Add bookcases and/or diffusion.
Possibly of interest:
https://www.youtube.com/watch?v=HXtsMz5345E&ab_channel=GIKAcoustics
Room Too Dead
Hello All,
I am looking for advice and ideas on how to condition my Home Theater room. I built the theater in my unfinished basement. The foundation walls are covered in insulation and vapor barrier. Instead of construction walls to cover them, I chose a "pipe and drape" to cover the walls. I believe that the room is too dead. It seems to affect overall soundstage in the midrange range. Does anybody have experience with this problem and ideas to add a little "excitement" to the room? Thank you all.
Add bookcases and/or diffusion. Possibly of interest: https://www.youtube.com/watch?v=HXtsMz5345E&ab_channel=GIKAcoustics |
Yeah, those drapes are over-dampening your room. I was in an over-damped room at a dealer once and it was not an enjoyable listen so I know exactly what you’re talking about. I’d try replacing the drapes with thin sheets if they’re much thicker than sheets, or maybe you could take some of the drapes down behind the system and along the sides at first reflection points just for listening. If you’re planning on putting up walls in the future I’d highly recommend reading this by Earl Geddes on how to build a great-sounding room. It’s very approachable and I learned a ton about room acoustics and building materials/techniques — very interesting stuff. Anyway, here’s the link… http://www.gedlee.com/downloads/HT/Home_theater.pdf Hope this helps, and best of luck breathing life back into your room. |
As an experiment try covering sections of the drapes with plastic sheeting or poly tarps. You could even try paper/Xmas wrap (anything that won't absorb much). https://www.tarpsplus.com/products/white-poly-tarps?variant=39757140197538
DeKay |
+1
Thin plastic can reflect highs while still letting bass go through and get absorbed by underlying layers. You’ll need to get it distributed on opposite walls so the sound can bounce around again. By selectively livening up parts of the room you may be able to achieve a desirable effect where immediate early reflections are absorbed but later reflections can stay alive for a while and reach your ears to create some spacious ambience. If you can prevent early reflections from reaching your ears for the first 10 to 15 milliseconds and then have some ambience sustain after that in the room, that should sound really good. That corresponds to a path length of about 14 to 20 feet, so the sound from the first reflection should travel an additional 14 feet to your ear after the direct sound from the speaker arrives. Delayed reflections that cross your head at angles of 60 degrees or more are desirable to create maximum inter-aural difference. Reflections from straight ahead and behind are less useful and should be deflected to the sides of the room. |
Just to be clear, bass will not get “absorbed” in any way whatsoever by underlying layers of drapes — just some mids and highs will be attenuated and that’s it. Bass waves are waaaay too long to be affected at all by some fabric, so they’ll pass right through that uninhibited to your cement walls. |
A heavily damped room is just fine..... IF you can tow your speakers in toward your listening position. When you are dampened everywhere, you lose your reflection and boundries. So, to get a real idea of how well your speakers can throw a soundstage an image, they need to be towed in. If you speakers have natural peaks that are unpleasant, then it gets tough in a room that is highly damped. |
Might as well just listen to a good headphone setup. Same thing and takes the room completely outta the equation and relatively much cheaper.
Yes, there absolutely is such a thing. Nothing at the absolute extreme is ever good. Read this from someone who knows more than you ever will about constructing a great-sounding room and educate yourselves… http://www.gedlee.com/downloads/HT/Home_theater.pdf
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While selecting materials to construct DIY absorbing panels, I found that Knauf (insulation) listed specs on the amount and main frequency of absorption for their products. I selected the right product to tame about 90-100 hz and covered with a gauzy, decorative fabric. . So yes, insulation can absorb lows if it's what the sound reflects from. Poly vs paper vs no batting made differences in the specs. Might look that up, compare to what you're using. The vapor barrier makes it tougher to predict though.. |
I had he same problem as you for years, room is a converted loft over a bungalow. 20' x 20' with no hard surfaces. Sound insulated, thick rubber backed carpet tiles, lots of soft surfaces and no brick walls. It was a really dead space. It all changed for me when I bought my Kef Ref 5 speakers. I think the way the UniQ tweeter distributes a wide dispersion has definitely improved the sound. That forced an upgrade on other equipment and now the quality of the system really does benefit from a dead quiet room. I wouldn't change it. My friends have the opposite problem, trying to dampen down rooms that are far too lively. This is a bigger problem I think. Persevere with your room, when you get it right you will love it. Check out the pics of my room if you like, I don't know how to post an image here - Audiogon don't make that easy!
