Troublesome 50Hz, 100Hz

lscangus

New Member
Oct 24, 2018
24
15
3
31
#1
Hi All, I am new to this forum and I had a very trouble boomy bass very specifically at 50Hz, so just want to ask if anyone can share with me some experience on how am I going to solve that? I have basic diffraction columns on the corner of the room, but still hasn't got luck on solving the problems. One phenomenon I have noticed is the bass is only boomy when I was sat down at the listening position. When I stood up, is flat! Anyone has any idea on this?

I have attached a RTA of the system at the listening position ( sat down ), a plan of the listening room ( 3.8Meters floor to ceiling )
 

Attachments

kodomo

Active Member
Apr 26, 2017
331
246
43
#2
If you also write your ceiling height, I can roughly calculate your rooms modes. You have a rectangular room and it would be easy to calculate and treat acoustically. I think it would be better if you had actual chunky bass traps in the rooms four corners. Your room has a schroder frequency at around 160-180hz (I guess, I dont know your ceiling height) so whatever plays below that frequency is mostly dictated by your room. You have some treatments, but I guess they may be a little random and not applied according to calculations.

Sitting or standing difference can be because of different reasons. Like first order crossovers create this effect as well as the room cancellations happen in 3 dimensions. You can have a diffusor or absorber combo for the front and back wall at your ear height.
 

adyc

VIP/Donor
Jan 6, 2013
404
20
18
#3
Try to move the speaker or sitting position. If no luck, try a pair or two of AVAA bass traps.

BTW, is your speaker G1 or G2?
 
Likes: PeterA

lscangus

New Member
Oct 24, 2018
24
15
3
31
#4
If you also write your ceiling height, I can roughly calculate your rooms modes. You have a rectangular room and it would be easy to calculate and treat acoustically. I think it would be better if you had actual chunky bass traps in the rooms four corners. Your room has a schroder frequency at around 160-180hz (I guess, I dont know your ceiling height) so whatever plays below that frequency is mostly dictated by your room. You have some treatments, but I guess they may be a little random and not applied according to calculations.

Sitting or standing difference can be because of different reasons. Like first order crossovers create this effect as well as the room cancellations happen in 3 dimensions. You can have a diffusor or absorber combo for the front and back wall at your ear height.
Hi kokomo, the ceiling height is 3.8meters. I have placed diffraction panels on the 1st reflection surfaces on the side wall, other than that, is mostly 10cm thick absorbing materials. I have placed them with listening test, so far
 

kodomo

Active Member
Apr 26, 2017
331
246
43
#5
Hi kokomo, the ceiling height is 3.8meters. I have placed diffraction panels on the 1st reflection surfaces on the side wall, other than that, is mostly 10cm thick absorbing materials. I have placed them with listening test, so far
Hello, you have a room mode at 50.7hz and it is effective at the attached photo of your room model. Also do not put your speakers 1.7m from the front wall. It would also create a 50hz cancellation.

Your corner treatments are not effective. Use corner bass traps on 4 corners of the room at least 40cm deep (better to go 50cm) and preferably filled with knauf 044 earthwool ecosse covered with fabric. This is lower density earthwool (as the depth rises in the acoustic treatment, it is better to go low density).
 

Attachments

lscangus

New Member
Oct 24, 2018
24
15
3
31
#6
Hello, you have a room mode at 50.7hz and it is effective at the attached photo of your room model. Also do not put your speakers 1.7m from the front wall. It would also create a 50hz cancellation.

Your corner treatments are not effective. Use corner bass traps on 4 corners of the room at least 40cm deep (better to go 50cm) and preferably filled with knauf 044 earthwool ecosse covered with fabric. This is lower density earthwool (as the depth rises in the acoustic treatment, it is better to go low density).
When you say 1.7M from the Front wall, means the speaker has to be more than 1,7meters away from the wall? Also, any drawings of the bass trap which you have described?
 

kodomo

Active Member
Apr 26, 2017
331
246
43
#7
When you say 1.7M from the Front wall, means the speaker has to be more than 1,7meters away from the wall? Also, any drawings of the bass trap which you have described?
There are several factors working together so, just moving the speakers beyond 1.7m may free you from front wall cancellations but your speakers may end up in room mode which would then cause another problem. I was just guessing the reasons of your 50hz suck out and if your speakers are at 1.7m it could have been one of the reasons.

