Drum Live Room/Rehearsal Room Acoustic Optimization

How to use REW, What is a Bass Trap, a diffuser, the speed of sound, etc.

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EachHit
Posts: 5
Joined: Fri Mar 28, 2014 4:34 pm
Location: Germany / Niedersachsen

Drum Live Room/Rehearsal Room Acoustic Optimization

Post by EachHit »

Hello I am seeking for a advice how to treat a Drumroom/Rehearsal Room for Recording Purpose.

Here are some Photos and Sketches I made to visualize how the Room is looking right now:
Studio Drawing (cm).jpg
The Height of the Room is 240cm

I also made a 3D Model which isn't 100% Accurate. It's mostly to visualize the Room and where everything is placed. Had to use Sweet Home 3 D cause I didn't get the hang of the Programs which were suggested. Of course the Shelf and the Pianos are Diffusors/Drumkits:
Liveroom 3D.jpg
And here are some some real live Photos to show you how the Room is actually used:
Wall 1.jpg
Wall 2.jpg
Wall 3.jpg
Wall 4.jpg
Ceiling 1-3.jpg
Ceiling 2-3.jpg
Ceiling 3-3.jpg
All Walls are made of coated Flakeboard with a thickness of about 10mm. behind that should be some Gypsum/Fermacell which is much thicker. Behind that should be some kind of Insulation (Mineralwool). The Room itself is actually made of 3 overseas container.
The Ceiling is also made of Gypsum/Fermacell but not as thick as the Walls I think.

The Floor is covered with Laminate about 8mm thick which lies of some Foil (it's called Trittschallfolie in German).

The Wall behind the white Drumkit is made of facing brick which is glued onto some Wood. which was then screwed onto the Flakeboard.

The Basstraps are made of something called PET Vlies which is very light and porous. I can make a Photo of the Material if needed.

The red Absorbers are made of Wood (about 15mm thickness) and are 15cm deep. Completely filled with Acoustic Foam (Hannotect). They also have a closed Back which is made of a thin HDF Board.

I also tried to make a Measurment with REW but I am not sure if I did it correctly. I could deliver the REW File but I am not sure how to upload it.

I hope everthing I posted is not to confusing. As you see in my Profile I am from Germany and it's kinda hard to describe everything in English.

Let me try to wrap up what I am actually going to achieve.

I would like to have some advice on what to do to make the Room better soundwise. Before we had the Facing Brick Wall and the Big Diffusors we had a lot of the Absorbers in the Room and also some of the Skyline Diffusors. I made a few recordings in that Room but for me personally it sounded much too Dead and liveless and of course a little Muddy.
After I removed all Absorbers and only put up the Brick Wall and some Absorbers it sounded much better to me. Of Course the Decay Time is pretty long right now which is something I would like to change.

So here is my actual question: How can I make the Room sound as balanced as possible.

Regarding the Budget. We haven't set a Limit right now. We have about 20 of the RPG Skyline Diffusor. And I think I have foam to build 4-5m² of Absorbers with a Thickness of 15cm. The actual Foam is about 5cm Thick and we stacked them.

Thanks in Advance for everybody who is willing to offer some help. And let me know if I can provide some more specific Information about the Room etc.

Best Regards
Sven
RAD
Posts: 9
Joined: Wed Sep 28, 2016 1:28 pm
Location: San Jose Calif

Re: Drum Live Room/Rehearsal Room Acoustic Optimization

Post by RAD »

Increasing the number of bass traps will improve significantly the decay times and low frequency response...you have about 10% of the volume of the room in bass traps.It needs to be about 40% to 50%.The bass trap in the ceiling should extend the entire length of the wall in both directions...that same construction should be duplicated on as many ceiling/wall corners as possible.

RAD
Soundman2020
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Re: Drum Live Room/Rehearsal Room Acoustic Optimization

Post by Soundman2020 »

Increasing the number of bass traps will improve significantly the decay times and low frequency response...
It will improve the decay times for the low end, yes, but it will also trash the decay times for the mids and highs, unless precautions are taken to prevent that. And it will NOT do much for the frequency response: that's not something that bass traps can fix very well.
10% of the volume of the room in bass traps.It needs to be about 40% to 50%.
Are you really suggesting that the OP should use 48 CUBIC METERS of bass trapping in that room :shock: :roll: One thousand seven hundred cubic feet???? :!: Seriously? That's one entire shipping container full of porous absorption, plus a quarter of another one! I have NEVER seen a room that requires anything like that much! Where did you get such a huge figure from? He would have to make it over one meter thick on every wall, and the ceiling!!! If he did that, the room would be extremely dead: approaching the decay times of an anechoic chamber. No use at all as a studio. There would not even be enough room left in there to put the drum kits, nor to even stand up!!!!

This is a LIVE room, the OP wants to track drums in there: the decay times need to be decently long, but controlled: they should NOT be short. Maybe you mixed up your percentages, and meant to type something else_
The bass trap in the ceiling should extend the entire length of the wall in both directions...that same construction should be duplicated on as many ceiling/wall corners as possible.
Once again, this is a live room, not a control room. There is no need for extreme bass trapping.

The OP already explained that he tried with lots of porous absorption (but nowhere near as much as you are suggesting), and it made the room too dead.

