Control Room response - Analyzing a question for the Pro's

I hope this is the place to bring this up and I really don't want to start a (fight), I just want to post this and ask what you folks thing. First, I am all for designing the perfect mix room and I understand there are some rooms that are better than others, but some of us have to deal with what we have. and that is dealing with different monitor systems Saying that this is my question.. I have a room that was designed and built to spec, my speakers range from Yamaha ns40's, JBL 4412 and a pair of Mackie 824's with the mackie 18" sub. over the years I have worked with 3 room acoustician in setting up the room and looking at the curves, the room looks very good and requires very little in the way of eq. (right now I have white 4400's ) The room as I said use's very little monitor eq's .... Here come the issue. I am thinking of changing out the whites for something like the Ashly protea system, I can drive all 3 pairs and have them all set up through the software... Of course, when folks analyze the room the first thing that everyone tries to achieve is a flat line... (20 -20k, yea right).... but if I recall the last time I had an acoustician come in with their equipment and set the room, both set the room up with a roll off beginning at 8k with a 4db roll of to 16k (per 1/3 octave). I've spoken with other room designers and they say that this is common in the design of the room and it is there to cut fatigue.. (limit ear burn out)... I called about purchasing the eq's and I mentioned that I wanted this curve at the top end and the guy came back on the line and said.. that is the way they use to set the room.. now they tune it flat... So, am I missing something or am I just old fashion? I'd like to hear if others are using this curve in their studio I wish I had the opportunity to design in a great set of monitor speakers, but the ones I have are the ones I have ..... So, let me know would you folks design your room with the curve? I hope I have explained this correctly..

David - I never use EQ on monitor systems - I tried when the craze first started back in the late 70s and had the top line eq like your Whites but it never sounds right IMO. I pulled them out. If you have to eq your monitors your room is wrong, simple as that.

I agree with John: EQ has no place on monitor speakers at all. Apart from the possibility of causing phasing issues (if you don't have phase-linear equalizers), EQ usually only works for one specific location in a room anyway, since you are trying to compensate for room mode issues, and those vary according to your position in the room. Far better to build and treat the room properly to start with, so that no EQ is required. The only time I EQ rooms is when I run live sound in medium size venues, and that's usually more to deal with issues in the signal chain, rather than the room itself. In that case I aim for as flat a response as I can get, and use the console EQ for rolling htings off as required. Even for those venues, I prefer to try to minimize room issues by careful speaker placement, and only EQ as a last resort. But for a studio control room, EQ should never be needed. If it is needed, then there is something wrong with the room, or with the signal chain. - Stuart -

Thanks for the response and I agree, Room Eq's preferably should not be used and I would love for that to be the case. In my previous studio in California and here in this studio in Tennessee once it was built I had 3 independent pro acousticians in to analyze the room like I said in my post. The room is well designed and because of that the eq's just slightly used to address the different speakers. In the room, the two monitor speakers NS40 and JBLs sit in a cavity in the wall on a shelf and not mounted, the cavity is treated as to reduce reflections... the Mackie 824's on are on stands behind my console and the sub is on the floor behind the console. In the photos of the studio on this page http://www.eaglecanyon.com/pages/studiolayout.htm you can see on the front wall there is a storage cabinet, to the left of and right of that cabinet is the NS40's and JBL's and you can see the Mackie's although I have moved them a bit closer the setting here was for the photos. Now, my original question was about rolling the highs off at the top, and the question was because both guys One in Ca., and One in Tn. both said in their rooms that they roll off the top end (they said that in most of the studio's they design did this and it was a 4db drop starting at 8K in 1/3 octaves to 16K where at 16 it would be the 4db down from the 8K. The reason was that "they said" that it helps ear fatigue when mixing long hours. So, for the last two studios I used the white 4400's in the rooms for the Yamaha and the JBL's, (yes, I have 4 white 4400') One one on each speaker. So, again, my original question was are people and studios still doing the roll off on the top end? Why would guys that design some of the largest studio's around tell me this is common if it isn't. I just got SMAART and I am going to set it up and look at my room with and with out the Eq's in, It's easy to do and that will give me a base line, I then can look at the original graphs the guy here in Tennessee ran to see what it looked like 4 years ago... And finally, in my question I stated that a couple of the whites are starting to have an issue in some area's and I wanted to get them cleaned up and checked out.. but, they are out of business, so, that lead me to ask the question of some of the new digital EQ's to replace the whites.... I have had quite a few pro's come in the room, bring projects and listen to them on my set up and all of them think the room sounds great I guess my reason to ask the question I did was to see if anyone else is doing this and if so, what Eq's are they using... But, I"ll check the room out again with SMAART and see what it comes up with and see exactly what the room looks like again with out the EQ's.

