I finally got a mic and used REW to analyze my room. Attached is the freq response for 3 different speakers (Monitor Audio Gold Reference 20, Sonus Faber Electa Amator II, and Sonus Faber Concerto Domus).
They all show similar characteristics - at least the most prominent ones. I did play around with the Amators trying them closer together and more forward in the room, but the major characteristics you see were mostly unchanged.
With this magnitude and number of deviations from a more ideal frequency response curve, am I better off biting the bullet and just doing digital room correction, or can these issues be addressed with room treatments without going crazy and having the room look like Frankenstein’s lab.
Cost is a consideration, but doing it right/better is the most important factor.
If digital room correction is a viable way to address this, what are the best solutions today? My system is largely analog (80’s/90’s Mcintosh preamp/amp, tube phono stage), and streaming isn’t a priority (though I’m not against it).
If the better digital correction solutions come in the form of a streaming HW solution, that’s fine, I’d do that.
Just looking for guidance on the best way to deal with the room, as both serious room treatments and digital EQ room correction are both areas I haven’t delved into before.
Thanks all. If more info is needed, let me know. My room is 11.5’ wide and 15.5’ long with the speakers on the short wall. Backs of speakers are 3-3.5’ off the front wall and they’re at least 2ft from either side wall. Some placement flexibility is there, but not a huge amount.
If I wanted to take time based plots, is that doable using reasonably priced tools, or is that a pro assessment job?
Room EQ Wizard (REW) has a variety of tools for that, and their forums are very helpful. Here’s a starter page.
Let me give you a little more background. For frequency response REW and similar tools (I use OmniMic) gate the signal above the bass. That is, they stop listening a few milliseconds after the impulse start to arrive. This deliberately excludes as much of the room as possible to get the response of the speaker. The sound waves are still busy traveling back and forth around the room for a much longer time period than this.
Our ear/brain mechanism does not hear like a microphone. We don’t stop listening, but integrate the experience of the direct sound and the reflections over time and this fully integrated perspective is what gives us an impression of the tonal balance. Often audiophiles only think this is an imaging problem but there is a very significant effect on the perceived tonal balance.
If you ever hear Fritz speakers at a show, he travels with only a few absorber panels. He knows what he's doing, and that his speakers will sound more full that way. We should all take a lesson.
In a very reflective room where the mid/treble bounces around for too long our hearing tends to exaggerate the mid and treble frequencies, so as a result will sound as if the speakers lack bass. So, a tip I often give which people resist is that adding mid-treble absorbers and diffusors will improve the apparent bass, and none of this is captured by simple frequency response plots.
The other thing these plots fail to capture is how having multiple direct reflections, and / or the absence of the right diffuse sound field ruins the illusion of an audio image.
In the bass things are different. The wavelengths are so long that it’s nearly impossible not to integrate the room, so as a result your frequency measurements are integrated. Speaker builders always face a challenge with this and use a variety of techniques to try to get the real speaker measurements like putting the mic 1/4" in front of the drivers, measuring outside, etc.
While room correction software may do a lot for the bass and maybe even correct for perceived extra mid/treble they cannot stop reflections. That’s why in my mind the two approaches are not equivalent but complementary.
Not bad. I always apply 2) DSP to flatten things out further after 1) room correction. . Then finally a third layer of DSP 3) to adjust to my personal preferences, and roll off any wasteful low end to help out the amp and steer clear of clipping, if needed. That pretty much covers everything. Older ears may be well served by ramping up the high end a bit. A hearing test can help determine. I use Roon for this and may end up with anywhere from 1 or 2 to as many as 7-8 distinct filters per Room, including a single convolution filter for the room correction part. Works great. Sound is fine tuned in the end exactly to my personal liking which is what it’s all about.
Always do what you can to set up the room well to start. Then DSP away towards your own personal sonic bliss. Make good buying decisions to set up and integrate everything well up front then anything is possible with DSP from there.