Corner trapping is easy, cheap and most effective. Do it to all 4 corners of your room. Check out this construction, but I recommend to make it deeper and with lower density earthwool: http://webblab.sk/home-studio/3-corner-bass-traps

ps. your rooms schroeder frequency is at about 150hz.
 

PeterA

Well-Known Member
Dec 7, 2011
5,523
412
83
North Shore of Boston
#8
Try to move the speaker or sitting position. If no luck, try a pair or two of AVAA bass traps.

BTW, is your speaker G1 or G2?
I would start by getting a desk chair with rollers and slide it back and forth listening for smoothest bass performance. Then locate the listening couch in that location. Then play around with speaker positioning and toe in. I agree that bass traps should also be tried. Send the drawings and graph to ASC or some other company and they will advice you on type, number, and location of traps.
 

lscangus

New Member
Oct 24, 2018
24
15
3
31
#9
I would start by getting a desk chair with rollers and slide it back and forth listening for smoothest bass performance. Then locate the listening couch in that location. Then play around with speaker positioning and toe in. I agree that bass traps should also be tried. Send the drawings and graph to ASC or some other company and they will advice you on type, number, and location of traps.
Thank you so much for your reply. I have tried numerous location with my mic, There will be no "boom" as long as I am not on the centre axis between the speakers and also in the middle of the room. =[
 

lscangus

New Member
Oct 24, 2018
24
15
3
31
#10
There are several factors working together so, just moving the speakers beyond 1.7m may free you from front wall cancellations but your speakers may end up in room mode which would then cause another problem. I was just guessing the reasons of your 50hz suck out and if your speakers are at 1.7m it could have been one of the reasons.

Corner trapping is easy, cheap and most effective. Do it to all 4 corners of your room. Check out this construction, but I recommend to make it deeper and with lower density earthwool: http://webblab.sk/home-studio/3-corner-bass-traps

ps. your rooms schroeder frequency is at about 150hz.
That looks huge! I have found a few bass trap, which is smaller and they have stated very effective at around 50-60 hz.... should I give it a go and see what's what? I guess once I have the 50hz sorted, the 100 hz will be kind of sorted too?
 

lscangus

New Member
Oct 24, 2018
24
15
3
31
#11
Try to move the speaker or sitting position. If no luck, try a pair or two of AVAA bass traps.

BTW, is your speaker G1 or G2?
I really wouldn't want to get the active bass trap, I would really prefer something passive.

Is the G1
 

kodomo

Active Member
Apr 26, 2017
331
246
43
#12
That looks huge! I have found a few bass trap, which is smaller and they have stated very effective at around 50-60 hz.... should I give it a go and see what's what? I guess once I have the 50hz sorted, the 100 hz will be kind of sorted too?
Can you share those bass traps here so we can see. If it is not a membrane based trap specifically tuned to 50hz or some other specific way to deal with the problem then it won't be effective. There are a lot of claims on acoustic products that have false claims. It is very hard be smaller size than I stated to work those frequencies.
 

lscangus

New Member
Oct 24, 2018
24
15
3
31
#13
Can you share those bass traps here so we can see. If it is not a membrane based trap specifically tuned to 50hz or some other specific way to deal with the problem then it won't be effective. There are a lot of claims on acoustic products that have false claims. It is very hard be smaller size than I stated to work those frequencies.
O1CN01CrPjhj1gxJ7q7OiSz_!!0-rate.jpg_400x400.jpg

Looks something like this
 

kodomo

Active Member
Apr 26, 2017
331
246
43
#14
You mean that gray column! Unless there is an active component in it that, it doesn't have a chance to be effective enough at 50hz. Even if you had many of them.

50hz has a wavelenght of 6,8m. As a rule of thumb for porous absorbers, its thickness has to be at least 10th of the wavelength so 68cm to be exact. It also has to be covering enough area so that it is effective. So at least your four corners. This will certainly solve the 50hz and 100hz problem.

So if you think the ones on that page are huge, you would be shocked when I tell you to actually make them deeper than those! You can design the cover of it to look like it is part of the room without making it a visual problem.

This is what physics dictates. The other passive solution is tuned absorbers but they are effective only in certain frequencies, I think a wideband bass absorption is better with your room. It is also cheaper than buying nearly any branded acoustic product and there are nearly none that can do this.
 
Likes: christoph

lscangus

New Member
Oct 24, 2018
24
15
3
31
#15
You mean that gray column! Unless there is an active component in it that, it doesn't have a chance to be effective enough at 50hz. Even if you had many of them.