I'd be really interested to see the response curves of that room, as well as accurate waterfalls plot of the low end, since I just can't see how it can be that good of a room, based on the photos. Do you have a lot of hidden treatment in there? For example, I don't see any visible bass trapping, first-reflection-point absorption, or front wall treatment, and there seem to be several other issues, such as parallel surfaces, no soffits, etc. I'm really curious about the speakers, too: You say you have them "sitting in a cavity in the wall on a shelf and not mounted"? I guess that's what is behind the grey cloth covers on the front wall? Could you show some photos of how that was accomplished, since it is very likely the source of your equalization issues, given they way you describe it. All of your speakers have fairly flat responses, so should not need any EQ at all. The fact that you perceive the need to EQ them indicates one of three things: 1) The speakers are incorrectly mounted, and you have resonance, comb filtering, phasing, or reflection issues due to the mounting. 2) The room is not correctly designed / built / treated / set up to smooth out the modal response, give you a reflection free zone around the mix position, and treat the remaining issues that any room will have. What ratio is it based on? 3) There is an issue somewhere in your signal chain, from DAW to speaker, causing non-flat response. In all of the three cases, the solution is NOT to put an equalizer in the chain, but rather to fix the underlying issue. Trying to EQ away a problem is like sticking band-aids on a gun shot wound: it hides the "ugly" superficially, but doesn't solve the real problem, and the patient will die anyway. In any event, I've never heard of aiming for anything but flat response in a control room. It's practically impossible to achieve that, of course, but it is the holy grail that everyone shoots for. I can't see ANY reason to roll off either highs or lows on the monitoring system, as all that does is give the engineer a distorted picture of the mix, and his mixes won't translate well. If you roll off highs, your mixes will most likely end up overly bright. I HAVE heard of people rolling off highs in LISTENING rooms, such as home theaters and presentation rooms, and yes I've heard that they do that for ear fatigue, but once again that has no place in a studio control room. You shouldn't ever get ear fatigue in a CR anyway, if you are mixing at 85 dB in a properly set up room with good equipment. My suggestion would be to pull everything out of your final signal chain, going directly from your DAW to the speakers, play calibrated pink noise through your system, one speaker at a time, and measure the room response with a calibrated measurement mic, set exactly at your mix position to start with. Get accurate response curves, and accurate waterfall plots, and post them here, so the experts can take a look at your present room response, see what is wrong with it that is distorting the perception of how the speakers sound, and suggest the correct solutions for fixing your problem. Also draw up an accurate model of your room in SketchUp and post it here, showing the exact shape, dimensions, speaker positions angles and mountings, mix position, doors, windows, existing treatment, etc. Clearly, you have a major problem in your room, and it has been partially disguised with EQ up to now. This is your big chance to fix it properly, and turn it into a truly great room. - Stuart -

David - the rolling off of the high end is a common practice in control rooms, some even go for 6db down at 16khz. But they don't do it with an external eq, they use the roll off built into the speaker. I'm assuming you have the White model which is a third octave graphic eq so it probably doesn't have a high shelf roll off and doing it with graphic eq isn't quite the same. have you tried moving your JBLs out of the cabinet and free standing them? that shelf sound spurious to me - you may have treated the high end reflections but you couldn't have treated the low end.

John and Stuart, Thanks again for getting back to me.... John, thanks for verifying that control rooms do use a roll off at the top end and we can discuss that more latter..... I think the two folks that I spoke with and had look at the room are very familiar with rooms, but those rooms probably use special control room monitors in the walls, mounted correctly and specifically tuned for the room. If I would have had another $20,000 for the in-wall monitors I wanted I probably would not be asking this question.... but I didn't... Stuart, thanks for the response and looking at the photos... unfortunately the photos don't fairly show the design of the room.. I am trying to find the design that I have on a PDF so I can post it, but I"ve been unable to find it today and I have someone coming in at 2pm.. so, I"m running out of time.. There are a number of traps in the room (the bass trap at the rear or the room is about 8' wide by 9 1/2' tall. Like I said, I have just got SMAART and it will take me a day or so to figure how to use it and save the data, I think it will print curves.... I have a measurement mic that seems very accurate (when one of the guys that was analyzing the room was here with his thousands of dollars in equipment I asked him if he could give my mic a try (after he had worked the room with his mic), he was quite surprised at the accuracy. It seems like there is a little difference between Stuart's attempt to achieve a flat response with no roll off and John your comment of using a roll off. This is where my confusion started.... Once I get my SMAART running and set up, It should be somewhat easy to run some graphs and see some differences.. Keep in mind, The JBL's are the lease listened speakers in my room, the Yamaha are proably used 20 - 30% of the time and my Mackie's are probably used the most ... right now, all the speakers are set to as flat as we could get them.. and no room roll off... ( It was in earlier versions of the studio that I had the high end roll off), but the last guy that was in when we were making changes set them to as flat as we could get them.. I have to run but I'll be back with more info and I do appreciate both of you for all the response you have given . Dave

