how to eliminate boomy bass...

[manu4panjab]

Is your speaker rear firing port type? If yes, then 9 inch is way too less. Increasing that 2 feet should produce wonders. Please experiment. Even for non-rear firing, it's still good to keep sufficient space behind (and to the sides of the speakers).
Joshua

yup rear port type...i'll try today n will post later ,see if it helps but 2 feet is very inward lemme try a reasonable distance n from sides both atleast 2 feet

 

[manu4panjab]

easiest way is to introduce a dual channel graphic equaliser and reduce the bass curve on the channel producing boomy sound.....or else go for proper acousic treatment or relocation of your speaker system.....)

i like to do proper acoustic treatment but afraid from the cost ..don't know how much it'll cost ...

 

[himadri]

Manu
Speaker placement is the only effective way to get rid of bass boominess if you dont want to go for equalization.
For me the Cardas method worked the best Cardas Audio
Cheers
Himadri

 

[manoj.p]

If you have a subwoofer and crossed it at 80 Hz or even may be 100 Hz can help. Especially if the right side of room is causing the issue. You can move the Hsu sub to some other location where it does not sound boomy. This way, you are moving the sound to a place where it won't have reflection or min room effect.

I don't think the spikes will help, unless the speaker is not exactly flat to floor and causing vibrations. Also, I think spikes work best with carpet floor to give better speaker grip. I haven't used spikes so can't comment for sure.

For bass traps, it can come cheaper if you are looking into DIY. Although you will need very thick, 6"+ to absorb the low frequencies. There are tons of info on diy bass traps.

 

[darshanjoshi]

If you are using an AVR, try doing bass settings.
It helps a lot without compromising the bass and mid range. Set the speakers to small (very important) and change the crossover to 80 hz. Trust it helps a lot.

 

[ShaQ.Blogs]

There are many suggestions being given. But I fail to understand how can this be, without knowing...
1. Room Dimensions! Also what is the room made of (cement walls I presume, and flooring)?
2. I notice you have gone the separates way. Does it have room correction - Audessey? Audessey does a nice job correcting room bass, again it is only so much that it can do.

The room would be the biggest problem. Eventually to give advice on how to rectify this is impossible without measurements, measurements, measurements and measurements!!! You could have slight improvements trying a couple of different stuff & maybe get luck too... but, unlikely.

I noticed you have a really good HiEnd HSU sub (The sub suggests that you have a pretty big room). Is the sub playing when you have boomy bass? This is one of the biggest problems with FS. Placement becomes crucial, more so if room has acoustics problems in the bass regions (significant in small-medium sized rooms). If you had a sub or if you can crossover early and *not play bass through the FS* then good placement of the sub can rectify bass to some extent. Placing a sub to obtain good bass is not hard, but placing an FS to get good bass....thats a different challenge entirely.

post #23 is a good place start! That wont solve it entirely because it is most likely a room problem....which I am sorry to say wont go away easily. Room treatment in the form of bass traps is the solution. Again unless we have some real measurements to know what is the problem, difficult to fix it.

 

[trittya]

Manu, I hate to say this but this a perpetual problem with all rear-ported speakers in small rooms with not enough space for the bass waves to propagate and subsequently dissipate. However, sometimes port woof aka noise is the main culprit at times. Ports are a way for the manufacturer to tune, augment and optimize the response with the same hardware. Yes spikes will help to an extent in improving the bass response but in no way will they mitigate the effect of standing waves emanating from the rear ports. LIke ajay said, sealing the bass port kills the very character of the speaker which the manufacture strived to get the best of with the same hardware and hence the same budget, so it never works as it virtually amounts to re-inventing the wheel. Bass traps do work but they too take a lot of space and are neither easy nor cheap to build. let me know if you are interested.

 

[ShaQ.Blogs]

Manu, I hate to say this but this a perpetual problem with all rear-ported speakers in small rooms with not enough space for the bass waves to propagate and subsequently dissipate.

