Subwoofers and Bass Traps

[JkSpinner]

Hi all, over the last 6 months I have made many changes and adjustments to my 2 channel system, including room treatment.  I did not start with bass treatment as my room problem was lack of bass.   The most recent was the addition of a subwoofer for 2 channel, I added a REL S510.  Now I still have some more work to do with tuning, and positioning.  My SQ is pretty dam good, a little bassy with modern pop music, but about perfect for live Aussie rock.  So the SQ sounds great at the listening position, and in the media room, however other rooms carry that distinctive boom boom associated with subwoofers.  My son can struggle to study, and in some smaller rooms, closets, bathrooms toilets etc, it’s terrible.

Are bass traps the answer here, or something else.

[Satanica]

I think the short answer is NO. Because trapping real bass i.e. mid bass and low bass requires enormous devices, the kind that you probably don't want or can't facilitate in your room. Also, if you were to actually trap some bass, you might end up trapping waves that are destructive, so you end up with more bass in some areas.

[betty boop]

4 hours ago, JkSpinner said:

other rooms carry that distinctive boom boom associated with subwoofers.  My son can struggle to study, and in some smaller rooms, closets, bathrooms toilets etc, it’s terrible.

unfortunately this is near impossible to fix …it’s why multiplex theatres run subs that taper of at 40hz …lower bass carries ..only way to fix is lower output at lower freq ..

 

One other way in case it’s physically transferring from sub to room is isolating the sub … eg svs sells sub isolation that’s quite affordable and may be worth a shot?

https://www.svsound.com/blogs/subwoofer-setup-and-tuning/bad-vibrations-how-to-reduce-subwoofer-room-rattle-and-bass-bleed?

Or just lower volume …try headphones or get sound cancelling head phones for the child … though that doesn’t work for physical vibrations …

[Kaynin]

Yeah, not much you can do.  AVR's have a "night" setting for this issue, lowering bottom end output which is very effective.  Unless you integrate an AVR, a 2 channel set-up isn't your friend.

[JkSpinner]

40 minutes ago, betty boop said:

it’s why multiplex theatres run subs that taper of at 40hz

Thanks Al, would something like mini dsp help with this.

happy to lower the volume, as I mentioned I am still playing around with set up, inc volume, c/o and position.  
strange question, would two subs also help,  as with two subs, I hear you generally turn them down a little.

55 minutes ago, betty boop said:

head phones for the child

He is an adult child at Uni.

 

36 minutes ago, Kaynin said:

night" setting

I wondered what that setting was.  Perhaps a DSP device could assist with this

[wasabijim]

the home isn't a tradition Queenslander workers cottage style? it sounds leaky, no issue with bass washing around the room causing nodes and such, the walls/floors/ceiling are like a tent. great for SQ not so much everyone else in the house. 

[Kaynin]

1 hour ago, JkSpinner said:

I wondered what that setting was.  Perhaps a DSP device could assist with this

Maybe.  You’d have to have two settings, “day” and “night” and flick between the two - or have a “night” setting and be happy with reduced bottom end during the “day”.

[Hi-Fi Whipped]

14 hours ago, JkSpinner said:

I wondered what that setting was.  Perhaps a DSP device could assist with this

I would say definitely being able tune the bass frequencies using DSP will help. I only use Dirac Live to integrate my subs and it works very well, no boomy bass leaking through the house.

[almikel]

On 13/11/2024 at 2:37 PM, JkSpinner said:

The most recent was the addition of a subwoofer for 2 channel, I added a REL S510.

If you've connected the Rel sub using the high level speaker inputs, a miniDSP won't help.

 

If the sub level sounds too high on pop music, I would dial it back on the Rel - you should never really notice a sub is working until you turn it off and notice something is missing - subtlety is key.

 

On 13/11/2024 at 2:37 PM, JkSpinner said:

however other rooms carry that distinctive boom boom associated with subwoofers.  My son can struggle to study, and in some smaller rooms, closets, bathrooms toilets etc, it’s terrible.

Are bass traps the answer here, or something else.

Sound isolation/sound proofing is an entirely different challenge compared to improving the "in room" sound with acoustic treatment - and can even work against each other.

Eg a room with solid brick walls can have excellent isolation (ignoring flanking paths), but reflects all the sound back into the room, requiring more treatment  

 

If you have EQ capability on a source - eg music played from a laptop, you could try some bass cut down low.

Or tone controls on your amp.

As said above, if your sub is coupled to say a timber floor, that can generate audible vibrations throughout the rest of the house - use some isolation pucks...not spikes - spikes couple vibrations.

 

Unfortunately you can't easily change the level of isolation a room has after construction.

