EQ or Bass Traps

[Sithlord]

Hi all. I'm having an issue with bass where I believe I have a bass spike in one point in my room. The room size is roughly 3m wide and 4.5 metres long (Polished wood floor boards with large rug in the middle) with the subwoofer placed at the front right of the room just in front of the main speaker with a wall behind the sub. The sub in question is the SVS-B4+ and it's pretty big so room placement is limited to 2 positions. I have tried placing the sub behind the listening position (3 recliners at back of room) but it sounded far too localised. Where it is atm it sounds good but when a big bass moment happens, it sounds like the sub is right behind me (back left of the listening position) so in other words it's becoming localised. I want the bass to disappear so I'm contemplating 2 alternatives. 1 buy a Behringer EQ (model DSP1124p) or 2 buy some Bass traps/room accoustic panels. I can find the EQ for about $180AUD (Australian dollars) or I can try these product solutions found here:

http://www.primacoustic.com/australis.htm

http://www.primacoustic.com/razorblade.htm

http://www.primacoustic.com/scandia.htm


I'm currently waiting for an e-mail back from the sales contact on the website for my country to quote me a price for each. I would appreciated any advice regarding the above mentioned ideas. Thanks in advance.

[warnerwh]

The treatments you posted will not help in the bass. Those type bass absorbers don't do anything down low where you need the help. The Behringer will do a good job of ridding your room of peaks and is a true bargain.

For very little money you can make some diy bass traps. My hard drive crashed and hopefully someone here will post Thomas' website. This site has excellent pictures so you can see how easy it is.

Another good place to learn is realtraps.com. Ethan has videos there too. If you Google diy bass traps or go to the Acoustics circle at Audio Circle you can learn more about acoustics and especially bass traps. Do a search here too on diy bass traps.

No matter what bass traps should be your first choice being as you can get away with putting them in your room. I've used similar bass traps to those you posted and to be honest they're worthless. You can buy commercial bass traps or diy, which I recommend because it's so easy and inexpensive.

If you can put a bass trap in each corner where they're most effective that is what you should do. I know putting two more traps in my room, for a total of 4, helped considerably.

Damping first reflection points is also highly recommended. This will help the soundstage and clarity significantly.

Room acoustics play a huge role in the sound of your system. They're right up there with speakers. It's hard to imagine until you do it yourself or take your own speakers to a well treated room. After 35 years in this hobby I've learned the room is the first consideration. Nothing else comes close such as amps or cd players and especially wire. For the money room treatments/bass traps offer an excellent return on your investment.

Best Wishes

[kgveteran]

Is that SVS passive with an outboard amp? If so, what amp are you using ? What is your crossover point ?

Most of the time localized sounds out of a sub can be two reasons, first is the crossover point is too high.Second, the sub is distorting and you are hearing harmonics of the distorted frequency.

I ask about the sub amp because that sub is a brute and should not be giving away its position unless the amp is clipping and it is an outboard amp.If it has a plate amp disregard this amp stuff because it's meant to be with that sub.

You can always get a PEQ (behringer 1124p) to quell the room nodes, but you have to be able to see them.That requires a TRueRta program so you can run sweeps and see the response you want.There is tone of info on programs that help tune a room.

Good luck KG

PS How's the weather down below ?

[RobP]

I agree with KG, you should see what your room response is before you make any purchases. This will take all of the guesswork out of the game. Also, you should use an EQ only after the room is treated properly.

[howburger]

Some links for you

I agree that room treatments can be of much more value than the equipment at the point of diminishing returns. I've asked for some advice on several boards and got some logical responses and some that basically ridiculed me for wanting to do it myself without any room response measurements. With bass traps in the corners and absorption at first reflection points, it may not be perfect, but it will be head-and-shoulders above what it was without it. Use the treatments first and then equalize with the Behringer.

http://home.comcast.net/~jtgale01/diy2.htm

http://www.geocities.com/jonrisch/a1.htm

http://www.geocities.com/jonrisch/basstrap.htm

http://www.teresaudio.com/haven/traps/traps.html

Harold

[Sithlord]

Thanks guys for your suggestions. The Sub is being powered by a Quest amp (Aussie brand) it's bridged to output 2100watts so power isn't a problem and I've never heard that sub clip or the amp. The amp does have a clip light and I've never seen it plus it will cut out if it does encounter problems. I will definatly check out the DIY bass traps but I'm really not one of those guys that is a handy man nor have I had extensive experience using tools ops: . The system I'm running is the M&K S-5000 THX setup with dipole rears and the sub crossover is set to 80 as per the THX spec. The pre-amp is the Arcam AV8 and under speaker sizes is set to THX which automatically sets the crossover to 80. I will investigate the links provided and see how easy it is to make them myself. Thanks again for the suggestions.

