The argument for/against room treatment
- Thread starter MadFloyd
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But wood flooring is better for dancing two-step when i listen to Country and Bluegrass musicI feel strangely conflicted
One should always be free to express himself.
It definitely gives the expression cutting the rug a whole new meaning
I think the idea of comparing recordings of a system playing music in an untreated room vs a treated room is a great idea! I'll see what I can do. In the mean time, way back when somebody made recordings here at ASC of a room playing back the MATT test with various levels of acoustic treatment. It ain't music but you can clearly hear the differences. The following link lets you hear the MATT file direct, and also recorded with various levels of acoustic treatment, including a bare room and a room with a complete TubeTrap system. https://www.acousticsciences.com/sites/walldamp/files/matt_test_tutorial.mp3As I've stated several times, my experience tells me that when a playback system's noise floor is so dramatically lowered its playback presentation will completely overshawdow most/all room acoutic anomalies. I think I've demonstrated that fairly well including sharing a few in-room videos which is my best evidence as words can be so cheap in this audio-only hobby.
In contrast, I also speculated (I don't really know for sure) several times when a playback system's noise floor remains rather high and the playback presentation is significantly compromised. Then that significantly compromised playback presentation most likely must compete head-to-head with perhaps every last room acoustic anomaly (since they cannot be overshadowed). In such circumstances acoustic treatments are perhaps a requirement to make the presentation more tolerable. More importantly, it's a testament to what we have / have not done to improve our playback systems as well as a testament to one's defintions of the term "due diligence". If per some odd chance this is your perspective then I understand and in fact I agree with you.
Also, I stated more than once that because acoustic treatments CANNOT improve our playback systems e.g. the cause, they can only deal with the effects of its playback presentation. That is a fact if I ever heard one in high-end audio. How is it some of you cannot connect some of these dots?
But the proof is in the puddin'. As you can see from some others' comments, in-room videos are beneficial to some and can be rather telling about some things but not quite all things and their value is catching on a little more each day. As far as I'm concerned, there's no reason to take anybody at their word without some evidence to back it up. In fact, far too long this industry has taken others at their word and I suspect that alone is one of the industry's greatest downfalls.
Hopefully nobody's here to intentionally be dogmatic sticks in the mud. You're a smart can-do kinda' guy, right? So why not pony up an in-room video of your own to demonstrate how your acoustic treatments deliver a sufficient level of musicality for your playback presentation? I'm not asking you to like or value in-room videos, nor to believe in in-room videos. It's irrelevant. You don't even need an external mic as at least in my case my smartphone's built-in is actually sufficient enough to convey the message, even if recorded in mono. Sure all these videos require a bit of imagination to listen to just like most playback systems themselves require a bit of imagination to listen to.
Or do you think your word and your logic is sufficient enough in this audio-only hobby? But if you're unable/unwilling to provide an in-room video, then would you please articulate here what you've done to dramatically improve your playback system itself and/or dramatically lower your playback system's much raised noise floor? That won't be near as good as an in-room video but it should still give some of us a much better perspective where you and/or your playback system is coming from.
Rock and Drum videos thread
www.whatsbestforum.com
BTW, based on this and perhaps other links, I'm betting you do get some value from these in-room recordings.
Thank you Tim. That made a pretty convincing case for TubeTraps. I wonder if the sound source was a point in the middle of the room and if the mic was located at a listening seat? Or was the sound projected through an audio system in a listening room with the mic capturing the sound at the listening seat? I'd like to hear a recording of a string quartet in the same room without treatment and then after an experienced set up guy set up the system, and then listen to that compared to the fully treated room.
These tests are interesting, but I wonder how applicable they are to real world conditions. Perhaps very, perhaps not. Hard to say from simply listening to that link.
Good points! We should have photos and descriptions of how everything is setup, the size and shape of the room, the location of the speakers and the recording microphones, and play back the exact same file through the system as the one being offered as a direct comparison. Unfortunately for these old recordings I don't know for sure how things were setup.
