Tillerman Posted August 7, 2002 Share Posted August 7, 2002 Can anyone point me to information on how room size affects low frequency extension? Thanks, Scott ------------------ Definition of an idiot: Noun; Someone who doesn't know something you learned yesterday. Quote Link to comment Share on other sites More sharing options...
kenratboy Posted August 7, 2002 Share Posted August 7, 2002 Very complex, just buy Bose. Ho, I mean, there are better people to give you answers, just wait a few hours. ------------------ Receiver: Sony STR-DE675 CD player: Sony CDP-CX300 Turntable: Technics SL-J3 with Audio-Technica TR485U Speakers: JBL HLS-610 Subwoofer: JBL 4648A-8 Sub amp: Parts Express 180 watt Center/surrounds: Teac 3-way bookshelfs Yes, it sucks, but better to come. KLIPSCH soon! My computer is better than my stereo! For JBL related subjects and more fun, click: http://www.audioheritage.org Quote Link to comment Share on other sites More sharing options...
Hardhead Posted August 7, 2002 Share Posted August 7, 2002 Scott-- This may be more than you wanted to know, but it's part of an EXCELLENT series of white papers on acoustics: http://www.harman.com/wp/index.jsp?articleId=122 This message has been edited by Hardhead on 08-07-2002 at 10:11 PM Quote Link to comment Share on other sites More sharing options...
jdm56 Posted August 8, 2002 Share Posted August 8, 2002 An excellent book for you is "THE MASTER HANDBOOK OF ACOUSTICS", by F. Alton Everest. ------------------ JDM Quote Link to comment Share on other sites More sharing options...
Klipschguy Posted August 8, 2002 Share Posted August 8, 2002 Okay, I read the whole standing wave article - it was good. On point though - in general (standing waves aside), big rooms need more woofer to provide good bass response when compared to a small room. For example, a church or auditorium will usually have MANY large woofers to provide the good bass response. A large living room may need a couple of 15" woofers (plus a sub in my case). A small bedroom can usually get away with a couple of 6.5" woofers. The itty bitty room between your ear and a headphone diaphragm doesn't need a whole lot of woofer to give good bass. Loud, deep bass outside requires some serious square inches of woofer. I have had my Cornwalls in small rooms and in a huge room (current set up). The big room definitely requires more power to get good bass compared to the smaller rooms. The smaller rooms had a lot more bass reinforcement (incidently, due to standing waves though, I prefer the sound in my big room). Also, I actually had to supplement the mighty Cornwalls with a sub in my large room - two 15's were not quite enough for flat response. Now the bass is deep, powerful and APPROPRIATE TO THE ROOM. Now, if I put my Cornwalls and sub in a huge auditorium, they would be suckin' wind and be woefully inadequate. Woofer area must match the room. Anyway a complex issue. I hope this helps a little. Regards, Andy This message has been edited by Klipschguy on 08-08-2002 at 04:40 PM Quote Link to comment Share on other sites More sharing options...
jdm56 Posted August 9, 2002 Share Posted August 9, 2002 Along with Andy's comments, I would just add that below a rooms lowest resonant frequency, bass performance is a matter of pressurization, and wave physics don't apply. Which explains why you can get all that sub 40hz boom in cars and trucks. And why it can be so hard to get flat, deep bass in a decent sized room. ------------------ JDM Quote Link to comment Share on other sites More sharing options...
Tillerman Posted August 9, 2002 Author Share Posted August 9, 2002 Thanks for the replies. I did read the white paper which was very interesting. However, I still am searching for info. Here is the question: If you have a sub which is capable of < 20 hz reproduction at audible levels, how does room size affect the reproduction of the lowest frequencies, say 15 to 25 hz? Scott ------------------ Definition of an idiot: Noun; Someone who doesn't know something you learned yesterday. Quote Link to comment Share on other sites More sharing options...
Hardhead Posted August 10, 2002 Share Posted August 10, 2002 Scott-- OK, you read the article, but did you see the standing wave calculator? Enter your room dimensions into the program, and it will tell you which frequencies will present problems in your particular room and the precise location of the nulls and peaks of those frequencies in that room. It will also tell you which frequencies will be a particular problem in your room by showing you how they stack up (literally) against other frequencies. You need to have Excel to make it work, though. Somewhere in those white papers it tells you what to do about the standing wave problems that the program has identified, including subwoofer placement to make the worst nulls disappear. The standing wave calculator is pretty interesting, and it gives you a ton of information if you can figure out what it all means. Have fun. Quote Link to comment Share on other sites More sharing options...
Klipschguy Posted August 10, 2002 Share Posted August 10, 2002 You'll have an easier time squeezing 20Hz out of your sub in a small room, but standing waves will likely be more problematic. Put your sub in your listening spot, put on some familiar music with good bass content, then move about the room until the bass sounds best to your ears. Put the sub in that location. Also, if you don't already have one, get a test CD which has test tones they can be quite useful for setting things up. Interestingly, people talk a lot about reproducing 20Hz (and 15Hz for that matter), but when I generate a loud 20Hz test tone so my dB meter is crankin' just shy of 100dB, I don't hear or feel much of anything (except when a loose window frame started rattling). Sounds like a distant, breathy, air disturbance - subtle. When I do the same thing with a 40Hz tone, the low bass is quite audible and shaking the whole couch. I'm may be wrong, but after messing around with low frequency signals and knowing what they sound like, I'll bet if I generated a 90dB pure 15Hz tone (free of higher harmonics)in my room and someone walked in, they wouldn't notice anything. It would be a really interesting experiment. Elephant communicate all the time with sub 20Hz tones -I've never noticed anything when I go to the zoo (whales do the same thing, for that matter). By the way, I'm not knocking full spectrum audio output. I was just a little surprised when I discovered what these tones actually sound like. Also, I do demand that my system be reasonably flat all the way to 20Hz -even if it is hard to hear. Great stuff. Andy Quote Link to comment Share on other sites More sharing options...
jdm56 Posted August 10, 2002 Share Posted August 10, 2002 Yes, below 30hz or so, the sound is not so much heard, as it is felt. And, as far as it relates to music reproduction, I'm not totally convinced that sub-30hz output is worth the cost to produce it well. For HT, I can definitely see the advantage (mechanical sounds, thunder, explosions, etc.), but for music, well, there just isn't that much down there, save for organ and synth, music. After all, the lowest note on a four-string electric bass is just around 40hz! ------------------ JDM Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.