Update: What about these products:

http://www.soundacoustics.com.au/Ram3.htm

http://www.soundacoustics.com.au/panels.htm

Would these help with my problem? They seem well priced.

As to the weather here it's hot. I dont like summer very much. 8)

[kgveteran]

I agree that room treatments can be of much more value than the equipment at the point of diminishing returns. I've asked for some advice on several boards and got some logical responses and some that basically ridiculed me for wanting to do it myself without any room response measurements. With bass traps in the corners and absorption at first reflection points, it may not be perfect, but it will be head-and-shoulders above what it was without it. Use the treatments first and then equalize with the Behringer.

http://home.comcast.net/~jtgale01/diy2.htm

http://www.geocities.com/jonrisch/a1.htm

http://www.geocities.com/jonrisch/basstrap.htm

http://www.teresaudio.com/haven/traps/traps.html

Harold

I built Jon's bass traps and have great results.I need two more though.Time based programs are needed to measure decay times and such.I have not yet ventured there.The traps I built are 48" X 18".

[ToddAnisman]

Another good place to learn is realtraps.com. Ethan has videos there too. If you Google diy bass traps or go to the Acoustics circle at Audio Circle you can learn more about acoustics and especially bass traps. Do a search here too on diy bass traps.


Best Wishes

I second the notion of Realtraps. Ethan Weiner has impressed the heck out of me over on the HC boards with his knowledge of the physics of Room acoustics.

My personal philosophy, which is much more empirical in the sense of trial nad error, is to fix the room rather than use EQ. EQ should be used to fine tune a room. I personally am not a fan of Beheringer, but many people have used it sucessfully.

I am a big fan of proper delays in the speakers so that the audio hits you at the proper timing. Also the timing of speakers (when using separates) is absolutely crucial. Granted. my experience comes from larger stages, but you would be amazed at what timing can do to the sound- Really open things up. Especially triming in the C-LR relationship- most people's CCh is much closer to the listener than the L-R speakers, thus the C audio can get to you before- thus potentially causing comb Filltering- which often can cause the smearing that many people describe. Also, most living rooms are either too absorbent or too active- keep in mind that most of the sound you hear is refleted sound as opposed to direct- so your bass problem could actually be a problem in your mids or high freq's.

The problem you are describing sound much more like standing waves than EQ- the fact that you describe a "spike" implied that the bass response elsewhere is OK. Teh Behringer could potentially help that, but tend to think that some well placed diffusion might solve it easily.

Hope this helps-

-Todd A.

[Sithlord]

Thanks Todd for your advice. I will be purchasing some accoustic panels (4) to see how they go.

http://www.soundacoustics.com.au/panels.htm

I can get them for $33 (Australian dollars) each instead of $48. Should get them in a week or so and will post my impressions. I intend on getting some bass traps as well for the same price. Will keep everyone posted. Thanks again for your thoughts.

[kgveteran]

On the time based correction issue, try to adjust delay time(in your HT processor) in the "Meter" setting.It will offer greater control of distance the feet.

[Kal Rubinson]

Thanks Todd for your advice. I will be purchasing some accoustic panels (4) to see how they go.

http://www.soundacoustics.com.au/panels.htm

I can get them for $33 (Australian dollars) each instead of $48. Should get them in a week or so and will post my impressions. I intend on getting some bass traps as well for the same price. Will keep everyone posted. Thanks again for your thoughts.

Those seem to be foam panels and, in general, it will take much, MUCH more foam to accomplish anything in the low bass compared with compressed fiberglass. They may not seen so inexpensive after all.

Note that the soundacoustics tests are of a room kit and, even so, do not bother to test below 100Hz. "The philosophy behind the development of these kits was to make professional studio acoustic treatment affordable. We decided to base these kits on the 75mm high spec SA600/75 rather than the 40mm AT600/40 due to their superior absorption of frequencies down to 200Hz."