Here's the freq response curve with my listening position about 5ft/60" into the room, which is at the 1/3 point. Speaker baffles are at 37" from front wall (1/5) and 28" from side wall (1/5).
No toe-in currently.
1/3 smoothing, normalized to 75dB at 1kHz.
If I use +/-3dB as a criterial, there are those two peaks at 35Hz and 95Hz, big dip at 58Hz. Not sure how badly these big peaks are potentially degrading the sound. Besides that, a 4dB peak around 650-900Hz, but the rest of the FR curve is within +/-3dB.
This is sitting further toward the back wall at 51" instead of 60".
The 55-60Hz dip is reduced some, but overall it seems a little less smooth than the 60" FR esp from 200-600Hz. Subjectively, it seemed to me that 51" was a little clearer, but the vocals a little less warm. Not sure if that's consistent with what you'd expect from the FR curves.
Here are the two superimposed on each other. . .
On another forum, some members thought it this was workable and I could just go with this based on where the peaks/dips were, with 60" being optimal.
Finally, here's even further back at 45" (compared against 60" as a benchmark):
Here, the 35Hz peak is increased, the 58Hz dip is pretty dramatically flattened out, but the tradeoff is a dip created at 180Hz.
If I wanted to take time based plots, is that doable using reasonably priced tools, or is that a pro assessment job?
I did move my speakers to the 1/5 position from front and side walls, and LP to 1/3 position from back wall. Seems to have helped some. I’ll post the resulting curves soon.
I do have acoustic panels that I think could work for the mid/high frequencies. Had no idea the FR curve and REW program was incapable of picking those up.
Do you have to spend big $ on something like GIK bass traps, or is there a more cost effective option vs spending $500 per bass trap - that can add up quickly!
Also, off topic, I had tried to send you a private message to ask about speakers as you had commented a fair amount on a particular brand and I wanted to ask your opinion on some things. But I got a weird message about a moderator having to approve my message - not sure it was ever received by you. Just sent another message now to try again.
For the record, room treatments and room correction are not equivalent.
Using a frequency response curve to determine if you need room treatments is only useful in the bass. Above that the microphones won't integrate frequency response measurements over time the way we do. You need time based plots for that.
Now, as for EQ / Room Correction... the best you can usually do without bass traps is to clip peaks. After that you raise the overall level of the bass to taste.
With bass traps that are effective at your problem frequencies you can mitigate both much better.
Point is, for your bass, use the simulator to make sure your speakers and listening location are away from the room modes you are finding. Consider placing bass traps near the areas activated by those modes.
As for the rest of your speakers, leave them alone, but in the mid to treble regions having appropriate mid/treble absorption and diffusion helps greatly with imaging and comfort levels. Also taming reflections (which won't show up in a frequency graph) will make the room sound like you have much more bass.
OP, for a reasonably inexpensive DSP solution with more potential tricks in it's bag of, you might look at a Behringer DEQ2496....everything in a tape loop that you could potentially want and then some. The calibrated mic it uses costs 25$....
I've 2 of the older 8024s' that allow me to 'run flat' in a variety of spaces they've been in without treatments....not perfect, but what is?
Sweetwater for new (free shipping); used might be 'out where, somewhere'...hard to mess up an eq.
Steep learning curve, but you'll learn a lot in the effort....:)
@yyzsantabarbaraThanks for the explanation. I wrote to Mitch and we exchanged a couple of emails.
He referred me to a device that could be inserted into a processor loop and interface with a computer to make it work on all sources, though it was an open question on whether the device would play well with my particular process loop (impedance matching and all).
It would be an over $1100 solution for everything which could be worth it if there were no other ways to address my issues.
But I do think my room is shaping up to be okay after all. And Mitch said if I changed my speakers (which is always possible), the filters would need to be redone, so I need to be sure I’m both settled on my endgame speakers and have remaining issues that keep me from being happy with the sound without DSP.
