Author Topic: Setting up a HT Den in a square room: Compressive Feeling In My Ear  (Read 9149 times)

Offline ronildoq

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #240 on: November 07, 2019, 13:47 »
Hey Bryan
Why point the woofer against the wall


By now u would have realized that nearfield is not as pleasant as farfield subs. You can still sense that energy at one corner.

thats why its best to have the same subs, same size, one each at left and right , or either back front, or left right diagonal. When the subs are split up Left and right location, its very hard to localise the energy, even at higher freq,  the direction of pressure in the room will be spread evenly throughout and equal. Personally i didnt touch the JL Very nearfield subs, as i figured if you didnt like the addition of REL, you can revert to previous single JL. If i were to do it, i will have the JL at front left corner, another JL at Back right corner. both drivers facing wall and facing the trihedral section of it. Then i will work with a trap to kill the standing waves on right front corner

Thats why i mentioned above, the issue is the room, if u move it to front right, and front left, then u can achieve this balance, but you will have extreme amplified SPLs for a given peak and an extreme amplified Null that follows, so imagine if your peak is 10db at 43hz, that will be amplified to 20db (lucky because your height is not 4m. if it is, it will be 30db, then the longkang will be 60db difference), then Nulls are amplified by the same amount, -20db, all in the tonal balance at this range will be off by 40db! Peak 20db + Null -20db

im been advising from the beginning, the issue is the room dimension. Not so straight forward with just sub placement or EQ to solve it. Will have to make do with sacrifices.

Unless u use tuned trap, psi active trap, alter dimension of room. There is no other way. So what you can really improve on in that room is, solve the right front corner area. If you go the passive trap route, u will require probably huge massive panels. that is also provided it is effective with absorption down low 40hz

The reason why i have pointed the REL to face the wall is because this will smoothen out the midbass, using the reflections from the corner to send a single impulse to prevent a muddy midbass.

Ill share the data soon on why this is the case. finally got my laptop working....
« Last Edit: November 07, 2019, 13:49 by ronildoq »

Offline ronildoq

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #241 on: November 07, 2019, 14:00 »
Just to share what I did with REW and miniDsp. All Guru, please correct me if I am wrong.



Audyessy should align the subs and speakers.

1) Turn off Audyessy on the AVR<-- Make sure also all processing is off, Multichannel PCM is selected, Distance on all speakers subs set to 0
2) Make sure all the values/filters on the miniDsp have been cleared
3) Measure one subwoofer at a time. <--Make sure measurements are at least 40db above noise floor for it to be meaningful.XO or filters all off as well on the subs
4) Level match the subs. Use the gain for the outputs on the miniDsp to level match the subs <--this part better to gain match if identical subs, else level match and make do
5) Make sure all the subs are in phase. Either use the phase button on the sub or invert function for the outputs on the miniDsp<--Make sure they are having all same polarity, including with your mains and rest of the speakers. A positive polarity yields much better result. I dont phase match nowadays, i time align the subs, it will automatically be in phase.
6) Measure all the subs as one
7) Use the EQ function for miniDsp 2x4 HD from REW<-- Use biquad filters if possible, much better
8) Export the filters from REW to miniDsp
9) Import the filers into the Input PEQ
10) Run Audyessy again<-- placement of mic is critical, 1st most important, subsequent equally important, they should have reasonable distance away from the various measurements, ie 1m minimum away, can be up down left right. make sure nothing blocking the mic, so it can collect data accurately etc

Offline petetherock

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #242 on: November 07, 2019, 14:59 »
I know you guys are the pros here
But IMHO it’s the REL at the right rear
Cos the JL doesn’t cause any pressure - amazing sub
If wasn’t so ex I’ll buy another
Anyway I’m asking for a loaner of a bass trap to try
Will report back cheers
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 #243 on: November 07, 2019, 18:54 »
I know you guys are the pros here
But IMHO it’s the REL at the right rear
Cos the JL doesn’t cause any pressure - amazing sub
If wasn’t so ex I’ll buy another
Anyway I’m asking for a loaner of a bass trap to try
Will report back cheers

The main reason why the JL doesn’t cause any pressure is because it’s located at the centre of the room 2/3 from back, free from any boundary gains. This is the reason why u are not getting the thump and the ear pressure at the same time from the JL. U will come to realise that it’s an “ either Or “ situation

Get a loaner on the tuned traps if u can find, place it exactly at the right front corner, your midbass and upper frequencies will clear up instantly and that pressure will be gone but not the thumping, everything then starts and stops faster with the tuned traps placed at front right corner

If possible use same dual subs same size , u will be a very happy man

Offline wechnivag

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #244 on: November 07, 2019, 23:58 »
I know you guys are the pros here
But IMHO it’s the REL at the right rear
Cos the JL doesn’t cause any pressure - amazing sub
If wasn’t so ex I’ll buy another
Anyway I’m asking for a loaner of a bass trap to try
Will report back cheers
Hi Pete,

Would like to share some info so your  expectations are in the ballpark.  One or two 60cm x 120cm x 15cm deep fiberglass /rockwool etc bass trap is not going to make much reduction in the 44hz peak. Firstly because porous absorbers work on velocity, and the sound wave velocity is zero at the wall, while pressure is max. Porous absorption traps need  to be away from wall, that's why they are more effective straddling corners with air gaps. With good air gap and corner placement, 8x 60x120 traps is a good  start to getting some good results. Especially because 44hz wavelength is 7.8m, the absorption efficiency is very low. But the entire low, mid, upper bass and even midrange range will benefit greatly. Unfortunately, this approach is not an option for most. You are most welcome to visit my setup if you are curious how a no holds barred treatment approach sounds like.

