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Old 27th October 2019
  #1
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Check out my measurements!

Hey all,

Anyone care to take a look at a couple of different .mdat files?

I have recently treated my room, and it sounds pretty good to me! Wondering if there's anything I'm missing or could improve upon?

I'd like to ask if any one has any recommendation for PHYSICAL hum sounds? My Tascam 388 kicks out quite a bit of hum that is not coming out of the speakers, which has skewed my results by the looks of it.

This is with the Tascam plugged in:

https://www.dropbox.com/s/fucasbozkv...0oct.mdat?dl=0

This is with pretty much the speakers and interface plugged in:

https://www.dropbox.com/s/95sp9h8k3u...GGED.mdat?dl=0

I'd love to solve some of this before I started connecting patch bays etc., although maybe it's something I'll have to live with?

Thanks in advance!
Old 28th October 2019
  #2
Lives for gear
No idea on the 388- you're saying the hum is actually coming from the 388? Not the outputs but it makes noise itself?

The measurements look good- you do still have a longer decay time in the bass- this is pretty normal, getting the decay time at LF down is very difficult. On the ETC, there is a bit of junk in the first couple ms. This could be baffle edge diffraction from the speakers themselves, or desk, gear, screens etc. Otherwise ER's at -25 is quite respectable, but there are some very early reflections or diffractions.

You can see both of those pretty clearly in the spectrogram. Long decay time @ ~44hz, and in particular some ER or more likely early diffractions off of something around 1.3ms from maybe 1k-8k. This should be pretty easy to kill off with some fleece or other extra soft fabric if you can hunt it down. Can you post a pic?

Some sort of tuned trap could also potentially tighten up the decay time at ~44hz...but it's also likely that below that you still have a long decay time too if you ever plan to add a sub.

That all said, there's no reason you shouldn't feel comfortable working in this room as is. If it were my room- the biggest priority I would have would be to get a bit more of a house curve going.
Attached Thumbnails
Check out my measurements!-spec1.jpg   Check out my measurements!-spc-zoomed.jpg  
Old 28th October 2019
  #3
Here for the gear
 

Hey Ryan,

Thanks for taking the time.

Here a few pictures of the room as it currently stands:

https://www.dropbox.com/sh/x5z6mmp71...CwnqRXCPa?dl=0

I was thinking that a couple more bass traps in some corners wouldn't go a miss... might try them!

What's a house curve?

Many thanks,
Old 28th October 2019
  #4
Here for the gear
 

Quote:
Originally Posted by RyanC View Post
No idea on the 388- you're saying the hum is actually coming from the 388? Not the outputs but it makes noise itself?
Yes, I believe so, the unit emits a "hum" when it's powered up. Not sure if that's some thing that it is supposed to do or not, possibly transformer hum? Although it's entirely possible there is something else that's plugged in that contributes to the 100hz and 200hz decay stuff I was seeing on the water fall chart; I'll do some more simplifying of devices plugged in and see if anything else tips it.

Thanks!
Old 28th October 2019
  #5
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One other question; would you think it would be a good idea to engage the 45hz high pass filter on my speakers? Might help with some of the low frequency build up etc.?

Also, I have googled a house curve (google is a friend); what is the best way to apply this kind of this? I supposed I could make use of the various EQ adjustments built into the speakers power amplifier! Incidentally, I have the low shelf down by about -3dB right now.

Thanks again.
Old 29th October 2019
  #6
Lives for gear
Personally, I'd rather have the bass then HPF it because it isn't 'perfect'. I think having a really short decay time in bass is something we should strive for where we can- but I think it's safe to say that a lot of good records have been mixed in rooms worse than yours. There is just a bit more of a need to check bass levels on headphones and other systems etc...

I would use the speakers built in switches as much as possible. This is certainly a personal preference situation. I prefer something as extreme as the harmon curve over flat- but IMO the harmon curve is on the bass heavy side for studio work. The B&K curve is a pretty good starting place. The key is to listen to a lot of reference material and determine a house curve that sounds consistently good to you for your reference material. Also a decent analog rack eq could work, or some people will put it in their daw (just make sure to find a way to play ref material through the same eq)

You can actually load a house curve in REW, and then adjust your speaker settings to what looks flat in REW. If you google it, you can find house curve files for REW that people have created.

https://www.roomeqwizard.com/help/he...ousecurve.html

Looking at your pics, you may try some absorbers on the sides of your desk between the tape machines and cabs. I'm guessing that's where the bulk of the junk there in the first few ms is coming from. Something like a fleece blanket can be enough here ...or maybe rockboard etc covered with dacron. You can probably make up something that you could move out of the way when you need to...
Old 29th October 2019
  #7
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Jens Eklund's Avatar
Quote:
Originally Posted by RyanC View Post
The B&K curve is a pretty good starting place.
I would say the B&K curve is the worst possible start. Here's why:

Are 6-7 feet or 1,94 meter too much distance between Nearfields?

