Author Topic: Setting up a HT Den in a square room: Compressive Feeling In My Ear  (Read 9150 times)

Offline wechnivag

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #255 on: November 09, 2019, 10:42 »
Thanks bro, I think given the size of the thing, I can only fit one..
I'm trying out the Art Novion Siena W Subtrap standalone which can handle a 43-46Hz wave.

https://artnovion.com/product-categories/9-bass-trap/products/320-sub-trap-range
@ bro wechnivag
The one you posted is for a higher frequency..
The sub trap is one big mama.. so it will just about fit in that vital corner..

Siena Sub Trap - Stand Alone
- 736x892x400mm

That's the one that can hit the 44hz tuning frequency. What I'm saying is don't expect miracles with just one... 2 is minimum. 4 is better.... Iron law..

One single trap will just leave you feeling frustrated. Now you are stuck with this giant column thing that doesn't really do much..

One way of placing is along the front and back wall - ceiling interface. That reduces the floor footprint and space impact..
Since your room is square, the sidewall - ceiling interface works too.

So you can fit 2 on the front or back wall corners, and 4 on the ceiling.. Gets expensive real fast. Not to mention the space, and aesthetics.

When you consider that, the active trap option becomes really attractive. And the fact that they have good resale value and easy to move. Multiple, Bulky traps, quite a nightmare.

Diy is the other option. A good diy job will match or even beat the other options. But the time invested, and actually the hundreds of hours of reading and learning and experimenting, to gain the necessary knowledge to wrestle with the laws of Physics , and come out on TOP. Most concede, battered and bruised. Definitely not for everyone.

An analogy I like to use. Think of treating the room as paving the road. Otherwise the Ferrari speakers /subs will just be spinning wheels and sliding around in the dirt track . No amount of dsp EQ (electronic traction control) will help you set good lap times or maximise performance of the system.

Having said that, Bryan did an absolutely incredible job with the calibration. You literally cannot get better results that that even if you fly in the best expert calibrator, money no object.

So any acoustic treatment to the room that you put in will be an improvement on top of the stellar calibration job. But the calibration will need to be redone after treatment.

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« Last Edit: November 09, 2019, 11:46 by wechnivag »

Offline petetherock

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #256 on: November 09, 2019, 11:05 »
That's the one that can hit the 44hz tuning frequency. What I'm saying is don't expect miracles with just one... 2 is minimum. 4 is best.... Iron law..

One will just leave you feeling frustrated. Now you are stuck with this giant column thing that doesn't really do much..

One way of placing is along the front and back wall - ceiling interface. That reduces the floor footprint and space impact..
Since your room is square, the sidewall - ceiling interface works too.

So you can fit 2 on the front or back wall corners, and 4 on the ceiling.. Gets expensive real fast. Not to mention the space, and aesthetics.

When you consider that, the active trap option becomes really attractive. And the fact that they have good resale value and easy to move. Bulky traps will be a nightmare.

Diy is the other option. A good diy job will match or even beat the other options. But the time invested, and actually the hundreds of hours of reading and learning and experimenting, to gain the necessary knowledge to wrestle with the laws of Physics , and come out on TOP. Most concede, battered and bruised. Definitely not for everyone.

An analogy I like to use. Think of treating the room as paving the road. Otherwise the Ferrari speakers /subs will just be spinning wheels and sliding around in the dirt track . No amount of dsp EQ (electronic traction control) will help you set good lap times or maximise performance of the system.

Sent from my X9009 using Tapatalk


Thanks bro
We identified one corner with the issue. Anyways, I can only afford one item: one sub or one trap... that's it.. $$$
I know.... I was once a perfectionist, but this is one deep pocketed hobby... and I know it as well as most of you ;)
« Last Edit: November 09, 2019, 11:50 by petetherock »
Please post instead of sending a pm, so more can learn.

My gear:
http://peteswrite.blogspot.com/2019/04/my-setup-42019.html

Offline ronildoq

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #257 on: November 09, 2019, 14:15 »
ok now its time to share, please bear with me, step by step updates coming up... First, lets look at the room noise floor, i couldn't use my laptop as the windows 10 driver wasnt working with REW, until now. so we end up using the MAC book, and i have no idea on how to use it... So, the pictures we took, doesnt show the proper scale , apologies, but if you open up rew and compare you can tell the freq

This is Pete's room noise floor levels. With nothing playing, mic at MLP, RTA was showing noise floor at 35db A, you can see clearly that the peak at 43hz is prominent, 67db (seen on graph right top), >30db with nothing playing, all silent and only aircond turned on in the Room itself. The spikes above 1khz indicates the presence of electrical noise within the equipment chain, can be further improved as well. There is one strange peak at 320hz, not sure what is causing that, technically the room modes should dominate < 255hz, the schroeder freq in that room.