@captouch Mitch creates a DSP package called a Convolution Filter. He uses some very expensive audio software to do this ($20k). This software is way more powerful than any physical audio gear that is inserted in a processor loop.
As I mentioned before the Convolution Filter is a digital only solution. That is your CD player, and tuners are out of luck. It only works with a DAC.
You install the Convolution filter on a music server, which is a computer. In my case, I use ROON Core on a cheap computer and install the filters on that ROON Core server. ROON has a GUI to install the filters. The filter is in the signal path (not sure if that is bad) and applies the filter BEFORE the bits are sent to the DAC. Your streamer sends the modded bits to your DAC. The DAC is connected to your preamp.
In my opinion the best way to do DSP (but only digital sources)
BTW - what I describe in NOT ROON DSP. The same filter can work on JRiver which is completely different from ROON.
Yes, I'm kind of leaning against considering that the room seems "good enough" now that I've tweaked listening and speaker position.
To do a MiniDSP w/DIRAC Live experiment would be $500 minimum and to do a more sophisticated custom filter would require inserting a computer into my setup to run the more sophisticated DSP - that's $1000 minimum. Either of which would add an ADC/DAC step.
I'd never use dsp on an all analog system, except for subs which is practically a necessity. My experience is all the dsp software I've tried has negatively altered the presentation such that it sounds less 'natural'. Roon dsp atrocious, HQPlayer much better, still, prefer room treatments in my dedicated room.
Bass was a constant issue/problem for me when I had larger (mostly full-range) bass reflex speakers. Switching to still large but somewhat lower range limited (down to 40 Hz) acoustic suspension speakers with dual large’ish subs gave me tremendous flexibility to tame bass response issues and resulted in much better sound across the board.
For you folks implementing active correction, once you do the evaluation, how is the active correction implemented physically? Do you need to run the signal through a DSP device? Doesn’t that add noise? I do not see too much about active correction in these forums but maybe I haven’t been looking.
I personally have found that digital room correction does a lot more than room treatments, but I listen to digital sources primarily and the OP is mainly analog.
Just wanted to update the thread about the results of playing with the listening position based on suggestions from forum members (on another forum).
The suggestion was to follow the rule of odds in speaker and LP placement. This resulted in putting my speakers with front baffles 37" from the front wall (1/5), 28" from side walls (1/5), which placed them roughly 80" apart.
The original suggestion was to have my listening position (LP) 5'/60" from the rear wall. I took a FR measurement there. But this LP moved me pretty far forward from my Atmos centered LP, so I took some additional measurements moving further back toward the back of the room in ~6" increments.
If we zero in on the 55-60Hz dip as a reference point:
The blue (lowest trough) is the 60" off back wall LP
Next higher green line is 52"
Next two higher lines (purple and bolded yellow) are ~46" (I tried to replicate this with a second measurement later, was probably an inch or two off from original position, but it's close)
Highest brown/gold line is the near-original 40" off back wall LP (I think I originally started at 38")
My observation is that the LP doesn't much affect the 35Hz or 95-100Hz peaks - they're pretty much there and similar in magnitude regardless of LP within this range.
The 55-60Hz dip though is pretty heavily influenced by LP with it filling it more the further back the LP moves toward the back wall, but this comes at the expense of creating a new dip at ~180-190Hz, which isn't as deep as the 55-60Hz one, but it's definitely a trade-off.
Based purely on this comparative FR curve, I think I like the bolded 46" off the back wall response the best. It fills in the 55-60Hz dip to within -3dB and keeps the 180-190Hz dip it creates to within -3dB as well.
So if I stick with this, I just live with the -3dB dips and experiment to see if there's anything in the way of reasonably priced room treatments to reduce the 35Hz and 95-100Hz peaks.
Does this seem like the best compromise and an overall "good enough" room environment to not have to spend money on expensive room treatments or digital room correction?