50hz has a wavelenght of 6,8m. As a rule of thumb for porous absorbers, its thickness has to be at least 10th of the wavelength so 68cm to be exact. It also has to be covering enough area so that it is effective. So at least your four corners. This will certainly solve the 50hz and 100hz problem.

So if you think the ones on that page are huge, you would be shocked when I tell you to actually make them deeper than those! You can design the cover of it to look like it is part of the room without making it a visual problem.

This is what physics dictates. The other passive solution is tuned absorbers but they are effective only in certain frequencies, I think a wideband bass absorption is better with your room. It is also cheaper than buying nearly any branded acoustic product and there are nearly none that can do this.
Hi, thanks for the reply, the grey column is a dense polymer device weighting around 3.5KG, with "open resonance structure". It is tuned to absorb the frequency. 350x350x1200. I have asked to provide the absorption data and they have supplied me with this graph.
TB22VKwfoRIWKJjSZFgXXboxXXa_!!2901182171.jpg

I am also looking at the links for the DIY bass trap, looks good and simple to do also. But if this product does what it says on the tin, then it is very very attractive
 

kodomo

Active Member
Apr 26, 2017
331
246
43
#16
Hi, thanks for the reply, the grey column is a dense polymer device weighting around 3.5KG, with "open resonance structure". It is tuned to absorb the frequency. 350x350x1200. I have asked to provide the absorption data and they have supplied me with this graph.
View attachment 48580

I am also looking at the links for the DIY bass trap, looks good and simple to do also. But if this product does what it says on the tin, then it is very very attractive
This is a tuned trap for 63hz. See that its efficiency is 0.65 sabins at 126hz and 0.85sabins at 63hz. Having these may help, but you need a few and placed at the modes that match 63hz and 126hz. Here you can see the main places of problems for 63 and 126hz. Place the absorbers in the 4 corners and also the center of the side walls to be most effective. You can have 3 on top of each other in every room corner, and two at the sidewalls mid points. This is easy and ready made alternative and can solve your problems if their claims are right.
 

Attachments

kodomo

Active Member
Apr 26, 2017
331
246
43
#17
The corner bass traps that you can d.i.y. would be better if they are deep enough. They would not only address the two dips you have, they would also be working wide-band throughout your bass and mid-bass and will also shorten the decay time of the bass frequencies better than these resonators. They would also be cheaper as you will need a few of those resonators. Keep that in mind!
 

adyc

VIP/Donor
Jan 6, 2013
404
20
18
#18
I really wouldn't want to get the active bass trap, I would really prefer something passive.

Is the G1

These active bass traps will not connect to your audio system. It behaves like a passive bass traps. It occupies much less volume.
 

kodomo

Active Member
Apr 26, 2017
331
246
43
#19
I had half an hour off, so here is a sketch for you, it is not random, it is calculated. This layout seems to solve your problems. You would have about 0.6ms decay time and would not have much problems below 150hz (your rooms schroeder)

Further than this, you can add ceiling diffusors for more uniform and scattered decay sound. I recommend them on top of the carpet extending to top of you covering the seating area.
 

Attachments

Likes: christoph

lscangus

New Member
Oct 24, 2018
24
15
3
31
#20
I had half an hour off, so here is a sketch for you, it is not random, it is calculated. This layout seems to solve your problems. You would have about 0.6ms decay time and would not have much problems below 150hz (your rooms schroeder)

Further than this, you can add ceiling diffusors for more uniform and scattered decay sound. I recommend them on top of the carpet extending to top of you covering the seating area.
Hi Kodomo! very nice drawing! I wonder whats the dimension the bass trap needs to be?
 

About us

  • What’s Best Forum is THE forum for high end audio, product reviews, advice and sharing experiences on the best of everything else. A place where audiophiles and audio companies discuss existing and new audio products, music servers, music streamers and computer audio, digital to audio convertors (DACS), turntables, phono stages, cartridges, reel to reel, speakers, headphones, tube amplifiers and solid state amplification. Founded in 2010 What's Best Forum invites intelligent and courteous people of all interests and backgrounds to describe and discuss the best of everything. From beginners to life-long hobbyists to industry professionals we enjoy learning about new things and meeting new people and participating in spirited debates.

Quick Navigation

User Menu

Steve Williams
Site Founder | Site Owner | Administrator
Ron Resnick
Site Co-Owner | Administrator
Julian (The Fixer)
Website Build | Marketing Managersing