Lots of info on soundproofing here - just to help you understand the challenge: 

https://www.soundproofingcompany.com/soundproofing-101

 

 My family understands that it's OK to tell me to turn the music down.

 

Mike

 

[andyr]

58 minutes ago, almikel said:

If you've connected the Rel sub using the high level speaker inputs, a miniDSP won't help.

 

Not quite, surely, Mike?

 

Sure, if you've used the "REL sub connection method" (rather than a good sub connection method) ... then all of the amp's output is going to the mains and the sub(s).  And the sub's LP filter sets its roll-off point.

 

But if you put, say, a 2x4HD miniDSP unit before the power amp ... you could implement some LF shelf cuts to limit the low end going into the sub(s) (at frequencies which are too low to worry the mains).  IE. LP shelves something like:

• -4dB @ 40Hz
• -4dB @ 30Hz
• -4dB @ 20Hz.

 

But that kinda defeats the whole point of having sub(s)!   

 

58 minutes ago, almikel said:

If the sub level sounds too high on pop music, I would dial it back on the Rel - you should never really notice a sub is working until you turn it off and notice something is missing - subtlety is key.

 

^   ^   ^  what the man sez!

 

58 minutes ago, almikel said:

Sound isolation/sound proofing is an entirely different challenge compared to improving the "in room" sound with acoustic treatment - and can even work against each other.

Eg a room with solid brick walls can have excellent isolation (ignoring flanking paths), but reflects all the sound back into the room, requiring more treatment  

 

If you have EQ capability on a source - eg music played from a laptop, you could try some bass cut down low.

Or tone controls on your amp.

As said above, if your sub is coupled to say a timber floor, that can generate audible vibrations throughout the rest of the house - use some isolation pucks...not spikes - spikes couple vibrations.

 

Unfortunately you can't easily change the level of isolation a room has after construction.

Lots of info on soundproofing here - just to help you understand the challenge: 

https://www.soundproofingcompany.com/soundproofing-101

 

All good info for JkS.  

 

58 minutes ago, almikel said:

 My family understands that it's OK to tell me to turn the music down.

 

What a nasty family you have!  

 

[JkSpinner]

Thanks all, I have moved my sub from the corner, which has reduced the bass in the media room.  As this is a reasonably new purchase, I need to spend some time fine tuning and finding the right position for it.  I purchased the REL only for 2 channel, however since it is connected via the high level connections, and front speakers set to large on the AVR, it also adds to the HT.  I agree with the subtlety is the key.  I was never a fan of subs for 2 channel, I always thought that large powerful amplifiers and speakers were the key, would luv a set of speakers with 12 or 15” woofers, but I am learning that a well blended sub most likely offers more benefits.

i did not have it loud, so it was not that bad in the other rooms, but you could really notice the boom in some rooms, especially with pop music.  I mainly listen to rock, live rock, and acoustic rock, although my tastes are changing, and my system and sub sound quite nice for that, but a little Dua Lipa on the weekend really showed the flaws.  I will spend some time this weekend dialing it in a little better.

the house is a concrete floor, brick veneer house.

[jamiebosco]

On 13/11/2024 at 2:37 PM, JkSpinner said:

Hi all, over the last 6 months I have made many changes and adjustments to my 2 channel system, including room treatment.  I did not start with bass treatment as my room problem was lack of bass.   The most recent was the addition of a subwoofer for 2 channel, I added a REL S510.  Now I still have some more work to do with tuning, and positioning.  My SQ is pretty dam good, a little bassy with modern pop music, but about perfect for live Aussie rock.  So the SQ sounds great at the listening position, and in the media room, however other rooms carry that distinctive boom boom associated with subwoofers.  My son can struggle to study, and in some smaller rooms, closets, bathrooms toilets etc, it’s terrible.

Are bass traps the answer here, or something else.

Im not sure exactly what you are asking, but room treatment/bass traps etc can only help with the sound quality INSIDE the room, and even then it takes very thick traps to do anything under 100hz (10" + thickness)

Sound transfer to other rooms in the house (?) - especially bass frequencies  - is  completely different and needs totally different technology ie build a room with a room or a  sealed concrete bunker style room, or a detached building etc

 

but maybe i'm misunderstanding the Q

[almikel]

On 14/11/2024 at 5:45 PM, andyr said:

Not quite, surely, Mike?

don't call me Shirley  

 

On 14/11/2024 at 5:45 PM, andyr said:

But if you put, say, a 2x4HD miniDSP unit before the power amp ... you could implement some LF shelf cuts to limit the low end going into the sub(s) (at frequencies which are too low to worry the mains). 