The Titanic, room curves and other GS style OT wanderings

The industries (studio but also cinema sound, but still lagging) are slowly realising the mistakes made; let's not re-introduce them.

... but I guess you know this ...
Old 30th October 2019
  #8
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Quote:
Originally Posted by Jens Eklund View Post
I would say the B&K curve is the worst possible start. Here's why:

Are 6-7 feet or 1,94 meter too much distance between Nearfields?

The Titanic, room curves and other GS style OT wanderings

The industries (studio but also cinema sound, but still lagging) are slowly realising the mistakes made; let's not re-introduce them.

... but I guess you know this ...
Thanks for joining in Jens-

Hmmm, I interpret all of Floyd Tooles work and what he shares with the public at large to be that "flat and smooth" is having the least amount of deviation from whatever curve it is...The "Harman Target Curve" is from Toole and company no?

In my personal direct experience, the main issue here is the bass lift, not the treble tapering. Lots of experimenting here with a bunch of engineers actively working and we always come up with +6 to +8 @20hz tapering down to flat around 100hz, each full range speaker measured separately.

In terms of tapering the treble a little bit, I can agree that's a little more dicey. But at the same time many commercial mixes are bright for my taste, and especially are bright to listen to for full work days. I find ~ -2dB to take the edge off, especially for long days in the studio, but I can concede there is more risk here of overbright mixes and agree that -4 ala B&K is too much. I should have been more clear to say that B&K is, to me, a good place to start the experimenting.

I think it's important to keep in mind that the real 'standard' has been set by hundreds of thousands of records that have been released and listened to by the masses and adopted as a sort of de facto benchmark after each person's lifetime of listening. It is certainly a vague target, but musicians, artists and engineers do have a fairly well established concept of it in their minds.

Regarding speaker design- (you know all this better than me, but for the sake of the OP to understand), designing a speaker in an anechoic environment to be flat on-axis obviously doesn't translate to trying to achieve a flat response in an non-anechoic environment. We should see some degree of boundary loading- which is to say every anechoic-ly flat speaker is completely expected to exhibit a rise in bass response in a real room (which as you know can be quite significant). Also it's much less likely that people are seated on the tweeter axis at home or in a car...

Add in a bunch of bass traps, and as you create a quasi anechoic environment it's reasonable to me for end that users to find a good balance there that suits their work.

Last edited by RyanC; 31st October 2019 at 04:57 AM..
Old 30th October 2019
  #9
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akebrake's Avatar
 

Quote:
Originally Posted by robbi View Post
Although it's entirely possible there is something else that's plugged in that contributes to the 100hz and 200hz decay stuff I was seeing on the water fall chart...
Some hum questions:
As I understand it...

1. The Tascam 388 is a console with a built in analog tape recorder?

2. When powered, it emits an audible hum with everything else switched off including loudspeakers. Can you hear it sitting at the console?

3. Is there a fan or motor running? Built in PSU with a vibrating transformer?

3. This noise is visible in REW Waterfall especially at 100 & 200 Hz as REW is using a microphone in the room. Pic1 (your mdats overlaid)
What kind of measuring mic are you using?


Tip: As hum is not associated with decay but rather continuos noise you can try REW RTA in stead. (No sweep) and check improvements real time.
Just click save whenever you like. (Example pic 2 Not your mdat)

Best
Attached Thumbnails
Check out my measurements!-r-shape-hum.jpg   Check out my measurements!-hum-rta-example.jpg  
Old 31st October 2019
  #10
Here for the gear
 

Thanks for the responses, everyone; certainly some food for thought in there and some extensive and eye opening reading.

Quote:
Originally Posted by akebrake View Post
Some hum questions:
As I understand it...

1. The Tascam 388 is a console with a built in analog tape recorder?

2. When powered, it emits an audible hum with everything else switched off including loudspeakers. Can you hear it sitting at the console?