The one below is what i have in my records, what i had measured in my hall after the SMT upgrade previously, the noise floor levels. I believe this is even better now after the recent upgrade to pj, but will just use this for illustration purposes



you can see the difference, the maximum spike is at 40db (vs pete's room 67db, diff of 27db with nothing playing), i have a 33hz room mode in my place, but its not as bad or amplified compared to a square room, the ones above the schroeder freq, can be controlled to lower the noise floor, as you can see in my room, they average below <20db, that is why vocals are crystal clear. No intention to discredit anyone's room, im just sharing whats possible and what can be improved further.
« Last Edit: November 09, 2019, 14:17 by ronildoq »

Offline ronildoq

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #258 on: November 09, 2019, 14:47 »
Next we measured the single JL, since Pete was happy with the very nearfield JL subs right behind MLP, pointed straight to the butt area for the rumble feeling. i didnt want to move the JL subs, in case things dont work out, we can revert to the original state. So here is the response of the first measurement



The above is the freq response of a single JL sub, see the peak and dips, huge swings. The above shows clearly, why the thump in the chest was missing, see the big longkang from 60-80hz, midbasss was basically non-existent. The rumbling is only from 25hz to 18hz, another big hole from 26-40hz. With a single JL sub, a lot of Information was missing! This is not a compromise, this is a sacrifice, a sacrifice of details in order not to feel annoyed with the peak and pressure on the ears. You will see why later, with addition of a second sub, that peak in amplitude will multiply.....

here is the spectrogram, the ringing on 43hz that extends beyond 1ms, at 80db peak



Next we faster put in the psi active trap, to look at how things improve, here is the spectro with psi on at front right corner, clearly improved by 300ms from 800ms to 500ms at 60db levels (in teal) and also 58hz plus was brought down too, including some cleaning at 30hz ++. Clearly one unit of this is insufficient !  :o :o



Not sure how many more bigger tuned traps required to improve this area.... i suspect the entire front right corner should be heavily treated to improve it

Offline ronildoq

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #259 on: November 09, 2019, 15:09 »
Again looking at the issue above, you can see why i was focused on balancing the boat, to place the second sub, to fill in the "gaps" from the single JL. The focus was to ensure the subs are complementing each other, and not fighting for the same freq. So this was relatively simple, we dont have to crawl all over the place. Instead, we played a sine wave using REW tone genarator, to find the location where there was peak spl at 55hz and 65hz.

Just using our mobile phone, WIM was around to help, he moved around (C weighting) with his mobile phone, and we found the location that has highest pressure at these frequencies. They were located at the right back corner. Then came the option for sub, we had to go with the REL, as it was a sealed sub, less of a concern integrating with the JL, Seal design with a seal design.



Voila! we found a sub location that was supplementing each other, where the JL was strong at 38hz, the REL was filling the gaps for 65 & 55hz (that midbass thump area) . These were all done before EQ.

But see again closely, with the boundary gain, that peak at 43hz is 10db more than the subs at neafield, which was free from any boundary gain.

Now see again the single Spectro, REL only subs, again the same problem is there, 43hz! Same as above single JL



Again this area has a massive ringing that extends beyond 1ms, no matter where you place the subwoofers, or EQ, this ringing will always be there, its the traits of a square room. No amount of EQ or placement can solve this . Even with both subs supplementing each other to provide the details for bass, the ringing was never eliminated, that abundance of energy at 43hz cannot dissipate.

Adding another sub, will again amplify this region, that is why, 2 subs are the best in that room. Not more, not less. single sub, a lot of details missing.

So this is why i have been saying from the beginning, we will be going round circles if the problem in the right hand front corner is not fixed. This is where we should fix it

Offline ronildoq

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #260 on: November 09, 2019, 15:10 »
to be continued.... gotta head out.... will resume again tonight at this post here

Offline petetherock

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #261 on: November 10, 2019, 09:49 »
Thanks bro
Appreciate your hard work !
I’m receiving the trap on 18/11
If anyone is keen to listen, pm me cheers
I’m guessing that if I do keep it I’ll need to re cal and measure again ?

Please post instead of sending a pm, so more can learn.

My gear:
http://peteswrite.blogspot.com/2019/04/my-setup-42019.html

Offline ronildoq

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #262 on: November 10, 2019, 10:42 »
Thanks bro
Appreciate your hard work !
I’m receiving the trap on 18/11
If anyone is keen to listen, pm me cheers
I’m guessing that if I do keep it I’ll need to re cal and measure again ?

Lol, yea bro, unfortunately yes, have to re-eq. There is no shortcut

But for now, just place it there and listen first, then before buying that, do measure with the trap on Or fitted, see how much improvement it brings to the setup. 43hz not easy to tame due to wavelength size, the second harmonics and subsequent ones not too bad.

That’s why it’s good to first identify the room problems, especially critical are those frequencies below Schroeder, those frequencies will be dominated by the room. The upper frequencies are not as bad, we can control it with EQ or passive treatment.

Once u fix this, even your dynaudio will sing! Every speaker and sub in that room will benefit

Offline wechnivag

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #263 on: November 10, 2019, 12:49 »
Thanks bro
Appreciate your hard work !
I’m receiving the trap on 18/11
If anyone is keen to listen, pm me cheers
I’m guessing that if I do keep it I’ll need to re cal and measure again ?
The corner sub trap from artnovion? They do money back home trial? Power!

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