Agreed that would work - I made an assumption (possibly incorrect?) that @JkSpinner didn't have the capability to insert a miniDSP between his pre-amp and power-amp.

 

On 14/11/2024 at 5:45 PM, andyr said:

What a nasty family you have!  

I have the same issue as @JkSpinner - I have a lightly constructed room where lots of sound leaks out, especially low bass.

My family is remarkably tolerant  - when I crank the stereo, they mostly put up with it.

14 hours ago, JkSpinner said:

 I was never a fan of subs for 2 channel, I always thought that large powerful amplifiers and speakers were the key

I've always been a fan of subs for 2 channel - place your mains for best imaging and place your sub or subs for smoothest bass across the listening position/couch.

 

14 hours ago, JkSpinner said:

would luv a set of speakers with 12 or 15” woofers

I run stereo Acoustic Elegance TD18s as my mid bass crossed to my sub - the bass slam is epic with minimal overhang in my room with the bass "reasonably" under control.

You're in Brisbane - message me if you would like to come and listen.

 

14 hours ago, JkSpinner said:

but a little Dua Lipa on the weekend really showed the flaws.

It's not flaws - Dua Lipa was just mixed differently which included more low bass.

This is what tone controls are useful for.

You can't expect every album to have the same mix.

 

I dial flat the bass EQ when listening to Angus and Julia Stone as those guys don't need any bass boost, but I'm happy to tweak the EQ to taste anytime.

 

15 hours ago, JkSpinner said:

the house is a concrete floor, brick veneer house.

A concrete floor is pretty inert - so unlikely you'll have structural vibrations going through the floor to other rooms.

You'll have loads of acoustic transmission through walls and flanking paths - you can't easily fix this.

 

The free options are:

• dial the bass back on the Rel
• turn the overall volume down

cheers,

Mike

[JkSpinner]

On 15/11/2024 at 10:01 PM, jamiebosco said:

but maybe i'm misunderstanding the Q

Perhaps Jamie, the question was maybe not clear, but I think the description was.  Either way, I think I received the information I needed.

Bass traps etc will not help the bass issue in other rooms, it will most likely only assist the bass issue in the media room.

i am playing around with moving the sub around the room to see if I can get a good enough sub eq, without effecting the other rooms such as the toilet.  Also playing around with volume and cross over.

will see how I go

Edited November 17, 2024 by JkSpinner

[andyr]

Given you said this, JkS:

 

On 15/11/2024 at 7:25 AM, JkSpinner said:

the house is a concrete floor, brick veneer house.

 

Maybe you should try an isolating platform under the sub - so it no longer sends vibrations down into your concrete slab ... which travel into other rooms?

 

[JkSpinner]

On 15/11/2024 at 10:03 PM, almikel said:

• dial the bass back on the Rel
• turn the overall volume down

Come on Mike - I only just put the subwoofer in, how can you expect me to turn it down just yet, I am already thinking of a second sub, then I might turn it down a a bit.  
I am just sitting here listening to Cold Chisel doing a live cover of Dragon Sunshine from the Ringside album, and I can tell you the bass is about perfect, could even be turned up a bit for that live effect.

in all honesty, I have been moving the sub around a bit, playing around with the volume and cross over, so will continue to play around, the bass in the other rooms does not bother me at all.

[JkSpinner]

On 16/11/2024 at 6:29 PM, andyr said:

isolating platform under the sub

Hi Andy, happy to try this, I have isolation under everything else, and the most noticeable difference was with placing isolation under the speakers.

not that sure whether isolation will make that much of a difference to the other rooms, I suspect that the bass is travelling through the walls, not the concrete, but I could be wrong.  It’s a front firing sub, with a downward facing passive.

[almikel]

17 hours ago, JkSpinner said:

the bass in the other rooms does not bother me at all.

Lol - gold!

I try not to annoy the rest of the family too much, and they cut me a bunch of slack to crank it loud - just not too often, too late at night, for too long...

 

17 hours ago, JkSpinner said:

Come on Mike - I only just put the subwoofer in, how can you expect me to turn it down just yet, I am already thinking of a second sub, then I might turn it down a a bit.  

I get it - but very often people buy a new sub, and they want to "hear the sub"...

...IMVHO good sub integration is about subtlety - not knowing the sub's turned on until you turn it off and the bottom octave disappears.

 

Post new measurements with/without the sub? the bass should just extend lower with the sub on, not have a higher level on the frequency response...adjust smoothing in the measurement to remove the lumpiness to see what's going on.

 

If the sound inside the room is nicely balanced across the frequency range (with your choice of room curve), if too much bass is leaking out throughout the house, you don't have many options

 

On 13/11/2024 at 2:37 PM, JkSpinner said:

My son can struggle to study

Obviously you need to minimise impact to your son's study time!

