[drummermitchell]

Just installed three Gik T-40's under RT diffusers
Had sent my 28's in for the Blu LEDs so I won't be able to hear what improvements the T-40's will make.
Behind the diffusers i have two monster traps.
OOPs,just noticed,I see some marks on the left side,better bring out the Vac.
So far these are very solid and weigh in at 30lbs.each and make great stands for the above or other trapping.
I'm sure there is plywood on all corners and back.
Can't wait to hear what they can do.

[kiwi_1282001]

Very nice drummermitchell.

I am using GIK's Monster Bass Trap together with some diffusor panels on my rear wall.

Would be interested in your feedback on the performance of the T-40.  Was it really effective in the advertised 30-60Hz range?

[drummermitchell]

That's a nice room,Just go my projector back yesterday(fan replaced)+my 28's haven't come back yet(led change)from green to blue,so I won't be able to know for a few weeks .,I am going to pull out the T40's to hear the before and after.
Now I need a laptop to use for the REW program,Have the mike and pre now.
I did think about those skylines,couldn't afford at the time.

[kiwi_1282001]

Thanks.

Yes, I would really like to see some REW measurements (before and after) showing the T-40's performance.

Cheers.

[50jess]

Very nice drummermitchell.

I am using GIK's Monster Bass Trap together with some diffusor panels on my rear wall.

Would be interested in your feedback on the performance of the T-40.  Was it really effective in the advertised 30-60Hz range?



Do you have pics of the front?

[bpape]

The T40's are 3/4" MDF all around except for the front membrane.  Very solid and no vibration/loss from the cabinet itself.  60 is pushing what the T40's will do.  They're designed to deliberately be more narrow than that.  Figure around 55 as their upper limit.

Bryan

[drummermitchell]

I found that in my small room that the T-40s cleaned up some muddiness on the lower end,
Found my bottom end a lot more tightened up if that's the correct word,no so loose,more slam.
I should be measuring these add ons to see whats going on,soon perhaps as I have aquired my ext pre,mike and laptop(no excuse now).
Plus Gik has the video on their site for REW.

[kiwi_1282001]

Do you have pics of the front?

Here you go 50jess

[kiwi_1282001]

Have changed my rear wall layout somewhat.   2D diffusors now sit on top of GIK Acoustics T38 Scopus bass traps.   Works nicely.   

I have updated my blog with the findings HERE. 

[drummermitchell]

Kiwi,curious as to why the three different types of diffusors.
I assume the diffusive patterns would be all different,wouldn't that give off unorganized patterns.
Perhaps it doesn't matter as I don't know.
Reminds me of using different speakers where none are the same.
Wouldn't it mess things up as far as diffusion,I have searched for answers on this and can't find anything about it.
Thoughts,thx.

[kiwi_1282001]

Hi Drummermitchell,

Thanks for the note.

I must point out that I am not an acoustics expert, so my reply is from my limited knowledge on the topic.   If the reply is wrong - I am sure others will jump in to correct.   

First, the middle panels are not really diffusors.  Behind the wood face is acoustic foam and so the product is mostly a HF absorber.   The perforations in the surface and the surface help to not overdeaden the sound.

Second, yes you are correct - the diffusion pattern on the side wall and rear wall diffusors will be different.   it is prime root 2d diffuser, so every step is different so the diffuse pattern suppose to be different at different incidence angle and direction and even rotating the diffuser on wall will get you a different diffuse pattern.  it is unlike QRD type of 1D diffuser that have the same diffusing pattern on left and right, which can causing periodicity problem when using multi panel.

Third, I believe the different diffuse pattens to be a good thing, because it will diffused sound more naturally.
 

[guf]

Yeah Kiwi I stayed up the other night reading your whole thread! Now i'm telling the girlfriend we have to get rid of all the absorption and get mostly diffusion. Thanks
But really, great read and I appreciate you sharing your experience with us.

[catastrofe]

Found my bottom end a lot more tightened up if that's the correct word,no so loose,more slam.

I love it when you talk dirty...

[drummermitchell]

Yes Kiwi's updates are interesting as nice to read what he's discovered,heck I'm so lazy I bought my laptop,ext pre amp,mic ect and haven't even attempted REW.
I think my room is quite dead that's why I did some diffusors on the back wall.
My whole ceiling (joist cavities) have 10" thick roxull,basstraps in corners and ceiling wall corners
I did play with some EPS diffusors on my sidewalls for speaker first reflections just to see if I would like it.
They sure opened things up and no mudiness,so I'm going to go Gik's Q7D's .
I like RT's video on diffusion that Doug Farrara did in a small room,bass traps in corners,diffusors all around(except first reflections).
Nice to get an idea with the music with and without traps or diffusors.

[kiwi_1282001]

Yeah Kiwi I stayed up the other night reading your whole thread! Now i'm telling the girlfriend we have to get rid of all the absorption and get mostly diffusion. Thanks
But really, great read and I appreciate you sharing your experience with us.

Hi Guf,  I really hope my thread doesn't give the impression that absorption is something that should be ditched.   While it is true I have prefered diffusion in some positions in the room - I still find that striking a balance between absorption and diffusion is important.  What that balance is will depend on many things, not least of which is individual preference.   Too much absorption and the room is dead.   Too much diffusion and the room can be too bright.

A friend of my mine recently made the following statement / observation - that I find quite interesting.  He noted that

"diffusion keeps the sound sustained in the room longer, at a more evenly decay patten and lower amplitude  ...

The human brain need about 30 msec (30/1000 Sec) to make sense of what our ear hear, so by using more diffusion to remain the sound in room at control manner longer , we are hearing more information in the recording.

But acoustic Diffuser have to use wisely, we need to have enough mid high absorber spreading in the room to prevent the too evenly spread mid high affect the tonal balance , making the room become too bright .."   

[DTB300]

......  While it is true I have preferred diffusion in some positions in the room - I still find that striking a balance between absorption and diffusion is important.

+1

[Alex Reynolds]

hile it is true I have prefered diffusion in some positions in the room - I still find that striking a balance between absorption and diffusion is important.  What that balance is will depend on many things, not least of which is individual preference.   Too much absorption and the room is dead.   Too much diffusion and the room can be too bright.

Exactly. I recently wrote an article about decay times that talks about these concepts, and why we perceive some rooms as being "dead" or "live" - anyone interested can check it out at the bottom of our Article page here: http://gikacoustics.com/articles/

[kiwi_1282001]

Hi Drummermitchell,

Interested to know what you finally thought of the GIK T40's?    Are they still in place?

I got GIK to make me some T38's and they were operationalised with good effect.

Please visit my virtual audio system for more details.  (see page 3, post #25).

[drummermitchell]

I actually have them up for sale and going with 24X24 broadband bass traps down below the RT diffusors.

[WireNut]

Awesome room. Love the chair. Who makes it?