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Deadzone in studio
Old 5 days ago
  #1
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Deadzone in studio

In my room i have a dead spot where all bass disappears, my room is rectangle not to sure on measurements but i have tried moving the subwoofer around the room to try and get the best listening position but to no success, I have even tried placing the subwoofer in my listening position and moving round the room and placing it in the position it sounds best in but it still gives me a dead zone of bass, My seating position is in the middle of the room but if i go into a corner or a different place in my room the bass sounds really loud just not in the spot i want it to be in i also have basstraps and acoustic foam any help? thanks.
Old 5 days ago
  #2
Gear Addict
The acoustic foam is pretty much useless for bass, my advice is to stop fighting your room and work with it.

Think about this: you're trying to get the absolute worst sounding place in the room to sound the best. If you went camping, you would look around the field to find the best place to put your tent that you can get the pegs into the ground. The place you might want to camp could be waterlogged. You could spent weeks trying to add field drains to get rid of the water and then pitch your tent up knowing that it's still prone to flooding, or you could pitch up somewhere else and be off to a good start.

This worked great for me. I was trying to set up in a less than optimum listening position and I have 14 broadband absorbers in my room, it worked far better working with my room.

Fixing The Low End In Your Studio Without Knowing Acoustics — Acoustics Insider

In addition, I'm sure you can improve the acoustics at your current listening position, but it would take a lot of work and even then it would likely still be far from where you want it to be
Old 4 days ago
  #3
Gear Maniac
 

Quote:
Originally Posted by Jasonxolly View Post
In my room i have a dead spot where all bass disappears, my room is rectangle not to sure on measurements but i have tried moving the subwoofer around the room to try and get the best listening position but to no success, I have even tried placing the subwoofer in my listening position and moving round the room and placing it in the position it sounds best in but it still gives me a dead zone of bass, My seating position is in the middle of the room but if i go into a corner or a different place in my room the bass sounds really loud just not in the spot i want it to be in i also have basstraps and acoustic foam any help? thanks.
I'm assuming that your sub-satelite system/combination is correctly phase aligned.

Basstraps, besides made of the adequate material (density/gas flow resistance) and sufficient thickness, need also to be placed in the right spots to perform as basstraps.
So, if your "basstraps" can easily be lifted with one hand, they're probably not real basstrap material, to begin with (and foam is not useful at all for LF absorption).


To give you just the starting basics to treating your room:

-1. Place your monitors and sub as close as possible to the front wall.
(Do a search on "wall behind speaker cancellation").

-2. Find rockwool or glass fibre of about 50kg/m3 to 70kg/m3 and make you some panels of 10cm thick (20cm even better) and strap them across all corners of your room, including the corners between walls and ceiling.
The material itself is relatively cheap; it's the framing and fabric to make it look nice that may cost more money
The backwall may need some absorbing too, in most cases.

-3. Download the free REW (Room EQ Wizard) and learn to do some basic acoustic measurements, if you want to further treat your room and finetune.


Remember, this is just a basic and generic advice that I'm giving you here, but still a good STARTING POINT for solving the low frequency issues in your room.

I hope this helps you get started.
Success.
Old 4 days ago
  #4
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CJ Mastering's Avatar
Quote:
My seating position is in the middle of the room but if i go into a corner or a different place in my room the bass sounds really loud just not in the spot i want it to be in i also have basstraps and acoustic foam any help? thanks.
Getting your room to be as flat as possible is hard as F#$k! You may need more bass traps or you may need less of them. The good news is that many environments that have been tuned really well are rectangle. its the most common shape for a home studio.

I would get Bass traps made from Corning 703 or 705 and make sure they are 4" thick. I would also use the 703 or 705 for acoustic panels as well and they should be 2" thick.
For the average room 2' X 4' X 4" is a common bass trap size and 2' X 4' X 2" is a common acoustic absorption size. If you cannot afford them pre-made, they are dirt cheap if you purchase the DYI kits. I have made over 20 of them for a fraction of what they cost.
Old 4 days ago
  #5
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FreshProduce's Avatar
Quote:
Originally Posted by Prodba View Post

-1. Place your monitors and sub as close as possible to the front wall.
Can you elaborate as to why the OP should do this? I've heard many people argue that your monitors should be at least 1 ft from the wall. Placing your sub right up against a wall will certainly result in all types of wall noise, so I'm just trying to figure out why you're making this reccomendation.