I am reading a different question than what John and Stuart are answering. A big part of the confusion may be beacuse wht is being asked about is not clearly specified. Their are 4 different responses that are connly confused when discussing room response. One is the output of the monitor system on axis, the second is the total power output of the monitors, the third is the repsonse of the room itself and fourth is the combined effect. Current practice is to have a flat response from the monitors, and a roll off on the high end in the room response. The end result is the monitor/room response that rolls off ont eh high end, while having flat response from the initial sounds. I hope this helps, and emphasizes monitor/room system imprtance. Andre

Sigh! Trust André to make it so very clear in a concise number of words! Why can't I write briefly and accurately like that? :( Thanks, André. That's pretty much what I was trying to say: monitors should be flat. - Stuart -

Current practice is to have a flat response from the monitors, and a roll off on the high end in the room response.

I'm sorry Andre - I must disagree with your statement. To roll off the high end via room response means a very dead room that sucks up the highs - I don't like that effect - I've experienced it many times.

John Sayers wrote:

I'm sorry Andre - I must disagree with your statement. To roll off the high end via room response means a very dead room that sucks up the highs - I don't like that effect - I've experienced it many times.

I understand what you are saying (typing? writing?). Excessive roll off is bad. I agree with you. It is something that occurrs naturally because of the reduced Q of monitors at low frequencies. Even flush mounted monitors have a Q of 2 at low frequencies. The phrase room roll off is sonewhat miselading. It is representative of the high end roll off in RT60 shown in AES TD1001. It is not extreme. Thanks for helping to clarify what I meant. Well rolled, Andre

I'm sorry Andre - that's not what I meant - What I meant was what I said - it is common practice, and has been all my 40 years in the business, when calibrating control rooms to roll off the main monitors so they are either -4 or -6db @16khz dependent upon the use - for music it's 4 db whereas for Film it's more like 6. Naturally if you or Stuart have other experience in this I'd like to hear it but its' been standard practice for many years IMO.

John Sayers wrote:

I'm sorry Andre - that's not what I meant - What I meant was what I said - it is common practice, and has been all my 40 years in the business, when calibrating control rooms to roll off the main monitors so they are either -4 or -6db @16khz dependent upon the use - for music it's 4 db whereas for Film it's more like 6.

Sheesh, the multiple standards, and lack of, or evolving, is confusing. Without getting myself into words and sentences that I can understand, much less anyone else, please accept the next paragraph. What you wrtoe John is consistent with my experience of being the best. It is not necesarily a "standard" but it has been recomemnded for years in some circles, and it works great. If someone understands what I am trying to write, please clarify. Loquaciously confused, Andre

What my experience in studios has been (20-something years, mostly in post-production studios for radio and TV, all around South America) monitor response is kept flat, and rooms are not treated with enough absorption, which of course isn't a good combination anyway. The result, as you can imagine, is that mix engineers compensate subconsciously by rolling off their mixes slightly in the high end. For some reason, it works quite well. Mixes that come out of those rooms do seem to translate fine to TV screens in homes: I often hear mixes in progress when I visit my customers' studios, then hear them again a few days later at home, on the TV or radio, and they sound pretty well balanced to my ears. Why that works, I really can't tell you, but it does. I'm only aware of about half a dozen really good rooms in Santiago, which were properly designed and set up by qualified, experienced acousticians (there aren't too many of those around here!), and even in those rooms I haven't seen any roll-off on the monitors. 've seen BASS roll-off a number of times, but never highs. Not that I specifically checked for highs, but I don't recall seeing it. However, I will be sure to do so next time I visit those studios. Maybe it's just a Latin American thing, or maybe it's just a TV / radio thing, assuming that most consumer TV's and radios don't have good high end resposne anyway. I really don't know the reason behind it. Or maybe there ISN'T a reason, except for "we've always done it like that"(!), but that's the way it is here, and curiously it seems to work. Like I said before, I'm aware that roll-off is common for home theaters here (a friend of mine specializes in home theater design and installation), and I usually also end up doing some roll off when I run live sound in small and medium venues, but high roll-off isn't common in Latin American post-production studios in my experience, where "flat" is the way it is done. Maybe Javier can comment on his experience here. From what I recall of his setup, he does not roll of highs on his speakers either (he has both Adam A7s and NS-10s), and his mixes sound pretty good to my ears. But now that there is a doubt here, I reckon it's time for me to do some more research, to satisfy my own curiosity! - Stuart -

Soundman2020 wrote:

But now that there is a doubt here, I reckon it's time for me to do some more research, to satisfy my own curiosity.

One of the difficulties is how the "flat" speaker response is measured. What I am refering to when writing flat monitor response is what is measured by using FFT on initial sound. Response measured with a real time 1/3 octave analyzer would have the roll off John and I agree is good. Just trying to keep the topic confusing. Andre