On 13/11/2024 at 2:37 PM, JkSpinner said:

in some smaller rooms, closets, bathrooms toilets etc, it’s terrible.

It can be surprising what some "natural household damping" in those rooms can achieve, like filling closets with clothes/blankets/towels...effectively adding absorption treatment to the rooms where it's an issue...

 

Obviously reduce flanking paths as much as possible by closing doors/windows of the listening room, and the rooms the sound is leaking to...unfortunately it won't reduce bass transmission much  

 

Welcome to the joys and tyranny of lightly constructed rooms - they're much easier to achieve great "in room" bass with less treatment, but the bass leaking out goes places that annoys people

 

cheers,

Mike

[almikel]

Everyone went out this afternoon, so I cranked up the stereo.

 

When they came home, I kept the stereo at the same level, then went and did a quick sanity check with the family - everyone was OK with the level 

Hilariously the bass coming through into their rooms would have annoyed me...clearly I'm less tolerant than they are!

 

Mike

[betty boop]

On 22/11/2024 at 7:42 PM, JkSpinner said:

Hi Andy, happy to try this, I have isolation under everything else, and the most noticeable difference was with placing isolation under the speakers.

not that sure whether isolation will make that much of a difference to the other rooms, I suspect that the bass is travelling through the walls, not the concrete, but I could be wrong.  It’s a front firing sub, with a downward facing passive.

hi JK,  further up in this  thread i posted a link from SVS... not sure if read it, but this is exactly they suggested amongst other things. the seven have an inexpensive solution for this. 

[JkSpinner]

7 hours ago, betty boop said:

hi JK,  further up in this  thread i posted a link from SVS

Hi Al, I did read this, and noticed it was a reasonably inexpensive solution, especially when you look at some others.  I also watched a video where REL do not  recommend isolation.  I will do some more tuning / moving the sub around, then take a look at isolation.

[almikel]

On 24/11/2024 at 6:14 AM, JkSpinner said:

I also watched a video where REL do not  recommend isolation.  

wow - really?

If you can find the link, can you send it to me please?

 

I'm trying to think of a scenario where coupling the vibrations of a sub to the room floor would be a good thing - I can't think of any!

 

A sub sitting on carpet on a concrete slab floor won't couple vibrations much, but I'm astounded that Rel don't recommend isolation?...I'd be fine with "not usually needed"

 

Mike

 

 

Edited November 25, 2024 by almikel
clarification

[JkSpinner]

8 hours ago, almikel said:

If you can find the link, can you send it to me please

https://rel.net/blog/2021-10-26/q-a-with-john-hunter/why-rel-acoustics-doesnt-recommend-subwoofer-isolation-platforms/#:~:text=When you isolate you're,couple out into the room.
 

I actually have not watched this as yet

[almikel]

On 26/11/2024 at 6:45 AM, JkSpinner said:

https://rel.net/blog/2021-10-26/q-a-with-john-hunter/why-rel-acoustics-doesnt-recommend-subwoofer-isolation-platforms/#:~:text=When you isolate you're,couple out into the room.
 

I actually have not watched this as yet

Interesting video - I don't necessarily agree with what John Hunter from Rel says.

 

In one part of the video Rel says (I'm paraphrasing) they spend a lot of time carefully calibrating the height of the feet to get the bass exactly right, and increasing the height by 2 inches (50mm) reduces deep bass and increases mid bass.

At 80Hz, the wavelength is 4.3m (and obviously longer at lower freq). Adding 50mm extra height to the sub won't impact the Speaker Boundary Interference Response (SBIR) or the modal response of your room to any discernable degree.

 

In another part they mention "I understand that there are times if you live in a for example, a small apartment, and you’re trying to prevent bleed through from down below, you may need to do something extreme. You may need to put down a foam pad or something," - I think they meant, "bleed through from your sub to the apartment on the floor below"...

...Which is what we're suggesting may assist your case, if the sub on the slab floor is sending vibrations through the slab to the rest of the house.

 

cheers,

Mike

[JkSpinner]

17 hours ago, almikel said:

suggesting may assist your case

I agree Mike,  I am still going through the moving the sub around the room.  I did notice the change in bass when I installed Isoacoustic feet under my speakers, so it may just be  a solution that works for me.

although, my bass problem is going to get bigger for watching movies.  I took advantage of the SVS discounts to replace a 20 year old 10” rattle sub with a new 13” sub, sole purpose “ home theatre.  When watching movies, I have two subs active, the new SVS sub connected to my HT receiver, and the real connected to my 2 channel power amp.  Even with my old sub, having two subs just filled the room with bass.