The room needs tuning, not killing.


- Stuart -
EachHit
Posts: 5
Joined: Fri Mar 28, 2014 4:34 pm
Location: Germany / Niedersachsen

Re: Drum Live Room/Rehearsal Room Acoustic Optimization

Post by EachHit »

Thanks Guys for the Answers,

I spend a little time over the last Week doing some recording and having a look at the REW Waterfall Diagram. maybe someone can help me out reading it correctly. Or perhaps helping me out to make a correct Measurment. I would by a good SPL Meter but I am not sure which one to get here in Germany. The One from Soundman2020 sticky REW thread aren't available here in Germany.

I would gladly upload my REW File if i know where to upload it so everybody can have a look at it.

For the start here is a screenshot:
REW Waterfall.jpg
I made the measurment with one of my Yamaha HS50M Loudspeakers. I placed it on my Drum Throne (The Pearl Kit) and put the Microphone halfway in betwee the two Drumkits.
Maybe someone can tell me if the Measurment looks kinda correct.

For me the Data looks like I have way too much Stuff around 300Hz. Which I guess is the Dead/Muddy Sound I hear. On my last Mix of a Recorded Drumkit I pulled out a few db in that Area and did a Highshelf Boost all the Way up from 1kHz. And that sounded much better in my Ears.

Maybe someone could explain to me why everybody is always suggesting a lot of Bass Trapping and Dampening. Isn't that bad for a REAL Liveroom? With every Broadbandabsorber I am killing way more High Frequency's without affecting the "Bad" One's at around 300Hz. Maybe that's why I never understand all the Theory.

Heavy Greetz
Sven
Soundman2020
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Re: Drum Live Room/Rehearsal Room Acoustic Optimization

Post by Soundman2020 »

I spend a little time over the last Week doing some recording and having a look at the REW Waterfall Diagram. maybe someone can help me out reading it correctly. Or perhaps helping me out to make a correct Measurment
The scale of that image means that there's not much detail at all to go on, but even so it is very clear that you have some pretty major issues in the lows, and also in the lower mid-range. I'd need the actual MDAT file in order to be able to analyze it in more detail.
I would by a good SPL Meter but I am not sure which one to get here in Germany. The One from Soundman2020 sticky REW thread aren't available here in Germany.
Any good quality sound level meter will work OK. Make sure it has both "A" and "C" weighting, and also both "Slow" and "Fast" response. A good one will cost you about US$ 100, or equivalent. Avoid the cheap Chinese junk ones that sell for under US$ 50.
I would gladly upload my REW File if i know where to upload it so everybody can have a look at it.
E-mail it to me. I sent you my e-mail address by PM.
I made the measurment with one of my Yamaha HS50M Loudspeakers. I placed it on my Drum Throne (The Pearl Kit) and put the Microphone halfway in betwee the two Drumkits.
That's a reasonable setup for getting a rough indication. So yes, the data is valid, and useful.
Maybe someone can tell me if the Measurment looks kinda correct.
It looks correct, in the sense that it is what I would expect from such a room, but it is NOT correct for how your room SHOULD be when properly treated; in the sense that it does not show a happy room with wonderful acoustics! :) (But you already knew that....)
For me the Data looks like I have way too much Stuff around 300Hz. Which I guess is the Dead/Muddy Sound I hear.
There's definitely bad stuff going in in the entire low and low-mid range (up to about 400 Hz), but that's only part of the "muddy" sound. Likely that is due to other issues, such as over-treatment of the high end. But I'd need to see the MDAT to have a better idea.
On my last Mix of a Recorded Drumkit I pulled out a few db in that Area and did a Highshelf Boost all the Way up from 1kHz. And that sounded much better in my Ears.
Right! The "boost upwards from 1 k" is the key point here: "muddy" isn't just too much bass: it is also lack of high end. There are many reasons why that could be happening.
Maybe someone could explain to me why everybody is always suggesting a lot of Bass Trapping and Dampening.
That's usually more for control rooms, but many live rooms also do need bass trapping, if there are serious modal issues that are distorting the overall response. However, live rooms usually need a lot less bass trapping than a control room does, and it needs to be carefully targeted to only absorb in the actual problem frequency ranges. Typical bass traps absorb across the entire spectrum, but that's not good for a live room, since it kills the high end "sparkle" and "air". So the bass traps need to be modified such that they do NOT take out the high end as well.
Isn't that bad for a REAL Liveroom? With every Broadbandabsorber I am killing way more High Frequency's without affecting the "Bad" One's at around 300Hz.
Yes, you are absolutely right, and you have found this out for yourself: you put in a lot of pure absorber, and got lousy results. What your room needs is target bass trapping, that is tuned to only deal with the problems, while NOT affecting the rest of the spectrum. That sounds easy, but it actually isn't so easy! You would need to do many other tests with REW, with the mic and speakers set up in various locations, to determine what the full extent of the problems is, then design treatment to go in specific places to deal with ONLY those problems.

Perhaps the largest issue in your room is the low ceiling, and that is always hard to deal with. But the good news is that it should be possible to greatly improve your room, so that you can get good recordings on there, and have it sound nice for rehearsal.


- Stuart -
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