have bass drivers on the back correct? I suspect this continues to hold true even for speakers which use boundary loading to improve bass?

Reason behind thought:
Currently I live in a very well insulated apartment built this decade. I have a subwoofer facing me. I'm fairly happy with my thundering bass and my neighbours hear nothing.
In 2 weeks I'm moving to a 70s build terraced house. I highly suspect the firewall will not be as good at isolating noise from the neighbours. Additionally I am very close to buying a set of Dutch and Dutch 8Cs. So to my question:

On the other side of the front wall will the volume of bass be the same regardless of if I have a front facing subwoofer, or 4 rear facing subwoofers providing the volume is the same at the listening position? i.e. will I piss off my neighbours worse buying a set of Dutch and Dutch 8Cs than simply using my existing 12" subwoofer?

I suspect not, but I'm wondering if I'm missing something. It just doesn't feel right pointing 4 subs at my neighbours.
The cardioid on the dutch doesn't work under 100 hz.

In the doc available on the website and in the link below

https://www.google.com/amp/s/www.soundonsound.com/reviews/dutch-dutch-8c?amp
 
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garbz

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I'd hold off on buying speakers like the D&Ds until you've moved

Yes I absolutely will, though for other reasons (it's going to be a ****show for the coming few weeks). But I hardly doubt the D&D will leave me wanting. Going from B&W 805s + 12" cheap sub, to these will not disappoint me even in a non-ideal scenario :) I'm not buying them for the bass alone.

Thanks.

The cardioid on the dutch doesn't work under 100 hz.

Yes that was precisely the reason behind my post. Only the midrange is cardioid so the neighbours may hear lower sound overall, but it's the rear-firing subwoofers on them that made me wonder if pointing the subs in their direction makes it worse for some reason. But everything I know about acoustics (which admittedly isn't too much) points to it making no difference. IMO a bass drone is more annoying than actually hearing someone's music.
 

Frgirard

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Yes I absolutely will, though for other reasons (it's going to be a ****show for the coming few weeks). But I hardly doubt the D&D will leave me wanting. Going from B&W 805s + 12" cheap sub, to these will not disappoint me even in a non-ideal scenario :) I'm not buying them for the bass alone.

Thanks.



Yes that was precisely the reason behind my post. Only the midrange is cardioid so the neighbours may hear lower sound overall, but it's the rear-firing subwoofers on them that made me wonder if pointing the subs in their direction makes it worse for some reason. But everything I know about acoustics (which admittedly isn't too much) points to it making no difference. IMO a bass drone is more annoying than actually hearing someone's music.
The direction of the woofer has nothing to do with the sound nuisances.
The speaker in bass Frequencies (until 400 hz for Genelec, 500Hz for Dutch! ) is an emissive sphere.

You need to find if the issues are due to an aerial transmission, a solidian transmission or the both.
 

kyle_neuron

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The rear-facing subs will be a very slight bit louder at the position of the back wall if we were talking free-space, if only because they’re physically closer by the depth of the cabinet.

However, bass ‘collects’ at the boundaries and corners more so, regardless of placement. If the boundary wall isn’t suitably dense (ideally with an air gap or composite makeup for low sound transmission index value) then the room might ‘not exist’ as far as the lowest notes are concerned.

Your best bet is to borrow a sub and make friends with the neighbours. Ask them how loud it is, and make it clear you’re experimenting with them in mind; in reality, a large portion of noise management is making the potential complainants feel heard, and responding in some manner. Simply having a ‘hotline’ that is answered by a person in authority at an event can drastically reduce the number of complaints, as an example.

Sadly, if you’re finding the low stuff is a nuisance then there’s not much you can do beside very expensive building work. Even the most effective cardioid subs or arrays require a reasonable distance (ideally > 1 metre) from any boundary to work properly:
https://www.prosoundweb.com/counterintuitive-cardioid-subwoofers-can-be-a-bit-claustrophobic/2/
 

hex168

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You could go dipole bass. The advantages are 1) you could use the side nulls to reduce bass going to neighbors 2) The lack of room pressurization can also result in less bass leaving your apartment. Neutral: transmission modes through the floor, etc. still need to be addressed. Negative: You need a LOT of cone area for a dipole sub. Fortunately it can be done cheaply; five of these $25 15" per side should do (Caveat: I have not tried this but the source is reputable):
http://www.mfk-projects.com/my_projects/Projects 2015/MCM woofers.html

https://www.newark.com/mcm-audio-select/55-2974/15-woofer-with-poly-conerubber/dp/80R7013?st=15
 

Joecarrow

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I think that dipole subwoofers are one of those things where "in theory" there would be less bass leaving the room, or the bass would be directional, but in practice I have not found my LX521 with dipole subs to be any less prone to sending bass throughout the house. I have also found extremely limited changes in measured or perceived bass when rotating the subwoofer section in a small room. I'm sure that in a much larger room the directivity of the dipole would come into play, but below the schroeder frequency I haven't noticed that as much as I would have thought.