Correct me if I am mistaken, but Isnt the polk rti a5 front firing?
Usually backfiring have an even more significant issues with distance to back wall.

If you are using an AVR, try doing bass settings.
It helps a lot without compromising the bass and mid range. Set the speakers to small (very important) and change the crossover to 80 hz. Trust it helps a lot.

sorry, but setting speakers to small usually in most receivers and amps, it internally overrides the crossover. When set to small it defaults to around 80, and tweaking it is no use in most receivers. If you want to set crossover then set it to large!!!

If you have a subwoofer and crossed it at 80 Hz or even may be 100 Hz can help.

Yes. But only to some extent. It is easier to get good tight bass from good sub placement than through an FS. One of the not so well discussed horrors of getting an FS. Placement of FS in some rooms becomes extremely crucial, especially for bass.

Especially if the right side of room is causing the issue.

It is not just a problem of right or left. It is the whole room.

I don't think the spikes will help, unless the speaker is not exactly flat to floor and causing vibrations. Also, I think spikes work best with carpet floor to give better speaker grip. I haven't used spikes so can't comment for sure.

A nice thick plank of wood under the sub & FS would help to some extent. MDF is great, with supports under the board.
If you can get this, then it wud be great. But nuthing great about it that DIY cannt achieve.

For bass traps, it can come cheaper if you are looking into DIY. Although you will need very thick, 6"+ to absorb the low frequencies. There are tons of info on diy bass traps.

Thick rigid fibreglass, 2 panels of 6" each or one 12" panel would do great. But you would require to do this on every damn corner, and sides. Again, without measurements dont expriment with your money

One which could help a lot if you room is not too big, try these in order.
1. Bring the speakers front. Experiment, 2 - 6 ft from back wall. Even moving 6 inches in any direction can make big difference. Watch the side walls, the ratio of distance from side walls to back walls is crucial. (But dont be rigid with anything. Experiment, experiment & experiment)
2. Crossover bass away from the main speakers to the sub, experiment with different crossover frequencies. Do not play all the bass from the FS. This is mainly because it is easier to place a sub. So before you do that, you need to place the sub right!!
3. Treat the wall behind you. This can help a lot, more so in a smaller room.
4. Bass traps.
(Before you do 3 & 4 you need measurements to understand what is the problem area before you spend your hard earned money)


Trying to find a link which I bumped across recently, it can help a lot. Will post it If i do find it.

 

[manu4panjab]

thanks all of u to post ....i have tried spikes but no effect still boomy from right side of the room(even swapping fs each other )
guys my hsu uls-15 won't create any bomminess or echo its just fs the thing is when i play music i turn off the sub n in av processor to none n fs to full otherwise all are at 80hz n small ,only when playing fs to full create boominess sub is great no problem in that department
so today i contact an acoustician from chandigarh but it cost me one lacs.....dammm.he talked about acoustic tiles n not in my range ...
i guess i have to sold polk rtia5 n get bookshelves ....

 

[HTuser]

Sorry to Bump up this thread, i have a query in this line

I have the same FS speakers and SVS PB12 Plus subwoofer. I don't have boomy sound issue from the FS standers (Crossover at 60Hz). Room size is 32x12x10(LxWxH). But there is a boominess for low frequency sound from Subwoofer.

I found the following info from another post in this forum. Which mentions about the thickness of sound trap to be installed in the backside of the room.