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When I was researching a Home Theater room, I seam to recall an article about how 2 channel listening is more dependent on a balance bawneen reflections and damping whereas an ideal theater room would be very 'dead'. I believe the concept behind this was largely based on a multi-channel setup. Once you get into 5.1, 5.2.1, or 7.2.1, reflections are more likely to confuse the imaging. For 2 channel systems the soundstage, as you are experiencing, is dependent on the right amount of the right reflections. . That being said,. I agree with others that pipe and drape may be affecting some mid / high frequencies, but you generally need to get int 4" or 6" rockwool before you start dampening the lower frequencies. It could be that these lower frequencies are passing through the drape, the vapor barrier, and getting nulled by the exposed insulation. If you can get some 1/4" Masonite, cut it up into squares, and start moving it around - hanging from the pipes and attached to sections on the studs, and measuring the results - that would be one approach. My 5.2.1 system and my large 2 channel system live in the same space (the horror). I elected to treat it for 2 channel and ignore the 5.2.1 since that's how I use it 98% of the time. |
That’s just mid bass and not what I’d consider “lows.” The worst bass issues typically occur well below 90Hz — think bass guitar, drums, cello, tuba, lower piano registers, etc. Around 100Hz you’re looking at things like the lower regions of the electric guitar, tenor sax, male vocals, etc. that don’t tend to cause major issues in most rooms. Absorptive panels can’t do anything to deal with the lower bass issues that frequently plague listening rooms. |
If you had vintage speakers, they would have brilliance (tweeters) and presence (mid driver) level controls, adjustments would perk the frequencies to your liking. They were made because they might end up in a live room, or a dead room, and your particular preferences. Alas, most modern speakers do not provide level controls I would start, perhaps finish with a multi-band equalizer here's an inexpensive rockville 21 band from Amazon (try it, anything can be returned) (they make a 32 band, but enough is enough) You will learn about your room, specifically what's missing, what boost/cut makes the biggest difference at your listening positions. For home theater, if the equalizer makes the system sound darn good, I would be done. |
Unless experimenting with different methods of controlling your room is part of the fun for you I wound highly recommend consulting an acoustician for the best results There are members here who have spent years trying to dial in their rooms which is something I wouldn’t like to do. Jeff at hdacoustics is very good and his pricing is very reasonable. Good luck! |
I think you may have a complicated issue. It’s not just too dead, it’s got a mid-range suckout. I have heard this in rooms with too many Tube Traps. It happens when the absorbers perform too well in some bands but not as well in others. Your problem may be that you aren’t taking out enough of the high end, so the room sounds too bright, and lacking in midrange only by comparison. You may actually need to add better absorbers in the high end. Diffusors are a good idea, generally speaking. placed behind and directly tot he sides of speakers they can really enhance imaging. One thing you can do is to try to create a quasi diffused pattern by removing some of the curtains you are using, at random intervals, with more removed towards the back than the front. If you have any sort of tone control you can test this by reducing the treble to see if you find hte tonal balance more to your liking. Measurements are good, but IMHO really hard to interpret for this type of issue. |
Hello All, I am overwhelmed with the amazing responses to my question. There is a lot of knowledge here. I tried to upload pictures into the Virtual System last night and encountered a problem with Audiogon. I will attempt again tonight. All of these responses are valid and I hope to begin playing tonight... |
@rick_n That’s a very good thought and gave me an idea — the OP could replace the drapes with plastic shower curtains and even choose a fun theme like underwater with cute little fishies, octopi, seahorsies, etc. all around. How fun would that be? Seriously though, avoiding fabrics that absorb sound seems like, uh, sound advice. |
Or, before going crazy. If it was me before doing anything else, why not just buy a graphic equalizer and make adjustments to increase or decrease the offending eq bands. I am a fan of the reasonably priced Schiit Lokius which I use in my system. Sometimes I just want to add a touch of bass, or a hint more treble. Other times just put it on bypass. |