Kal

[ToddAnisman]

Those seem to be foam panels and, in general, it will take much, MUCH more foam to accomplish anything in the low bass compared with compressed fiberglass. They may not seen so inexpensive after all.

Note that the soundacoustics tests are of a room kit and, even so, do not bother to test below 100Hz. "The philosophy behind the development of these kits was to make professional studio acoustic treatment affordable. We decided to base these kits on the 75mm high spec SA600/75 rather than the 40mm AT600/40 due to their superior absorption of frequencies down to 200Hz."


Kal

Agreed. Although I am thinking he needs diffusion as opposed to absorption....

Think breaking up the surfaces and creating angles, as opposed to sucking it all up with panels.

-Todd A.

[Kal Rubinson]

Agreed. Although I am thinking he needs diffusion as opposed to absorption....

Think breaking up the surfaces and creating angles, as opposed to sucking it all up with panels.

True but the OP said: "I'm having an issue with bass where I believe I have a bass spike in one point in my room." Perhaps he needs to measure or assess before spending money.

Kal

[ToddAnisman]

True but the OP said: "I'm having an issue with bass where I believe I have a bass spike in one point in my room." Perhaps he needs to measure or assess before spending money.

Kal

Good Point. I have a great little tool for measurement that comes in handy- the Phonic PAA-3. It actually graph very close to the Dolby hardware used on our Dubb stages, so I was prety impressed. Will also measure RT60, and can be uploaded to computer... Nice tool for a few hundred.... Just FYI.

-Todd A.

[Sithlord]

Hmmm I wish I had read these new posts before I placed and paid for the 4 panels oh well. So will these help in anyway with the overall sound? I would like to think that they will offer some assistance to the soundstage not necessarly bass.

So Kal will it be a waste of money to buy a couple of these then:

http://www.soundacoustics.com.au/Ram3.htm

Will they offer any real benefit to bass control in a small to medium room?

Todd that Phonic PAA-3 retails for $399.00US when I searched for it on Google. Thanks for mentioning it though.

Thanks in advance :T

[Kal Rubinson]

Hmmm I wish I had read these new posts before I placed and paid for the 4 panels oh well. So will these help in anyway with the overall sound? I would like to think that they will offer some assistance to the soundstage not necessarly bass.

So Kal will it be a waste of money to buy a couple of these then:

http://www.soundacoustics.com.au/Ram3.htm

Will they offer any real benefit to bass control in a small to medium room?

Some? Yes but, imho, not much. Foam is the wrong tool for low frequencies. If your problem is below 100Hz, you need large, thick fiberglas panels or blocks. Or you can fill the room with foam. :roll:

Kal

[ToddAnisman]

Hmmm I wish I had read these new posts before I placed and paid for the 4 panels oh well. So will these help in anyway with the overall sound? I would like to think that they will offer some assistance to the soundstage not necessarly bass.

So Kal will it be a waste of money to buy a couple of these then:

http://www.soundacoustics.com.au/Ram3.htm

Will they offer any real benefit to bass control in a small to medium room?

Todd that Phonic PAA-3 retails for $399.00US when I searched for it on Google. Thanks for mentioning it though.

Thanks in advance :T

Y'know Sith...we never asked you about your setup here ....
Your sub is powerful, but is it crossed over/Bass managed properly? If you're having a "spike" then it is possible that you are having comb filtering because of your bass management; If your sub is producing frequencies that are also being produced by your mains, then you would see the symptoms of what you are describing as well...especially at the crossover point. It's not enough to just filter the sub channel. Any Channel that feeds into the sub in a Bass management scenario must then be filtered as well; this is often overlooked or ignored. For example, My system is an M&K rig with 2550's across the front and 5310 Sub. The Mains are powered by Bryston 9BSt. I have 2 Ashly Protea EQ's. When I started graphing the room, I was noticing that there were serious Peaks in the low end Due to standing waves etc...But then I realized it was right on the crossover point on the Bass Management. Once I adjusted and took this into consideration, the tuning was much easier, with much less radical gain adjustment on adjoining Freq's.

Tell us more about your setup...

-Todd A.

[Sithlord]

Todd if you look at my posts you will see that I have already posted my system specs. I also run an M&K setup using the S-5000 THX system which is now a discontinued line. It was the model below their best which was the powered speakers. The Sub is being powered by an external amp brand Quest (Australian brand) 2100watts bridged. My pre-amp is the Arcam AV8 and has been configured to THX spec under speaker setup so the crossover is set automatically to 80. All 5 speakers are being powered by a Krell TAS amp and my EX channels x2 also M&K (not sure of model number ex demo from Hi-Fi store) are powered by as Rotel 1050 amp. So with this config no bass is being produced by anything else other than the Sub. Hope this helps.

