Tuning the room - dbx driverack questions

Discussion in 'Studio Construction & Acoustics Forum' started by Northeastmusic, Dec 19, 2003.

  1. Hi everyone - I believe this is my first post in the acoustics forum. I have a project studio in my apartment - it's been transformed several times over the last 6 years, and, as such, I seem to have struck a balance between efficient usage of space (not abundant here in Queens) and the results I can get in a small room. My question is, using a device like the dbx DriveRack Studio (which is a speaker switcher/emulator and RTA with GEQ built in to automatically tune the room) - has anyone noticed improvement in how mixes translate to other rooms or systems? I typically mix on my Event 20/20 bas and have small, computer speakers, as a real world alternative as well as a couple boom boxes I check the mixes with. It seems that after tuning the room with this device, the mixes are translating better to most environments. One thing that worries me is that the woofers seem to be pumping a lot more than before the RTA analyzed and tuned the GEQ - so I'm assuming that this is probably a result of the RTA/GEQ trying to compensate for a loss of certain bass frequencies due to room modes (the room is around 11' X 13' X 10'). In addition, I have the typical Auralex foam (bought years ago, don't think I would again) on the walls and a good deal of bass trapping - any thoughts on what might tighten up the sound even more?

    Thanks in advance.

    Steve
  2. lovecow

    lovecow

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    Steve,

    From what I understand, this is supposed to be a mastering tool of sorts. "Get my song to sound like ______________." The overall answer to your question is, to use a tool like this effectively, your room should be effectively treated. If the room is adding "badness," you won't be able to truly evaluate what a tool like this is doing to your music.

    Sorry to hear you won't be coming back. :(

    Regardless, anything you can share about the specifics of your treatments?
  3. Ethan Winer

    Ethan Winer

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    Steve,

    > dbx DriveRack Studio ... RTA with GEQ built in to automatically tune the room <

    Stop right there. :D

    Beware of any device that claims to "tune your room" using EQ or other forms of DSP. It doesn't work, and by definition it cannot work. The most important reason, though there are other reasons too - is because the response changes all over the room. That is, if you EQ the speakers to make the response flat in one location, it may well be very different only two inches away. It would be great if a magic box could replace large, messy bass traps and acoustic treatment. But alas, this is the real world and it just doesn't work that way.

    > One thing that worries me is that the woofers seem to be pumping a lot more than before <

    Yeah, that's one of those pesky "other reasons" DSP cannot solve room acoustic problems.

    --Ethan
  4. "Sorry to hear you won't be coming back."

    Jeff - I guess I should clarify my statement about the auralex foam - I shouldn't have said I WOULDN'T buy it again, but I think I bought more than I needed - a little would have gone a long way. Also, I made the mistake of going with all 2" foam - where some of the thicker stuff would have helped a bit more, especially in my older studio. That being said, I ended up gluing some of the 2" pieces of foam together with foamtak to make some thinker 6" wall panels behind the monitors, because there are glass windows behind them. Do you see any problems with tripling up the foam in this manner?

    I will take some measurements and post the details of this room soon - hopefully later today.

    I thank you both for your opinions thus far.

    Gratefully,

    Steve
  5. lovecow

    lovecow

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    Steve,

    Not at all. In fact, there is one product in particular we offer that is based on this "stacking" concept. We have also offered up suggestions to other customers very similar to what you've done. You shouldn't have any worries!

    Also, on the "EQing the room" thing that Ethan talked about. He is largely correct. The only thing I would add is that some folks have had varying degrees of success EQing out single peaks that are consistent in a wide area around the mix position. THIS IS NOT AN ENDORSEMENT OF EQING ROOM PROBLEMS. However, when:

    a. The room has been treated as much as it can be treated,
    b. A peak is present at one (1) (and only one) frequency that "won't go away,"
    c. Said peak is not restricted to "when I put my head here," (i.e., it is consistent over quite a wide area in and around the mix area) AND
    d. There is access to a high quality, digital, parametric EQ...

    Then and only then, it might be found that 3 to 6 dB of "cut" centered at the offending frequency doesn't hurt too much. By doing this, phase anomalies will be introduced. (Not good.) And it is rare that this technique can actually be employed, but I have heard it in action. For the trained ear, it's obvious, but I can hear how it could be argued that "it's better than nothing." (Of course, I would argue against it, but I also don't think it's absolutely a "black or white" issue.)

    It absolutely does not work the same with dips. One should never, ever attempt to correct a room dip by "boosting." Period. End of story.

    Not to mention that if you have two or more trouble peaks instead of one, forget about it. Treat it with traps, prayers, etc. :)
  6. Ethan Winer

    Ethan Winer

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    Jeff,

    > Then and only then, it might be found that 3 to 6 dB of "cut" centered at the offending frequency doesn't hurt too much. <

    I don't disagree with that. Thanks for clarifying.

    --Ethan
  7. Again, thank you both for responding so far. Here's a quick drawing of my studio - the dimensions are basically fixed, as it is a rented apartment. But if anyone has any ideas on repositioning anything to get a better sound - please do voice whatever opinions you may have.

    I should mention that aside from the foam mentioned in the drawing, the entire room is treated on from the top of the ceiling DOWNWARD 2 feet with auralex 2" foam. Too much? Too little?

    Again, all opinions welcome.