------------
343 100 = 3.43 4 = 0.86 meter
343 90 = 3.81 4 = 0.95 meter
343 80 = 4.29 4 = 1.07 meter
343 70 = 4.90 4 = 1.23 meter
343 60 = 5.72 4 = 1.43 meter
343 50 = 6.86 4 = 1.72 meter
343 40 = 8.58 4 = 2.14 meter

So if you want to trap all the frequencies from 100Hz & above, the trap depth has to be more than 0.86 meter. If you want to trap all the frequencies above 60Hz, the trap depth has to be more than 1.43 meter ..... and so on. Its advisable to have a rear wall trap of 1.1 meter so that all the directional frequencies above 80Hz are totally kept under control.
---------------

My question is if I install a bass trap of 1.1 meter depth to absorb all frequencies above 80Hz, will there be any effect on a sound signal of 60Hz or 40Hz. Will the boominess due to them will be reduced or there will not be any change. In case the boominess will reduce, how much it will reduce approximately - like 50% or 20%

 

[anm]

1.1 meter! that's too expensive consider the price of the real estate

 

[HTuser]

I know

Consider it as a hypothetical question

Many acoustic treatments uses 2" or 4" boards or bass traps, but none of them are more than 1 meter in depth.

I wanted to find out whether the room treatments are having any effect on frequencies below 80Hz

 

[manoj.p]

To take care of peaks and dips in the below 80Hz frequencies, one can either use very thick bass traps, like 10" or something. That will make the room sound dead though and the subwoofer amp will have to overwork to get more db.

A better option is to use another or more than one subwoofer. It will cancel out peaks and dips of the first sub and bring the frequency response more level. If you have two subs, then it can be put in the mid of front and back wall. if there are four, then at midpoints of each wall. These are the optimum positions. Even two subs in the front, with equidistance from listening position will work, only that its not the optimum. Using multiple subs won't make the system louder, because its level is set down after matching it with rest of the speakers. It will although make bass very smooth, and better seat to seat consistency. If one has to spend the money on bass traps, it can be very well used on buying another sub.

The best way to start on this whole thing is to invest in a SPL meter, use it with Room Eq Wizard and find out the room response. That will make the situation more clear and the solution will be better informed. Otherwise, its only shooting in the dark and see if it hits the target. We spend lacs on audio equipment but the SPL meter goes a long way in setting the equipment right. Even a Radioshack SPL meter is a good start and its only $50.

As for OP, he mentions the boomy sound is only from the right speaker and if he is using the sub, then there is no boominess. So, what's stopping you using it that way? The Hsu sub is top quality, I believe its bass is quite better than compared to your mains anyways.

 

[sdurani]

guys my hsu uls-15 won't create any bomminess or echo its just fs the thing is when i play music i turn off the sub n in av processor to none n fs to full otherwise all are at 80hz n small ,only when playing fs to full create boominess sub is great no problem in that department

Why are you turning off the subwoofer when playing music? Your speakers don't cover the bottom octave, so you need a subwoofer to get full frequency response. This shouldn't change whether you're watching a movie or listening to music. If you're not getting any boominess when using the sub, then continue using it when listening to music.

 

[sdurani]

Even a Radioshack SPL meter is a good start and its only $50.

The analogue RadioShack SPL meter is being closed out for only $15. Just have to find someone to pick it up at a local store and mail it to India.

 

[BLASTO]

@Manu..

I have the same room problem and have no option to treat it as it is currently my living room..
My hifi purchase was aimed at my new house with bigger room for hifi which I will be moving in a year.. But currently struck with a rented house with no scope of 'treatment'.

Hence Iam trying to get rid of the room effects digitally..

Refer to my thread below..
http://www.hifivision.com/av-enhancers-room-acoustics/20348-drc-suggessions.html

This krk ergo device costs like $350 in ebay now (mrp $700). Iam in two minds to try it out.. This device is custom built for the purpose and can be recaliberated if you change the room and hence not a throw away device IMO. Apparently it removes 80% of issues from the untreated room according to reviews. Not bad IMO for the price.

Now to wait and see if anyone returns from the US.

 

[sdurani]

Many acoustic treatments uses 2" or 4" boards or bass traps, but none of them are more than 1 meter in depth.

I wanted to find out whether the room treatments are having any effect on frequencies below 80Hz

They are, but hardly any. 2" boards will do full absorbtion down to around 500Hz; 4" boards are effective down to around 200Hz. Keep in mind that thicker absorbers don't abosrb more, they just absorb at lower frequencies. So a 6" absorber won't absorb more at 1kHz than a thinner board, but it will absorb down to 100-125Hz.