F. Toole addresses the subject in his book. Most rugs are very poor floor treatment. In order to have a decent absorption at a reasonable bandwidth we need something like a clipped-pile carpet with porous backing on 40 oz/sq yd (11mm thick) felt underlay.
Even with 11 thick felt underneath a thick carpet, the absorption is only good down to 2000-3000 Hz area.
On its face it sounds like an excellent idea. But why might you think that is an excellent idea? Without care or concern for the quality / resolution of the potential playback system used, isn't that a bit like saying my sports car running on 79 octane fuel performs better after they repave the street? Sure it may run better, but my sports car is still running on 79 octane fuel and all that goes with that.
The same questions apply to acousticsciences.com as above. Then we need to take into account Peter's questions above as well as perhaps another dozen or so questions before any such test tone comparisons have any valid meaning.
Moreover, since acousticsciences.com seemingly sells only acoustic treatments, I'd hardly call this little audio-only tone before / after test objective. Isn't it their hope that potential customers won't give matters much consideration? Besides, with all their supposed high-end audio installations, wouldn't it be clever for them to perform at least one before and after in-room video recordings at least once to demonstrate the improvements for us to watch/listen? Wouldn't that be a far better sales pitch?
I find it rather interesting how those (not saying you) who are so dogmatic about their stance on a given audio subject usually seem to be the same ones unwilling to offer up a recording to demonstrate / substantiate their points.
Is it possible for lower resolution playback systems with acoustic treatments / custom rooms to transport our listening perspectives to somewhere in the recording hall? That's the real argument of this thread, isn't it? Is it possible? Perhaps, but I doubt it as I've yet to hear it actually demonstrated. Yet, I think I'm able to demonstrate by my in-room videos with both superior and inferior recordings routinely that my listening perspective is anywhere but the listening room. If I am, I'm able to do so by ensuring much of the recording's ambient info remains audible at the speaker and secondarily by spending much time with speaker placement and subwoofer tuning. All of which require lot's of work. And if so, then why would I NEED any acoustic treatments for my room since I'm not even listening from there?
Again, the arugment is for/against room acoustic treatments as well as those who are aghast when somebody says they DON'T NEED room acoustic treatements and/or a custom room. IOW, how many times must one fly to the moon to prove it can be done?
If per chance I'm able to demonstrate this routinely, doesn't that imply the NEED is simply folkore? Can I enhance my listening pleasure with the addition of acoustic treatments? Perhaps. Have I or has anybody who ever visited (including reviewers) even once mentioned how the presentation might sound better if only I had room acoustic treatments? I'm still waiting for that one. But again, if, and it is so, my listening perspective has already been transported to somewhere / anywhere in the recording hall, who gives a rat's behind what's being done inside my room? The increased volumes of music info remaining audible at the speaker including volumes and volumes of the recording hall's ambient info have already completely overshadowed perhaps every last listening room acoustic anomaly. IOW, my room is gone.
IMO, acoustic treatments are not much more than a band-aid for potentially bleeding systems unable to keep great percentages of a recording's music info audible at the speaker. Not only does that seem to be what's happening but it seems quite logical too.
The sax starting around the 3:30 min mark should be of particular interest though you may hear a little breakup here or there. Several months ago I upgraded to an iPhone 12 pro and frankly it's been a pain to dial-in compared to my iPhone XR. I'm not quite sure what all Apple did but the iPhone 12 pro's sound fidelity / quality seems inferior to the older iPhone.
Bjorn
Even that graph looks pretty optimistic to me
In real life floor finishes that would go over a thick underlay would have a high flow resistivity and reflect quite a bit as well as being unpredictable
The advantage of carpet if you have a reflective ceiling is that it just calms the room down, reducing high fr reverb
Its been explained to me that our brains deal with floor reflections as normal as we have evolved with the ground under us .. it seems to make sense as reflections fro walls and ceilings seem to be more detrimental than floor when I have employed acoustic absorbers on the floor to see what happened ( they were not practical - just a test)
What are your thoughts on floor reflections
Phil
I have heard that many times too. But it's not my experience from testing this quite a bit. It will depend though.
