speakers wires connected out of phase, try swaping one speaker connection
What happened to my bass?
Ok, for those of you willing to read a bit, I have, as usual, something driving me nuts. I'm a speaker builder. Current speakers look like Watt/Puppy, consist of 11 inch Eton, 7 inch Scan Speak, Scan Speak Revelator tweeter. They perform very well and I haven't changed anything about them in 5 years.....but I have changed houses and of course rooms. Prior room was twice the size of the current, rather small, living room. Bass was a tad shy in the prior bigger room which was in a basement with a good amount of exposed insulation and floor joists up above. Current room is plaster covered drywall, bass traps in front room corners. Bass is generally quite a bit better in the smaller room and according to my pipe organ tracks, very low bass is no problem. So, finally, to the point. Yesterday I am listening to Bygone Days (Eileen Ivers violin track) and it dawns on me that that track has sounded different in the past. In fact, on second listen, there are bass notes completely missing that I clearly remember. I assume the memory goes back to the prior bigger, bass-shy room! I just don't get it. My sense is that bass is fuller and more balanced in this room on everything else I have listened to, and then I get to this Ivers track and there are bass notes that actually had some growl to them, completely missing? It's really wierd when you anticipate something in music and it has disappeared. Room null? By the way, it makes no difference where I am in the room. I even stuck my head behind the speakers. Am I the only one whose system drives them nuts from time to time?
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I can only recommend that you perform some measurements with proper software, sound card and microphone. (Assuming of course that you actually want to understand what is going on, which is not obvious as most people here on Audiogon prefer to muddle along changing this and that in an endless merry-go-round. Of course each time around the carousel these audiophiles are excited at the new improvement brought about by their latest monthly tweak. And the lack of any rigor in this approach allows them to justify just about any change as an upgrade.) |
Shadorne gives good advice. Measure the frequency response if you can. IMO, it's possible you have a room mode that is resulting in a cancellation at approximately the same frequency as the missing bass notes. It's a little strange that the result is *constant* across the entire room, but I think it's still possible that the explanation is a destructive room mode. If you cannot measure frequency response, the next step might be moving the speakers to new positions around the room, even extreme positions, to see if ANY change of placement can make the undesired effects go away. If you can make them go away with room placement, then you can conclude that it's a speaker/room interaction. If not, at least you've ruled it out. Good luck. Bryon |
Sounds to me like there's some kind of suckout at specific frequencies, which is not at all uncommon, and will vary entirely from room to room. My room has a suckout at around 200hz, clearly visible every time I've done a graph of the room response. FWIW I'd have my doubts that insulation batting had any effect on bass in the previous room, but would defer to other experts to say for sure. And what is "plaster covered drywall"? Do you mean the older style lathe and plaster (which is outstanding for a listening room vs. drywall in a single layer which is not nearly as tight)? |
77jovian, There are several options. Room EQ Wizard (PC) or Fuzzmeasure (MAC) are possible software options. Since you need a microphone and good ones are powered by phantom then you may as well get a E-MU 0202 or some other similar USB box that does A to D and D to A as well as powering a microphone. Finally a microphone and a stand. A cheap but good microphone is the Behringer ECM8000 but there are several other options. I like Fuzzmeasure because it uses frequency sweeps, which has significant advantages in being able to perform more powerful analysis. (Mathematically speaking a frequency sweep can be auto convolved to get a dirac function which is like an impulse response. The only complication of this more powerful analysis technique is you need to know a bit about appropriate 'windowing' so as to ensure you interpret the data properly and do not get hung up on window artifacts - in general the software and help files are easy to follow and their is plenty of information about fourier transforms and spectral analysis on the web) Fuzzmeasure |
To measure room response, I bought a Rives Audio test tones CD and Radio Shack SPL meter. Put the meter on a tripod at ear height where your listening chair is, and measure away. Rives Audio has a lot of resources; check their webpage. It could be a wired out of phase issue, but probably not if it's only specific notes/frequencies. Checking phase won't cost anything but a few minutes of your time, so by all means check that first before buying anything. |
Thanks for responses! And sorry, I have been out most of the day. I'm 99 percent sure it is not a phase issue. I reserve the 1 percent, because I build crossovers and have discovered many ways to make mistakes. So much so, that the first thing I throw in the player is a test CD. I have a dead center image with only the woofer section of the crossover playing and with the full crossover playing. I think the walls are drywall with "thincoat" plaster on the drywall. Looks like they used a sponge to create texture. House built in mid-forties. Shadorne, about 2 months ago, I was considering the room measurement setup described by Ethan Winer on his site. Generates waterfall plots on a PC. Is that your setup does? Up to now I have gotten by with my Radio Shack meter and test tones. I guess things like this bug me so much is that I consider them setbacks. I will try some things tomorrow and I will definately be taking this Cd to some friends houses in the near future. |