What I have found to be helpful is to use tactile transducers such as those from Clark Synthesis. By building a low platform to support your seat and sending a version of the subwoofer signal through it you can create the impression of hearing bass that seems louder and lower and more visceral. I've found that you do need to tune it carefully with a DSP to integrate it seamlessly, but in my experience it can add a great deal of satisfaction without annoying the neighbors.
 
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Ultrasonic

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But I hardly doubt the D&D will leave me wanting. Going from B&W 805s + 12" cheap sub, to these will not disappoint me even in a non-ideal scenario :) I'm not buying them for the bass alone.

My point was more that you might feel you'd wasted money on capability that you weren't able to use. I really hope your new home works out well acoustically though :).
 

dasdoing

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it is actualy pretty simple. the farer away from you, the louder the sub has to play, the louder it will be on the other side.
 
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garbz

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My point was more that you might feel you'd wasted money on capability that you weren't able to use. I really hope your new home works out well acoustically though :).

Oh I got the point, just saying the bass isn't the reason I've got a keen eye on these, rather it was more of a concern. Small living room, speakers designed to be placed against a front wall, built in DSP so I can retire the one that only works on digital and not on my vinyl collection, they have quite a lot going for them.

it is actualy pretty simple. the farer away from you, the louder the sub has to play, the louder it will be on the other side.
That much was obvious :) I was more wondering if there was any giggery pokery around pointing a sub at the wall. But it sounds like there's not,
 

dasdoing

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That much was obvious :) I was more wondering if there was any giggery pokery around pointing a sub at the wall. But it sounds like there's not,

the thing is, what most anoys the neighbours is not the direct sound, but the standing waves. and those will form idependently from where the sub is. so it all comes down to how loud it plays.
 

dasdoing

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thats why even reflective room lovers should at least have a ton of absorbtion on the backwall. it will bring those most anoying longitunal modes down.
 

Ultrasonic

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@dasdoing I don't really think what you've said in your last three posts is correct.

What matters to neighbours is sound 'leaking' into their room which is unrelated to the standing wave pattern that exists in the listeners room.

Unrelated to neighbours, where a subwoofer is in a room will affect it's interaction with the room and therefore the response at the listening position. Also, EQ very much does address ringing - reducing peaks in the bass resposne with EQ also reduces the time it takes for sound at that frequency to decay to any absolute level threshold you choose.
 

dasdoing

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@dasdoing I don't really think what you've said in your last three posts is correct.

What matters to neighbours is sound 'leaking' into their room which is unrelated to the standing wave pattern that exists in the listeners room.

Unrelated to neighbours, where a subwoofer is in a room will affect it's interaction with the room and therefore the response at the listening position. Also, EQ very much does address ringing - reducing peaks in the bass resposne with EQ also reduces the time it takes for sound at that frequency to decay to any absolute level threshold you choose.

it is what I hear. the ringing frequencies are the most anoying in other rooms, even EQed. the whole ring goes down, obviously, but it continues there. try it out in your shower. find some strong resonant frequencies with your voice. than lower yor voice. it will continue anoying. ringing personaly feels like the whole rooms is vibrating to me. and even though that is not realy the case, it on the other hand is the case, because that is how bass moves from one room to the other behind a wall.
the low note of this track will make my whole apartment "vibrate". it doesn't matter how low I play it.
obviously any frequency will propagate at some point, but
a) the ringig frequencies have that anoying sustain even after EQ
b) even EQed they continue louder at the wall
So my point is that if you are slowly rising the volume, the first frequencies that will anoy on the other sides are those of the standing waves
 

dasdoing

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we must not forget that wall is not wall in every place. AFAIK in the US there are no massive walls between rooms. there will be much less ringing, and much more sound propagation. I can imagine that behind a drywall you can almost get the whole low frequencie spectrum throug the wall, because it is kind of transparent.
this is something very little adressed here. US rooms are much diferent from the rest of the world.
 

Ultrasonic

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I'm afraid I still disagree @dasdoing . I use EQ to control bass resonances in my own room and know very well how it performs.

Walls in the US are not wildly different from those in the UK going by your last post by the way.
 

Ultrasonic

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I'll just add an important flip-side to consider with EQ, which is that If it is used to boost ouput at dips in the frequency response then this will likely make noise issues for neighbours worse. Note also that applying EQ filters to only attenuate rather than boost can still have the same effect, if it subsequently results in the sub volume/gain being increased.
 

dasdoing

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well, personaly I have hear all kind of crazy stuff with room modes when I walk trough my AP while music is playing in my cave.
for example, iirc the very first mode of my room will actualy produce a second harmonic outside of my room.
also part of the anoyence of the ringing is the harmonics. extreme rooms can always teach so much, so here is an extreme example:
you can EQ whatever you want, that chord will always be there singing along
 
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