Tuned traps like Gik scopus or artnovion, are pressure based devices, and they do work well at  boundaries. Due to the tuned nature, they have higher absorption efficiency at the target 44hz. But even that, minimal 4x 60x120 sized traps to have some effect.

Artnovion has a chart on their site that shows the expected number of traps for a given dB attenuation of the tuning frequency peak vs room size.

It's the iron law all over again. Size, cost, effectiveness. Pick only 2...

https://www.artnovion.com/product-categories/3-bass-trap/products/390-bass-trap-corner-range

Cheers!

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« Last Edit: November 08, 2019, 00:00 by wechnivag »

Offline petetherock

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #245 on: November 08, 2019, 00:06 »
Thanks bro
I can’t locate that chart?
Any idea how many for my 4.02 w by 3.98 l by 3.08 h room?
Between buying two equal subs - spend 2.5k
Or buying one sub trap 1.7k
It would seem that the sub gives better yield ?
Of course it needs placement, and one may need a few traps.. but we seem to have narrowed it down to a single position at the front right..
Please post instead of sending a pm, so more can learn.

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

Offline Tiktokape

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #246 on: November 08, 2019, 08:20 »
Nobody can exactly advise how many pieces till you try it out yourself - must note one’s preference too. I will put the treatment as essential to resolve the entire issue.

As for subwoofer, it is up to you to decide whether you seek more because you have multiple unmatched subwoofers. Knock those off and bring in the identical unit.

I will take the former if must choose one only.


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Offline ronildoq

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #247 on: November 08, 2019, 08:44 »
Hi Pete
Just to be clear, the second subwoofer will not solve the issue. The second identical sub is to provide the “coherence” and energy distribution throughout the room. Even if u get in another same sub, placed it at corner, midwall, any location, u will still have that 43-44hz issue. We cannot eliminate it’s presence in that room, until we kill off the standing wave at the front right corner. U have good listening skills, u are able to pick up very fast, I need measurement tools to tell me.

If u can get a loaner for timed trapd, 2 of it, you will be able to tell instantly. What improves further as follows

1. Bass will sound fast and tight
2. Bass will sound cleaner
3. Upper frequencies will be clear and less muddied
4. Thumping will be present
5. Sound stage wider

Loan it for two weeks if possible, listen at your place. Return it after 2 weeks. Immediately u will be able to tell what’s missing and whether or not it’s effective . The impact will be significant from the numbers I have seen

No horse run, if u put in that tuned traps and the above doesn’t improve, dinner will be on me ! Lol

Offline ronildoq

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #248 on: November 08, 2019, 08:52 »
By the way, I love that dynaudio speakers of yours! Very nice sounding speakers. The speakers have very good timing response, that’s why it sounds so good.

Even with the issues in the room, it sounded fantastic, smooth and nice, beautiful sound. (Prefer it over my personal monitor audios, anytime)

I can imagine that big smile once the standing waves are eliminated

Offline wechnivag

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #249 on: November 08, 2019, 15:05 »
Thanks bro
I can’t locate that chart?
Any idea how many for my 4.02 w by 3.98 l by 3.08 h room?
Between buying two equal subs - spend 2.5k
Or buying one sub trap 1.7k
It would seem that the sub gives better yield ?
Of course it needs placement, and one may need a few traps.. but we seem to have narrowed it down to a single position at the front right..
The chart is in the image I posted. A bit difficult to read so I included the link too.

Sent from my X9009 using Tapatalk


Offline ronildoq

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #250 on: November 08, 2019, 18:10 »
The other point I forgot to mention to you is that since the fundamental issue is at 43hz,  you will also have to deal with higher harmonics, ie 129Hz problem coming from all your speakers in that room. This is because when u go with a 80hz -100hz crossover from mains and rest of the speakers, they are now all all contributing to the 129hz standing wave in the room. This is not EQ”ed by minidsp. So u gotta check to see if audyssey is doing the job adding a modal filter in this region

A modal filter will improve ringing and control the energy in this region. The more speakers or subs u add, the higher the absorption u will need at the front right corner. So yes, again highly critical for u to fix that area, that should alleviate most of the nasty issues in that room

Offline petetherock

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #251 on: November 08, 2019, 22:54 »
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
Please post instead of sending a pm, so more can learn.

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

Offline petetherock

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #252 on: November 08, 2019, 22:55 »
By the way, I love that dynaudio speakers of yours! Very nice sounding speakers. The speakers have very good timing response, that’s why it sounds so good.

Even with the issues in the room, it sounded fantastic, smooth and nice, beautiful sound. (Prefer it over my personal monitor audios, anytime)

I can imagine that big smile once the standing waves are eliminated
Hope you get poisoned and join the Dyn club... I had MAs before, very good for HT, but the Dynaudios are sweeter and work pretty well with both Denons and Marantz amps..
Please post instead of sending a pm, so more can learn.

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

Offline Boxerfan88

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Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #253 on: November 09, 2019, 07:54 »
I'm trying out the Art Novion Siena W Subtrap standalone which can handle a 43-46Hz wave.

Subscribed. If at all possible, try to take the REW measurement before & after sub trap. Very interested to know the effectiveness.

The two MOABs in my room have limited effect at that very low frequency.



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Offline ronildoq

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Re: Setting up a HT Den in a square room: Compressive Feeling In My Ear
« Reply #254 on: November 09, 2019, 08:11 »
The design looks good, ideal for that corner placement. The best place to put it is exactly at the bottom where the corners meet, or exactly at the TOP.

Looking forward to your feedback to see how effective is the trap down Low frequency 43hz

Best part now is you know the problems in your room, better understand your room now and have ideas on how to overcome it.