3. Is there a fan or motor running? Built in PSU with a vibrating transformer?

3. This noise is visible in REW Waterfall especially at 100 & 200 Hz as REW is using a microphone in the room. Pic1 (your mdats overlaid)
What kind of measuring mic are you using?


Tip: As hum is not associated with decay but rather continuos noise you can try REW RTA in stead. (No sweep) and check improvements real time.
Just click save whenever you like. (Example pic 2 Not your mdat)

Best
1. yes, that's correct.

2. yes, the hum is coming from the machine its self and is not manifesting in the speakers (as far as I can tell); there is an appreciable level of hiss at higher speaker and mixer levels.

3. As far as I can tell, the hum is from the PSU. There is a motor that kicks in on the capstan, but only when tape is threaded.

4. I am making use of a Behringer ECM8000 to conduct my measurements.

I'll try the RTA feature of REW and see what that yields.

Many thanks!
Old 1st November 2019
  #11
Lives for gear
 
Jens Eklund's Avatar
Quote:
Originally Posted by RyanC View Post
Thanks for joining in Jens-

Hmmm, I interpret all of Floyd Tooles work and what he shares with the public at large to be that "flat and smooth" is having the least amount of deviation from whatever curve it is...The "Harman Target Curve" is from Toole and company no?

In my personal direct experience, the main issue here is the bass lift, not the treble tapering. Lots of experimenting here with a bunch of engineers actively working and we always come up with +6 to +8 @20hz tapering down to flat around 100hz, each full range speaker measured separately.

In terms of tapering the treble a little bit, I can agree that's a little more dicey. But at the same time many commercial mixes are bright for my taste, and especially are bright to listen to for full work days. I find ~ -2dB to take the edge off, especially for long days in the studio, but I can concede there is more risk here of overbright mixes and agree that -4 ala B&K is too much. I should have been more clear to say that B&K is, to me, a good place to start the experimenting.

I think it's important to keep in mind that the real 'standard' has been set by hundreds of thousands of records that have been released and listened to by the masses and adopted as a sort of de facto benchmark after each person's lifetime of listening. It is certainly a vague target, but musicians, artists and engineers do have a fairly well established concept of it in their minds.

Regarding speaker design- (you know all this better than me, but for the sake of the OP to understand), designing a speaker in an anechoic environment to be flat on-axis obviously doesn't translate to trying to achieve a flat response in an non-anechoic environment. We should see some degree of boundary loading- which is to say every anechoic-ly flat speaker is completely expected to exhibit a rise in bass response in a real room (which as you know can be quite significant). Also it's much less likely that people are seated on the tweeter axis at home or in a car...

Add in a bunch of bass traps, and as you create a quasi anechoic environment it's reasonable to me for end that users to find a good balance there that suits their work.
I´ll try once more to explain what I´m trying to say. I know this is a tad technical and I might not be the best communicator …

First; I´m not against a non-flat target curve. The total opposite is true. When I calibrate our systems in studios, I normally make presets with a bass lift from +3 to +7 dB (sometimes even more if the client requests it). I never do a completely flat preset since no one ever asks for it. Most of my clients prefer the +5 or +7 dB preset.

What I´m trying to say is that in the upper range; since what we hear is dominated by the direct sound (yes, we can actually “hear trough the room” to some extent in the upper range, just like we can gate the impulse response to exclude the room contribution, but only for higher frequencies due to the bandwidth requirement); it make no sense to me to try to match the response to a target curve that is based on the steady state response (the entire or at least a large section of the impulse).

The B&K curve is the result of looking at the steady state response of a number of measurements made in domestic environments. If you where to look at the individual measurements and gate the impulse to include only direct sound; I wouldn’t be surprised at all if most of them would measure more or less flat in the upper range.


Look at the graphs in this post:

The Titanic, room curves and other GS style OT wanderings

Notice how the steady state response is similar to the B&K curve but the gated response (only direct sound) measures flat (again, in the upper range).

In a well treated control room, the difference between a gated response and the steady state response is minimal (in the upper range), so if you where to apply the B&K curve; you would effectively tilt your direct sound in the upper range without knowing what you are doing. Again, not saying that some might prefer this, but I also know that you can get used to pretty much any house curve if you spend some time with it …

So bottom line; use whatever target curve works for you but make sure you know what you´re doing or you might add a tilt to your direct sound unintentionally, and then getting used to it witch might end up being a problem later on when working in other studios with a flat direct sound in the upper range (since this is the standard).


More here:

Acoustics Issue

Acoustics Issue

The Titanic, room curves and other GS style OT wanderings
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