    Here's the drawing:


    [​IMG]
  8. lovecow

    lovecow

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    Steve,

    Room looks pretty good, though I (naturally) have a few comments:

    1. The first thing that jumped out at me was the lack of ceiling treatment. Is there any, or did you leave it out for clarity? If there is none, you might want to consider a plywood (or other thin panel) "cloud" suspended maybe 6" to 12" down from the ceiling. (I am suggesting this for acoustic reasons - below - but also b/c you have the room for it! :)

    3. Finally - and Ethan will probably point this out as well - you might be lacking in treatment along the rear wall. Some broadband absorption or diffusion or mix might come in handy at around ear level. (Of course, if that's an upright piano, you may have a bit of a challenge there.)

    Finally, to answer your question, I don't think the 2" as a "border" around the room is too much. The math is easy - that's about 20% of the walls. Some might say that's just enough. Of course, with your corner "traps" and 6" front absorbers, it should be a pretty alright sounding room as is. It just needs some tweaking.
  9. audiotech

    audiotech Guest

    #1. I must have 20 sets of different monitors. (The Alesis model ones being the 1st to go). We used to run out to the car to test the difference.

    I have relized 6 major factors.
    ONE: I now use the Audix 1-A FLAT Reference monitor.
    They sound great and give me the exact mix.

    TWO: Move the speakers away from the back wall.
    (3 feet if you can). If not foam from the back of the speaker around the nearest corner. (Maby even eliminate the corner 1st)

    THREE: Stay symetrical.
    FOUR: Do not use anytype of rear vented speakers
    They are tooo Room dependent.

    Another alternative is to Broadcast into your car via
    a radio transmitter. People are used to their car speakers and can cell phone you to tell you which way to go.
    I have a radio transmitter kit under construction and it will be forsale come January 04 at artistrecording.com

    FIVE: Never rely on electronics to compensate for your room.
    SIX: Use BeyondMastering.com It is an all analog master that was designed specifically for digital recordings. You will not believe the difference that it will make in your music.(and it costs less than your Drive Rack)
  10. Ethan Winer

    Ethan Winer

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    Steve,

    > Here's a quick drawing of my studio <

    Jeff gave you great advice. All I'll add is you can never have too much bass trapping, so unless you also have the ceiling corners trapped that's another thing to consider.

    --Ethan
  11. Thanks to all who have responded to my post - you've given me some ideas that I'm definitaly going to try and work with. Jeff, could you explain the plywood cloud a little more - I'm not sure I understand what you mean. Is it just a flat "something" suspended down from the ceiling (covering the whole ceiling)? Should it be angled so that the front is lower than the back? Should it be covered with foam as well?

    Thanks again,

    Steve
  12. lovecow

    lovecow

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    Steve,

    The "cloud" idea is nothing new. There are probably some folks here who've done something like this. Maybe even some photos??? (I will scrounge around for some, too.)

    Anyway, when I've done it/spec'd it, it's been to serve the dual purpose of ceiling reflection control and floor-ceiling mode control. To do both, it does need to be rather large, but it does not need to take up the entire ceiling.

    You can start with a 4'x8' sheet of thin plywood. I usually suggest treating the ceiling side with absorption - 2"+ fiber or 4"+ foam. The room side (the side that faces down at you) can be absorption, but with your high ceiling, I think diffusion might be a better choice.

    As for angling, you can indeed tip it so the front is lower than the back, but it's not 100% necessary.

    Also, in your case the 8' dimension should be the width (from left to right). The 4' dimension should be from front to back. I usually like to see about 6" to 12" of overlap with the mix position.

    For a flat panel, you will want about 6" to 12" drop (for the plywood) from the ceiling. For an angled panel, 12" drop at the front and 6" at the back works fine.

    Finally, I realize something like this can wreak havoc with lighting. However, you should be able to mount recessed can lights right in the cloud if you need to.

    Of course, if this is all too much of a pain, you can simply consider some broadband control mounted directly to the ceiling. :)
  13. Jeff - Again, I thank you for your input. I will see what I can do with the cloud idea. The biggest challenge in my particular home studio is, however, not that I am uncapable of the installation, but that my studio, and apartment, is part of a 2-family home. Since my landlord lives below, I have always had to go through great pains to have the studio and attach things to the walls etc. in a manner that, when I finally leave, there will not be a huge repair bill. For example, I've attached all the Auralex foam to 1/4" plywood and screwed the plywood panels into one piece of wood on each wall to minimize the holes that will be left when I leave. It wasn't easy or fast - but I assume that the same can be done with the ceiling to minimize damages.

    Ahh - the pains of living in NYC!!!!

    Again, I thank you for all your help. Perhaps after my return from a well deserved, though short, vacation, I will be able to tackle this obstacle.

    As for the room off to the side in the diagram - you are correct - there is no door. There are wall-mounted book shelves, which pretty much act like diffusors - but I will attempt some absorption there as well. What would you think of installing a "door" that was essentially a swingable partition - perhaps a kitchen entrance type swinging door OR, easier yet, some think blankets hung from the top of the door that act like curtains?


    Thanks in advance.

    Steve
  14. lovecow

    lovecow

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    Steve,

    A 4'x8' sheet of plywood with some treatment on it won't weigh "nothing." However, the right number of small hooks on the ceiling and on the cloud should allow you to hang it without any major damage. I.e., if the thing weighs 30 lbs and you need 5 hanging points minimum, that would be 5 hooks rated at 6 lbs each. If the cloud weighs more, the hooks get bigger. My point is, use 10 (smaller) hooks rated at half the weight. Or 15 rated at 1/3. Etc. Smaller holes means less damage. (But maybe just as much spackle! :) )

    Unless it's a door that closes completely, the lows and mids are still likely to escape through there somewhat. The swinging, kitchen-type doors are a better idea than the curtains/blankets. If you decide on doors, you will have to (ack!) treat them as they will now be a source of early reflections. (Catch-22 if e'er there was.)
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