Firstly it will depend how good control you have over other specular reflections. If there's a lot of specular reflections and especially early ones, the brain is generally not very good at hearing discrete ones. They all sort of drown in a more messy sound. Secondly, it will depend on the directivity of the speakers. But generally most speakers suffers from quite severe floor reflections, resulting not only in comb filtering but also frequency deviations. And strong enough frequency deviations are certainly audible as it changes the overall tonality.
My experience is that it sounds much better with some proper quite broad band floor treatment with traditonal speakers. It sounds smoother with less listening fatigue and I find the depth to be better. For me personally it's very difficult to go back to either a reflective floor or one with rugs after testing better treatment. A rug/carpet basically sucks out the higher frequencies. That's both a step forward and backwards, unlike good treatment.
The very best is obviously to have a speaker that avoids or minimizes floor reflections. Here's a common speaker measured over a reflective floor that measures extremely even anechoic:
I'm showing the graph with high resolution and with 1/12 oct. smoothing to point it out more clearly. While this isn't overall bad, notice the peaks around 900 Hz, around 500 Hz and cancellation between 200-400 Hz. That's mainly the result of floor reflections.
And look at a speaker that more or less avoids the floor reflection and you'll see it doesn't have these issues:
The result is a flatter response due to avoidance of floor reflections and simply better sound.
Here's another speaker design (horn) that greatly minimizes floor reflections in the same room/position and with much the same result (here with a separate "subwoofer"):
This thread got me thinking. I pulled a absorber off my rear wall and moved it to the side wall. Much better. Especially when I pull my speakers out in the room. Then it really shines.
Thanks for the detailed and thoughtful reply Bjorn,
Just so I understand are these measurements done in the same room , and speaker and mic position
Also are they are rectangular window and not time gated - the dips at 50 and 100Hz look like room modes
If it is not too much trouble , pictures of speakers ( at least a similar type) or links would be great
My subjective experience has not been the same as yours - I have moved speakers from a room with absorptive floor at reflection points with some other treatment to a room with polished concrete floor but better treatment for ceiling and wall and the difference was astounding so I concluded ceiling and wall reflections are the bigger issue
Plus we have all heard great sound with no floor treatment
The speakers in the above example are MTM which will have a narrower vertical dispersion so perhaps that supports your position - I have never measured the vertical off axis response ( speakers too heavy to lift)
I agree that all early reflections should correlate with direct sound to the extent that neither absorption or diffusion are ideal and that, at first and second reflections points, reflection away from listener combined with absorption will give the best result - no non corelated early reflections while maintaining a nice reverberant tail in the room
All fascinating stuff - Its amazing how acoustics has moved forward in the last 10 years or so
Cheers
Phil
Taking about floor reflections, i put my speakers on 9" tall blocks to get the horn near ear height. The gain in bass impact was astounding. I don't know if it was the bass rising up, or the speaker being decoupled from the floor. Either reason, I never touched that portion of the setup again.
Earlier I missed Peter's point about having the untreated room set up by an expert, with the notion that perhaps the arrangement alone can adequately negate any undesirable effect on the sound caused by the room. I'm absolutely certain that this can be done to some people's satisfaction in at least some rooms. I'm certain also that we could still easily measure with instruments the effects the room was having on the sound at the listening position, and that the average person could easily hear those effects. By placing acoustic treatments we could change the sound at the listening position in a way that is easily audible and measurable, with the measured result looking more similar to the original input signal. From experience I can say that a lot of people will prefer that change. Bass lingers in most untreated rooms regardless of how perfectly clean and fast the speaker plays the bass, even when the speakers and listening position are as optimized as possible.