[ToddAnisman]

Todd if you look at my posts you will see that I have already posted my system specs. I also run an M&K setup using the S-5000 THX system which is now a discontinued line. It was the model below their best which was the powered speakers. The Sub is being powered by an external amp brand Quest (Australian brand) 2100watts bridged. My pre-amp is the Arcam AV8 and has been configured to THX spec under speaker setup so the crossover is set automatically to 80. All 5 speakers are being powered by a Krell TAS amp and my EX channels x2 also M&K (not sure of model number ex demo from Hi-Fi store) are powered by as Rotel 1050 amp. So with this config no bass is being produced by anything else other than the Sub. Hope this helps.

Sith- Totally my bad...sorry about that.

OK, so cool, sounds like your system is setup well- just a question- setup to THX spec, but which one? PM3 or Full rooom? Or is there a THX spec for HT? just curious.

are there any rental places in Australia that rent RTA's??

-t

[kgveteran]

Y'know Sith...we never asked you about your setup here ....
Your sub is powerful, but is it crossed over/Bass managed properly? If you're having a "spike" then it is possible that you are having comb filtering because of your bass management; If your sub is producing frequencies that are also being produced by your mains, then you would see the symptoms of what you are describing as well...especially at the crossover point. It's not enough to just filter the sub channel. Any Channel that feeds into the sub in a Bass management scenario must then be filtered as well; this is often overlooked or ignored. For example, My system is an M&K rig with 2550's across the front and 5310 Sub. The Mains are powered by Bryston 9BSt. I have 2 Ashly Protea EQ's. When I started graphing the room, I was noticing that there were serious Peaks in the low end Due to standing waves etc...But then I realized it was right on the crossover point on the Bass Management. Once I adjusted and took this into consideration, the tuning was much easier, with much less radical gain adjustment on adjoining Freq's.

Tell us more about your setup...

-Todd A.

Todd,
Are you just cascading filters to create a steep slope ? Sounds like you are trying to get a complimentary 24db/oct at the XO point. I prefer a "Dry" XO point like a 24db/oct at the main/sub XO point.By dry, I mean steep with little hump on either side.Funny how the THX XO point with processors gives the sub 24db/oct and the main 12db/oct....I guess they are banking on the mains to have a 80hz hipass acoustical sealed rolloff to add to the electronic 12db/oct for a total of 24db.......

[Sithlord]

OK, so cool, sounds like your system is setup well- just a question- setup to THX spec, but which one? PM3 or Full rooom? Or is there a THX spec for HT? just curious.

Hey Todd. What I mean by this is that under the setup for speakers on the AV8 you can select THX EX which will automatically set the speakers to their spec that being all speakers to small. Also theres a THX setup for the Sub and the crossover is set to 80 automatically (from the speaker setup at the start) and theres an option that asked if the sub is THX Ultra 2 capable (goes below 20hz) I selected yes for that. The boundary gain is currently set to off. The weird thing is if during a movie I select THX Ultra 2 EX my sub output drops dramatically and I lose alot of bass. I normally watch movies with the selection of DD 5.1+DDPL2x. That was a new addtion with the firmware for the AV8 and sounds the best IMO.

are there any rental places in Australia that rent RTA's??

I'm sorry I dont know what RTA's are ops:



Kgveteran your post goes far beyond my knowledge ;x( but it sounds interesting. God this hobby can get full on 8)

[collectslps]

DIY bass traps was a recent project for me. Checked numerous sites and benefited from alot of good suggestions. Instead of using fiberglass, I bought 4 4" x 2' x 4' batts of bonded recycled cotton. Bought 1/4" & 1/2" thick strips of wood as framing, joined with brads & gorilla tape. Used a good quality wood glue to set each batt in its frame. Covered with a nice looking jute from a remnants store. 2 of the traps lean against the front wall corners. With 3" wide wood spacer in between, the other 2 are a combined bass trap box at my rear wall. REALLY WORKS! Total cost $300

[Sithlord]

Thats excellent collectslps. Do you have any pictures of them? Would really like to see them.