First Fuzzmeasure Graph. Any opinions?

[withintheflux]

Hello there folks. I recently moved into a new space and am working on the acoustics of the mix room. I've already done quite a bit of bass trapping. 2 of the 4 corners has floor to ceiling stacked Rock wool triangles and several of the corners are straddled with 703.and/or 702. I've also built a cloud. The rooms dimensions are: (19.3 Ft. wide, 10 Ft high, 15 Ft deep).

I thought that perhaps some of you who have used ET or Fuzzmeasure to dial in your room might have some insight into my own graph. for my test I recorded my left adam a7 nearfield from mix position, with a behringer measurement condenser mic.

Namely, I am wondering how bad or good it looks comparatively. Currently the room translates well, it seems, but I'm just getting aquainted.

thanks!

blake

[bpape]

I've seen a whole lot worse than that. You look relatively good down to about 140Hz. That peak and the one around the mid 50's are modal in nature almost certainly based on the decay plot. The null in between is most likely either positional or potentially a null off the rear wall.

Bryan

[withintheflux]

Thanks Bryan.

The back vertical corners are treated with traps but the wall is bare besides some diffusion. I wonder if I would have luck reducing the two spikes and the null by placing traps against the back wall.

At what point should I accept the room's response? Certainly that is subjective, but I'm curious to know at which point most of you can live with the room's peculiarities. is a 10 db dip acceptable to most when the majjority of the rest of the plot is decent?

thanks!


blake

[foxfyr]

You have a variety of options regarding the 2 prominent LF resonances.

You can simply try employing lots of shotgun corner traps, or you can spend a tiny bit more time to locate the spatial distribution of the ~82 and ~130 resonances and employ tuned (Helmholtz) traps (be they tube, resonant panel, perforated, etc) to more efficiently treat them without killing the remaining semi-diffuse soundfield above the modal window.

The ~82Hz dip bears a bit more investigation, as it can indeed be caused by a room induced reflection or, as it is a common sub/main crossover point, a result of the signal alignment between these two sources, something that a delay unit could help resolve relative to your listening position. Impulse measurements would help you there...as would windowed and convolved ETCs, as you could quickly determine the delta in the arrival time of the two signals and adjust a delay unit accordingly.

As far as above the modal range of 200-300Hz, I would shift your focus to the use of an envelope time curve (ETC) in order to look at the arrival times and intensities of each specular refection(s). Resolving the anomalies from that perspective will resolve the superposition induced frequency anomalies.

[Weasel9992]

Cool. Exactly what measuring tool would you use for that?

"Shotgun corner traps"...you're too much.

Frank

[foxfyr]

Originally Posted by Weasel9992

Exactly what measuring tool would you use for that?

What tool would I use?

I would most likely use either TEF or Easera... But I would not expect anyone to run out and buy them for casual use...

As mentioned earlier, there are many more (affordable) tools such as RPlusD, and perhaps REW (as I have been informed that one can get quite detailed ETC curves from the impulse response without smoothing), that might be used within the scope of what we are referring to here.

From there, Praxis and Smaart (also Mac compatible) would be slightly more expensive, but also more comprehensive options...

[Weasel9992]

Originally Posted by foxfyr

What tool would I use?

I would most likely use either TEF or Easera... But I would not expect anyone to run out and buy them for casual use...

As mentioned earlier, there are many more (affordable) tools such as RPlusD, and perhaps REW (as I have been informed that one can get quite detailed ETC curves from the impulse response without smoothing), that might be used within the scope of what we are referring to here.

From there, Praxis and Smaart (also Mac compatible) would be slightly more expensive, but also more comprehensive options...

Gotcha. I've used SMAART pretty extensively...and I agree with your previous assessment as to the prior purveyor of support for it (ahem). I haven't used it since it changed hands, so I'm glad to hear that. I'm not sure how much that is these days though.

Frank

[DanDan]

Hi Blake, a decent sized room. The response doesn't look too bad. You might get a fuller picture by averaging the responses taken at a couple of spots within your listening area.
Check out the Primer. I have concluded you are best using one speaker at a time for Frequency response, but you can get better Waterfalls by driving both speakers.
With this size room you could probably do better. It often works out best to fire the speakers down the length of the room. Consider that rotation and maybe try moving the speakers temporarily to take a few measurements to see if there is an improvement. Those are small speakers so I would not be afraid to move them close to the front wall, even in your current orientation. Try it and measure. You could get some decent clues as to where the room anomalies are strongest using a room mode calculator. I like the one at www.bobgolds.com and for a more pictorial view hunecke.de | Room Eigenmodes Calculator
Use a fusion of all these tools to get optimum speaker and listening positions.
Full corner traps at the back would certainly help. If you go for the lengthways orientation some diffusion behind might be nice. You could use wood slats for the front of those corner traps. Take a look at John Sayers finishes.
DD
Sound Sound - Homepage

[withintheflux]

I moved my listening position Vertically. I noticed an IMMEDIATE volume increase to the low end. I took another graph.

Looks a bit better to me. Anyone else concur?

[DanDan]

Nice one. This shows the software doing it's job well. An immediate answer regarding the bottom end. Plus some scary stuff at the top. That looks like the sound is arriving at the mic at different times causing comb filtering. I assume you have used the mirror to be sure there are no first reflection points? Fuzzmeasure does ETC and all that other good stuff also, but the mirror is a lot easier! If you are driving both speakers, the sound from the two tweeters will arrive at the mic at different times unless it is perfectly central. I believe only Spock has this final Front Ear..... sorry ;-) I recommend driving only one speaker at a time, then average the results. FM has great averaging facilities. Drive two speakers when investigating the modes.
Historically and I concur there is a wisdom that HF roll off in the CR leads to excellent translation. Bruel and Kjaer and others had suggested curves. e.g. +3dB around 100 falling to -3dB around 10K. See also 'Understanding RTA' at studiotips.com
DD

[Weasel9992]

Yeah...that's really not bad. There's still that thing going on centered around 100Hz and the stuff up higher that Dan pointed out. It's headed in the right direction though.

Frank

[maku]

I've just installed a trial of FuzzMeasure - never used anything like it before.

This room is currently untreated - how bad is it currently? and what would be the recommended first things to fix?

[DanDan]

Maku, you might take a look at the Room Analysis Primer Sticky. It needs updating, so do a search on one speaker or two? I don't think curves such as these tell much without context. One speaker or two? One mic position or an average of many? Software such as Fuzz, REW, and ETF are however extremely useful to show the effect of changes. e.g. move the speakers closer to the wall and measure again.
Room treatment always works wonders. Check out the 'how to' articles at GIK and RealTraps. DIY stuff at studiotips - tips on studio design, acoustics, and wiring. Very simple stuff. BassTrap the Corners extensively, Cloud overhead, and RFZ. Do that and your curve will flatten considerably. I like the downward trend towards HF.
Mixing in a room with such a response tends to translate well to the outside world.
DD

[Weasel9992]

+1 to everything Dan said. Bass trapping will smooth your low end out a good bit. It also looks like you've got some issues in the 1-2Khz region...console bounce maybe? An image of your room would help clear things up.

Frank