?
Old 3 days ago
  #6
Gear Maniac
 

Quote:
Originally Posted by FreshProduce View Post
Can you elaborate as to why the OP should do this?
Hi,

I'll try to explain without getting too technical and/or longwinded (appologies in advance if I do not succeed in that last part ).

While speakers are effective in directing high(er) frequencies forward, they, by nature, emit lower frequencies also from the sides and back.
The frequency at which this non directional behaviour starts is related to the smallest dimension of the baffle; this phenomenon is called "baffle step".

For this reason multi driver speakers have a "baffle step compensation" circuitry to ensure more power is directed to the woofers, relative to the tweeters.
So, a speaker is manufactured to produce and consume relatively more power in the low end than in the higher frequencies, to compensate for the loss of half of the LF energy (6dB baffle step loss) through the back.

In fact, sitting in front of a speaker in free field, you're hearing only half of the low end energy that is being produced by the woofer, as half is going out the rear.
To produce the desired SPL level in the low end in front of the speaker, the amp needs to produce twice the necessary power needed for the low end, as half is going to be "wasted".

This is why you get a bass boost when you place a speaker backed up against a wall; because the LF escaping from the back is now forced back forward by the wall and doubling up (+6dB) with sound waves emitting from the front.

The bass attenuation that studio monitors have in their EQ section (advised when placed close to boundaries), is in fact nothing more than deactivation of the baffle step compensation.
This alone is a win, since your amps need to work less to produce the same volume and therefore more efficient.


And now the acoustics implications and to your question:

As may be clear now, the soundwaves emitting from the backside of the speaker will reflect from the front wall and "join" the waves coming out the front.
However, these reflected waves will be out of phase with the direct sound, depending on the distance between speaker (baffle) and the front wall; due to the difference in travel path length, compared to the direct signal.
This wall-behind-speaker-cancellation is not a standing wave, but complete cancellation of those lower frequencies.
The calculation goes as follows; (speed of sound÷distance to front wall)÷4* (*sine waves cancel when shifted 1/4 wavelength)

Using the formula you can see that the closer to the wall, the higher the calculated cancelling frequency gets.
The higher this potential cancelling frequency gets, the less problematic, because:
-1. The reflected wave gets partially blocked by the speaker cabinet itself.
-2. The higher frequency moves above the baffle step frequency, the aforementioned frequency at which a speaker starts emmiting from the back.

So, the closer to the front wall, the higher the POTENTIAL/CALCULATED cancelling frequency gets and eventually becomes a non issue, a mere theoretical cancelling frequency, since there will be no cancelling going on in reality, at those higher frequencies.

Quote:
Originally Posted by FreshProduce View Post
I've heard many people argue that your monitors should be at least 1 ft from the wall.
Of course, one is limted in how close one can place active monitors to the front wall by the cooling requirements for the backplate/amp.
It was not made enough clear by me that this is also a factor in the determination of; "as close as possible", but "at least one foot" is not really accurate, not acoustically, nor what cooling is concerned.

If one wants to place loudspeakers at distance from the front wall, with no front wall cancelling issues, the distance must be so great thag the cancelling frequency falls below the lower cut off frequency of the speaker.
So for a speaker going down to 40Hz, the distance to the front wall would need to be over two metres (> 7feet); (342÷40)÷4=2,14mtrs.

Quote:
Originally Posted by FreshProduce View Post
Placing your sub right up against a wall will certainly result in all types of wall noise,...
The sub close to the wall will have boost of course, which is is a good thing, since you'd need to drive it less hard, as explained above.
And that is why monitors/subs have those controls to adjust when placed in different spots.

However, if placing a sub against a wall causes "wall noises", then there's a problem with that wall, at least acoustically.