Am I the only one whose system drives them nuts from time to time? Absolutely positively you are not! There are so many variables regarding things like impedance matching, current, voltage, the noise floor, the room etc. It's enough to drive an electronics novice crazy. Wouldn't it be great if you could get great music reproduction from high end gear without all the complexity? Sometimes there seems to be no explanation that makes sense to the average person. Frustrates the hell out of me sometimes. I've almost quit a few times. It would be worth it if I could find an audiophile expert, to come in and analyze all these electronics variables in the setup and advise on what needs to be done to maximize what's here or what needs to be replaced!!! I've spun my wheels for sure. |
I hear ya, Foster 9! There have been times that I have looked at something 20 times and saw that it was wrong the 21st time. Crossovers are really bad that way. Brand new cartridges with the stylus mounted way out of whack. Imaging seems to play with my head more than anything else, and really the way some music is mixed it is easy to get frustrated. You have to be very careful selecting music to use as a reference. Luckly I have a couple audiophile friends with younger ears than mine. |
during my speaker searching a couple years back I found that I had one song with a male vocal "grunt/growl/whatever" that was interestingly placed in the freq range such that on some speakers (same room and position) it was diminished quite a lot and on a couple speakers it was just plain gone. Messed around and one of the dealers and I experimented and the only thing we could figure was that something in the crossover was affecting that freq range. Turned out that it was the design of that speaker/xover as several examples did it while the model above and below it in the product range reproduced the tones. Long winded way of asking if you are satisfied that your crossover is OK? |
I posted this on Ethan Winers forum as well. His response: "Yes, it is probably one or more deep nulls". And he also says to measure the room. A good track to test in room bass response is Rebecca Pidgeon Spanish Harlem. The bass line should stay nice and even. If some notes jump out and some disappear then you have a problem. (I found this trick from Bob Katz either from his website or his book on Mastering) |
Results from playing Stereophile Test CD #2 frequency tests and measuring db with a Radio Shack meter, listed as freq/db: 20/64, 25/69, 31/73, 40/76, 50/76, 63/70, 80/72, 100/72, 125/71, 160/72, 200/68. Midrange: 250/62, 315/64, 400/68, 500/74, 630/74, 800/74, 1000/74, 1250/71, 1600/71, 200/72. Treble: 2500/74, 3150/75, 4000/75, 5000/74, 6300/71, 8000/64, 10000/56, 12500/56, 16000/56, 20000/50. Crossover points are 250 and 2500. Not very scientific, but I don't see a reason for missing any bass. |
Paulsax....I'm doing all this critical listening (which might be a bad habit) because I had the idea of upgrading parts on my crossover boards. I even built a second order crossover with slightly different crossover points in case I might have a nice surprise. Well, the second order crossover points of 200Hz and 2000Hz resulted in some sharp treble that was not easy to tame, and less satisfying bass. So the forth-order at 250 and 2500 seems to be a winner. I have to believe that some production speakers might suffer from bad crossover decisions just like hobbyists. See if you can find a song called "call me" by Hans Theessink. Talk about a nice raspy voice. I have it on one of those Burmester CDs. |
I have found larger rooms seem to have more bass , I won't try to argue why this should or should not be , but in the recent past I have had 4 different sound rooms and the bigger ones always seem to produce more bass , and less room related problems . Of coarse room dimentions play a big part too . |
My former, larger room is still what you see when you look at my "system" photos. It was very unusual with all the exposed insulation and floor joists and 2x4 walls. While it was probably a dead room, it also must have been a sound-absorbing room. My bass in that room was definately on the slim side. I am starting to have the opinion that the bass I heard in this track of music, in that room, was probably some anomaly that doesn't happen in my current room. Too bad because the track sounds way better with the bass. I was initially pretty worried that if I was missing something in that piece of music, I must be missing something in general. That really doesn't seem to be true though based on listening and my crude testing. So that CD is going on the back shelf and I say thank you to everyone who chimed in. In time I'll get set up for some better method of measuring response. |
240zracer, you can't have that much absorbing insulation in a room and have a ballance between primary and secondary reflection and refection. It will kill the soundstage and absorb all the highs also. If every other joise would have had drywall on it then the room would have been well ballanced. In my room, as I was experamenting with room treatment, I added two treatments in the corners behind my seating possition and it killed the soundstage. That was with just two wrongly placed treatmens. |
Yeah, it was not ideal. It was the best room I had in that house though. There was insulation to the right only, and a big reflecting window, no insulation up above or in the left wall. I had a wider and deeper soundstage there than I do in this smaller room. I built 6-inch rigid fiberglass bass traps for the front corners, and absorbers for the side walls of my current room last winter. I can't figure how bass traps work with the foil facing into the room, but they definately work. I guess sound waves are pretty good at penetrating things. What kind of treatments did you have behind you? Bass traps or high-freq absorbers? Maybe I can learn how to improve my soundstage somehow. |