Sound travels by air molecules bumping into each other until they collide with our eardrums (where our brain converts the vibrations into sound). Absorbers work by slowing down the moving air, converting the velocity into heat. As such, you're better off placing absorbers where air velocity is high, and the absorber can be more effective.

Think of firing a bullet into a wall. At the wall, the bullet is at maximum pressure (so much pressure that it punches a hole in the wall), but zero velocity (it's not moving). How about when the bullet was a few inches from the wall? Then you had lots of velocity. Likewise, sound is at max pressure but zero velocity at a room boundry (wall). However, a few inches before it hits the wall, sound is moving pretty fast.

Want to make a 2" board absorb almost like a 4" board? Mount it a couple of inches away from the wall, where it can take advantage of the higher velocity. The absorber gets two opportunities to slow down the sound: as the sound is going towards the wall AND as it is bouncing back into the room.

BTW, if you decide to make home-made absorbers, don't make them too thick. Beyond 8-10" or so, sound has trouble going all the way through a rigid fibreglass panel and will partially bounce back. At certain frequencies, the density starts acting like a reflector more than an absorber. At that point, you're better off using fluffy fibreglass insulation than rigid fibreglass boards (besides, the fluffy stuff is much cheaper). But you're not going that thick anyway.

Whatever thickness you end up buying (or making), keep the air-gap trick in mind.

 

[BLASTO]

Other option is to digitally alter your files so that they are 'custom' built for your room.

The input file will be a file with full unaltered frequencies while the out put file will have the problematic frequencies' volume reduced so that it sound natural when the room increases the volume.. That is the theory.


IMO, this is time consuming and not worth the effort. This might give proof if the room is the culprit however and also will help you check if the digital room correction works in your room..

Try out,

(((acourate)))

 

[manoj.p]

The analogue RadioShack SPL meter is being closed out for only $15. Just have to find someone to pick it up at a local store and mail it to India.

I was wondering if you plan to show up in this thread.


That RS meter is damn cheap. May be I should go and pickup one, just as a backup.

 

[manu4panjab]

To take care of peaks and dips in the below 80Hz frequencies, one can either use very thick bass traps, like 10" or something. That will make the room sound dead though and the subwoofer amp will have to overwork to get more db.

A better option is to use another or more than one subwoofer. It will cancel out peaks and dips of the first sub and bring the frequency response more level. If you have two subs, then it can be put in the mid of front and back wall. if there are four, then at midpoints of each wall. These are the optimum positions. Even two subs in the front, with equidistance from listening position will work, only that its not the optimum. Using multiple subs won't make the system louder, because its level is set down after matching it with rest of the speakers. It will although make bass very smooth, and better seat to seat consistency. If one has to spend the money on bass traps, it can be very well used on buying another sub.

The best way to start on this whole thing is to invest in a SPL meter, use it with Room Eq Wizard and find out the room response. That will make the situation more clear and the solution will be better informed. Otherwise, its only shooting in the dark and see if it hits the target. We spend lacs on audio equipment but the SPL meter goes a long way in setting the equipment right. Even a Radioshack SPL meter is a good start and its only $50.

As for OP, he mentions the boomy sound is only from the right speaker and if he is using the sub, then there is no boominess. So, what's stopping you using it that way? The Hsu sub is top quality, I believe its bass is quite better than compared to your mains anyways.

u r right sir but its not from right speaker it from right side of the room (even i swap speakers thought right speaker was damaged but same..) why i use fs to full when listening to music coz i just carpeted my floor n install spikes too n read somewhere that u first set ur mains properly with 0 boominess n start by setting them full so u can dead lock the bass from fs in plain of the centre channel speaker i have achieved 80% success rate by ading spikes n toe-in fs but still my right ear starts feeling heavy when playing bass heavy music so it means still problem in right side of the room...