I hope that I managed to explain it in a comprehensive manner and answered your questions satisfactorily.

Regards,
Old 3 days ago
  #7
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FreshProduce's Avatar
Quote:
Originally Posted by Prodba View Post
Hi,

I'll try to explain without getting too technical and/or longwinded (appologies in advance if I do not succeed in that last part ).

While speakers are effective in directing high(er) frequencies forward, they, by nature, emit lower frequencies also from the sides and back.
The frequency at which this non directional behaviour starts is related to the smallest dimension of the baffle; this phenomenon is called "baffle step".

For this reason multi driver speakers have a "baffle step compensation" circuitry to ensure more power is directed to the woofers, relative to the tweeters.
So, a speaker is manufactured to produce and consume relatively more power in the low end than in the higher frequencies, to compensate for the loss of half of the LF energy (6dB baffle step loss) through the back.

In fact, sitting in front of a speaker in free field, you're hearing only half of the low end energy that is being produced by the woofer, as half is going out the rear.
To produce the desired SPL level in the low end in front of the speaker, the amp needs to produce twice the necessary power needed for the low end, as half is going to be "wasted".

This is why you get a bass boost when you place a speaker backed up against a wall; because the LF escaping from the back is now forced back forward by the wall and doubling up (+6dB) with sound waves emitting from the front.

The bass attenuation that studio monitors have in their EQ section (advised when placed close to boundaries), is in fact nothing more than deactivation of the baffle step compensation.
This alone is a win, since your amps need to work less to produce the same volume and therefore more efficient.


And now the acoustics implications and to your question:

As may be clear now, the soundwaves emitting from the backside of the speaker will reflect from the front wall and "join" the waves coming out the front.
However, these reflected waves will be out of phase with the direct sound, depending on the distance between speaker (baffle) and the front wall; due to the difference in travel path length, compared to the direct signal.
This wall-behind-speaker-cancellation is not a standing wave, but complete cancellation of those lower frequencies.
The calculation goes as follows; (speed of sound÷distance to front wall)÷4* (*sine waves cancel when shifted 1/4 wavelength)

Using the formula you can see that the closer to the wall, the higher the calculated cancelling frequency gets.
The higher this potential cancelling frequency gets, the less problematic, because:
-1. The reflected wave gets partially blocked by the speaker cabinet itself.
-2. The higher frequency moves above the baffle step frequency, the aforementioned frequency at which a speaker starts emmiting from the back.

So, the closer to the front wall, the higher the POTENTIAL/CALCULATED cancelling frequency gets and eventually becomes a non issue, a mere theoretical cancelling frequency, since there will be no cancelling going on in reality, at those higher frequencies.



Of course, one is limted in how close one can place active monitors to the front wall by the cooling requirements for the backplate/amp.
It was not made enough clear by me that this is also a factor in the determination of; "as close as possible", but "at least one foot" is not really accurate, not acoustically, nor what cooling is concerned.

If one wants to place loudspeakers at distance from the front wall, with no front wall cancelling issues, the distance must be so great thag the cancelling frequency falls below the lower cut off frequency of the speaker.
So for a speaker going down to 40Hz, the distance to the front wall would need to be over two metres (> 7feet); (342÷40)÷4=2,14mtrs.



The sub close to the wall will have boost of course, which is is a good thing, since you'd need to drive it less hard, as explained above.
And that is why monitors/subs have those controls to adjust when placed in different spots.

However, if placing a sub against a wall causes "wall noises", then there's a problem with that wall, at least acoustically.


I hope that I managed to explain it in a comprehensive manner and answered your questions satisfactorily.

Regards,
Excellent explanation!

Thank you for your time and consideration. I have heard people mention that phenomenon, however I haven't read such a comprehensive explanation before. Makes perfect sense in theory.. I just have to apply it practically for it to sink in completely.

Thanks again, friend
Old 3 days ago
  #8
Quote:
Originally Posted by Prodba View Post

-3. Download the free REW (Room EQ Wizard) and learn to do some basic acoustic measurements, if you want to further treat your room and finetune.
Topic:
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