Room treatment is as much about reverb time (Rt) as frequency variations, particularly in frequencies above 100hz. You don't want sound bouncing around your room. Below 100 is a different story. EQ can help there.
Diffusion and absorption can help minimize frequency variations above 100hz as well as get Rt down below 300ms, or about 1/3 second.
Below 100 hz, Speaker placement and subs are the better solution. EQ is most useful below 80hz. Your room is a system like your components. You have to work with various elements to optimize it. REW can help but I find a real time analyzer to be important as well. With a live 1/3 octave display, you can walk around your room with a calibrated Mic and see what's going on. Then you can try different solutions and both measure and more importantly, hear the results.
uhm you should never smooth bass region in REW... so use VAR smoothing. Also you need to tackle the modes. Push your speakers closer to the front wall and see how that changes the RTA and the modes in your room. DSP is used in tandem with treatment, but treatment takes precedence @captouch
@yyzsantabarbara Where does Mitch's DSP insert into my system? I'm using one of either of two preamps: a late 80's/early 90's Mcintosh C35 or an '80's Conrad Johnson PV5.
Typically, I'll have 2-3 analog inputs into the preamp (CD player, DAC, and tube phono stage into C35 or will use built in phono stage when using PV5). Both have processor loops where something could be inserted into the signal chain to work on all inputs, but for Mitch's solution, would this have to be a computer?
@rooze My room is a dedicated room for me, so there’s some flexibility in room treatments -within reason because I still don’t want it to look too wacky. But it also doubles as an Atmos HT room and 2-ch audio room. Because of the way my side and ceiling Atmos speakers are placed, it’s hard to move my listening position by too much without getting me out of the ideal spot for Atmos.
I’m using cheap acoustic panels in the corners (not true bass traps) and have some I can use on the side walls, but looking at REW measurements with and without, I’m not sure they’re doing much.
But I can definitely take more REW measurements with the mic in different places to see if that bass dip does smooth out. It can either give me some incentive to try to find a way to move the LP, or resign myself to the fact that it’s not easily fixed without a sub or room correction.
I do have a SVS sub I use for the Atmos system. With some switch boxes (I have two Schiit Sys devices), I can double up the use of that sub for both Atmos and 2-ch (I know it’s not an ideal sub for audio though).
While I’m using all vintage equipment for my 2-ch setup, both preamps I use (Mcintosh C35 and Conrad Johnson PV5) have processor loop options for a hardware DSP solution.
One thing that would seem to work is the miniDSP Flex device which uses Dirac Live. It’s about $750 (I guess $800-825 with tax/shipping) and I believe you can only selectively treat the frequency ranges you want.
On one hand, it’s not a cheap solution, but bass traps from places like GIK can run $400-500 each too, so I could easily spend as much or more than that on acoustic room treatments.
Contact Mitch Barnett or read his book on DSP (Amazon.com). I got his book and found out it was too complicated to do myself, so I paid Mitch the $750 for his remote DSP service.
If you have DSP done by him, you should not need other physical treatment options. I had both since I had gotten GIK treatments before I contacted Mitch. I gave away my GIK treatments recently and if I ever need treatments again, I will do it digitally using Mitch's analysis.
This does not help with analog sources like my tuners but is not an issue today in my new rooms.
That's actually not a terrible looking frequency response. I'd focus on some room treatments to try and improve bass response. I'd also (if you can) try and move the listening position to see if you can get that dip in bass to smooth out a little. If you've moved the speakers with no noticable affect, then try and move the chair.
You could also look at filling in the hole in the 40-90hz range with a subwoofer. It would be pretty easy to do and you'd hear the benefits.
Since you're mostly analog, I doubt you'd be satisfied with room correction in the long term, unless you can just add correction to the bass frequencies. You don't describe your system in detail so I don't know if that's possible or not.
I've done a lot of experimentation over the years with room correction and I've always ended up removing it.
Try a couple corner bass traps, add a sub, and I think you'll be 95% of the way there.
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