Mid bass is usually what needs to be gotten after. What you call "lows" are very difficult to absorb. I agree with your earlier statement that curtains and such are not going to absorb much bass or even midbass behind the plastic. Interesting what you said about too many TubeTraps causing mid-range suckout. This is not a situation that I’ve heard brought up before. Are we talking about midrange as below 600Hz? I’ve been told that a good goal for a home listening room is to shoot for an RT60 of about 0.3 seconds in the lower midrange and mid-bass, rising somewhat higher in the bass and upper treble. That sounds like a small amount of midrange suckout. From what I’ve seen of people’s rooms, it’s easy enough to get a rising RT60 in the bass, but getting it to also rise in the upper treble, that’s not something I’ve actually seen yet in a room measurement. My room is currently fairly flat around 0.3 seconds from about 400hz on up, which I consider to be a fairly fortunate result. Most of the time I see the RT60 falling in the treble, with the clarity conversely going up. It’s super easy to absorb the high frequencies. They also don’t tend to get dispersed from the speaker as well. I’ve found a room can sound dead with one set of speakers and not another. The dead-ness I think is caused as much by the average frequency response of the reflections as anything, so a speaker that’s beamy in the midrange and widens quickly in the midbass can make a room sound murky. One that stays wider up to a higher frequency in the midrange can make the whole room sound more lively. I just bought several different waveguides to experiment with. EQing them all flat on axis, the overall effect in the room is strikingly different between them. A beamy tweeter needs to be matched to a well controlled, similarly beamy midbass, which is hard to do. Or you need to absorb a lot of midbass out of the room, and not the highs. |
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Hi @asctim - I really only got to hear this at a show in California where ASC was sponsoring the show. Mamy rooms had tube trabs all over and what I noticed was terrible bass. No matter the gear or the speakers, every system had 1 note that all the bass drums seemed to hit. I don't know if anyone else has used the term "one note bass" but that's really a great description. Better sounding rooms lacked the tube traps but had more traditional, broad band absorbers liberally used. |
Well that’s exactly the opposite of what we would hope to achieve with liberal use of TubeTraps, and not a complaint I’ve heard before concerning TubeTraps. One note bass has been used a lot to describe bass where a particular room mode is dominating. Why a lot of TubeTraps would cause it rather than lessen it is something that requires some deep thought. Was that the 2019 California Audio Show? I was at that show and got to hear several rooms before and after we treated them with TubeTraps. Honestly, I was struggling to notice much of a significant difference. I was new at the time, unfamiliar with the listening spaces, and unfamiliar with the audio equipment, and tired. Most of the rooms we treated were large and I don’t think we were able to put enough treatment in them to get something highly noticeable to happen. The people that were running the rooms felt there was significant improvement, and chose the amount they wanted based somewhat on our own recommendations but also on their ears. Often they wanted even more but we only had so many to offer. In my own experience, one note bass is mostly a speaker placement issue, but can also be addressed successfully with equalizing down peaks. I know some people are dead set against any kind of equalization, so if that’s out of the question, I think a distributed array of subs to break up the major modes is the only workable solution. Or, a very powerful and extensive array of bass absorbers. |
Easily achieve the same effect DIY? I guess that depends on your definition of easy. Dennis recommends very extensive treatments of absorbers that use activated carbon. To do what he suggests is going to take a lot of effort and money. Less money but more effort if you DIY. I got to hear a room he set up last year at the Pacific Audio Show. It sounded good, but there was not much bass because he said he didn’t bring enough subwoofer for the size of the room. He brought a semi-truck load worth of acoustics just to treat a portion of that one room. He basically built a room within a room, building four walls out of bass traps and diffusers. He also intentionally used a mid level Klipsch system with some basic electronics to prove the point that the acoustics could make even a lower end system sound great. On a similar note, at the 2019 California Audio Show we acoustically treated a conference room that had a basic Behringer PA system with an array of TubeTraps all around the room and flanking each speaker. The point of that room was to allow manufacturers to give presentations about their products. Between talks the system would play music. I had several people tell me that room was possibly the best sound at the show! I don't know if I would go that far myself, but it was very nice listening to movements from Swan Lake there. |
Assuming the bass absorbers are relatively broad band that's what I would have expected as well. Sadly my impression was, room after room, all the speakers bass sounded the same, as if they were playing the same song. 🤣 |
Should point out that the Tube Trap experience I had was in multiple rooms of different sizes. It’s also possible the actual problem I had was with additional absorbers in the room. Still, I was mightily unimpressed by all the ASC treatments that show. I don’t remember which show it was but I think Pass was also sponsoring the show, so there were a lot of rooms using Pass electronics that time. That’s another story. :D Without measurement, and using my poor acoustic memory, one possible explanation was a broad suckout of lower midrange. |
All those who are suggesting that the room needs to be lively miss the point completely. The need is to reproduce exactly what is recorded, not what is distorted by room interaction. A dead room does NOT interfere with the signal coming from the speakers. A live room distorts the signals by creating echoes and resonances that change the tonal balance and the sound coming from the driver surfaces.