I'll try to go with your sports car analogy. Most cars are specifically designed to work on roads that are paved to a certain degree of smoothness. Some are made to handle more roughness with certain compromises in aerodynamics and handling. If we play with this analogy we can ask ourselves what kind of a room is like a smooth paved road and which is like a potholed and rutted dirt road? What is the equivalent to the expert room setup?
First I'll suggest that the expert room setup is like choosing your line while driving. Where on the road can I position this car so that it's going to take the best possible path? We'll assume that this road is repetitive in it's surface features so that you can meaningfully choose a single line and stick with it.
Next I'll suggest that an anechoic chamber is like a glassy smooth, perfectly flat road. Any roughness you feel in the vehicle and any impediment to forward motion would not b the road surface's fault in this case. Choosing your line wouldn't matter. All lines are perfect. A road like this will be highly revealing of the car's characteristics. If the car starts to shake and vibrate badly as it speeds up, you know it's something to do with the car and not the road or the line you chose.
I'll say a reverb chamber would be equivalent to super rough off road course, where you can't even reach 5 mph without being shaken and jostled around considerably. It doesn't matter much what line you choose - they're all horrible. The only thing you can do is slow way down - reduce power. That would be equivalent to turning the volume way down and getting right up close to the speakers. I've never been in a reverb chamber. My boss has. There used to be one under the concert hall at University of Oregon and he did many experiments in there. The slightest sound just lingers on and on in a horrible cacoughney. Fortunately your own body provides some absorption or it would even be worse.
Obviously speakers aren't intended to be played in anechoic chambers or reverb chambers. I think it's safe to say though that listening in the reverb chamber would be the more difficult and unpleasant experience. We'd probably end up sitting with a speaker right next to each ear - essentially turning them into big headphones to get rid of the obnoxious room sound. The reverb chamber could be made tolerable by adding enough furnishings and acoustic treatments. What you would notice though is that getting the reverb down on the treble frequencies with basic furnishings would happen quickly and easily. But the reverb in the bass would still be a problem. It takes some targeting of absorptive properties that most furnishings don't provide to get that bass under control. Going back to the road idea, the rough road would now have it's smaller pits and bumps smoothed out, but the bigger ones would still be there. You can go faster now without vibrating your teeth out but the big bumps and ramps will still throw you out of control if you go too fast.
My depiction is suggesting that the more capable your system is of filling a room with powerful, accurate sound, the more acoustic treatments will matter. I feel confident that it's true. If you are right up close to some small speakers that are playing quietly, the room acoustics won't matter as much. Also, if your audio system has a lot of self noise and distortion, the acoustics won't be able to compensate for that. If your system is capable of filling a room powerfully and smoothly with very low noise floor and distortion, the acoustics will allow the system's good qualities to be more evident.
How bad does a system have to be to not potentially benefit from room acoustics? I'd say considerably worse than anybody's system who's on this forum. How rough and awful does a car have to run before you can't even tell that you've driven over a pothole?
Tim, what happens to your car and road analogy when you’re clear view of the road starts getting obscured fight direct sunlight or fog or the bright and shady effects of driving On a tree line the street with the sun angled from the side?
in my experience, some room treatments remove or alter the otherwise good information coming out of the speaker.
I’m not sure car analogies are there convincing.
in my experience, some room treatments remove or alter the otherwise good information coming out of the speaker.
I’m not sure car analogies are there convincing.
Interesting - I wonder if that extra height allows a clearer benefit of having and MTM arrangement that gives a narrower vertical dispersion pattern hence minimizing floor reflections , sitting on the floor you get a complete mirror reflection and 6 db boost from lower woofer - your new position may be reducing floor reflection cancellation effects
a wild stab in the dark on my part
Phil
I liked the analogy myself. Not so clear is your comment... you have moved from mostly objective features to subjective, and changed from the aural to visual. Just because your vision is obstructed would have zero impact on the road surface or the cars performance. What aural property are you making analogous to filtered sunlight, or fog?
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