Using near field speakers and sitting a couple of feet away from the speakers eliminates almost all the room effect. That’s the real beauty of that kind of design.
It's not hard to remove the room from the reproduced music. Just fill the room with artificial ficus trees, 5' to 6' in height. They are excellent diffusers and are inexpensive when compared to "audiophile" room solutions. |
You mean like what you’d hear if you were listening to a band in a room? Oh the horror! Maybe all music venues should be lined with wool so there are no reflections whatsoever. That sounds fun!
Yes, it’s called headphones. If you wanna listen to a high-end audio system the room is part of it and you work with it like it’s a component. Or you can listen in a rubber room. No thanks.
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"Maybe all music venues should be lined with wool so there are no reflections whatsoever. That sounds fun! " If the sound of the original venue is on the recording, then that is part of the performance. But distortion, reflections and/or noise from the listening room should NOT be part of the playback. That's NOT on the recording. The recreation of an orchestra performance includes the venue in which it was recorded. In addition to the musical instruments, I want to hear the symphony halls in Vienna, New York, London, Cleveland, Philadelphia, St. Louis and elsewhere. That does NOT include my listening room.
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@bpoletti Well, I listened to some of my reference recordings in an acoustically dead room on a very good system with Rockport speakers and they sounded lifeless and awful and couldn’t wait to get outta there. Plus, when speaker manufacturers design speakers they don’t do it in acoustically dead rooms (or at least none that I know of do) so they’re not voiced at all for that environment. There are obviously important uses for both absorption and diffusion depending on the room, system, and personal taste, but I doubt there are many here who prefer an acoustically dead room. So I have a different take on this from you, and that’s ok and I respect your reasoning and position — different strokes. The only thing that matters at the end of the day is that we enjoy the sound we get from our systems no matter how we get there. Peace. |
It's OK for you to be wrong. We're used to it. If you like that kind of distortion, so be it. There have been plenty of other "tests" that contradict your comment. In one case, playback of a recording in Powell Hall of a SLSO recording was "wrong" because it excited the hall's acoustics. Played back in a dead room fixed the problem. I know first-hand of the results because I was there.
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@bpoletti So much for “peace.” Well, the vast, vast majority of people here with dedicated listening rooms use some absorption, some diffusion, or some mix thereof to suit their tastes, and of all the threads I’ve read here on treating rooms over many years I don’t remember one person who created or recommended a completely dampened room even though they could — not one. Hmmmm. Suffice it to say you’re in the very extreme minority, so if I’m “wrong” then so are most of the people here, but u do u. Frankly, I don’t think there is a “wrong” here and ultimately, and as usual in audio, it comes down to personal tastes and preferences whatever they be and choosing room treatment is no different. |
I have a room like that downstairs. Acoustically it’s a nightmare. In cases like that smaller is often better. Also you need a lot flexibility in how things get setup. So smaller speakers and separate sub or subs as needed is probably the way to go. Big expensive bulky gear might work but just make life more difficult. Who needs that? Acoustically I would focus on primary reflection points on all surfaces as needed but don’t over do it. |