[milkpowder]

I have a few issues:

A I was just playing some Stereophile Editor's Choice test tracks and TelArc Surround Test CD stereo setup tracks on my stereo at home. What I tried was playing discreet decay frequencies from around (iirc) 2kHz down to 25Hz. I found that the response isn't smooth at all. For example, 40Hz would be massive, then there would be literally nothing on the 35Hz step, then some resonance at 32Hz. It happens higher up in the frequency range too. How do I smooth out the frequency response?

My uncle told me that there are three dimensions which should not be simple multiples of each other, otherwise some of the bass frequencies may be cancelled out: 1. height of speakers, 2. distance from back wall, 3. distance from side wall. In my case, the height of the speakers is almost exactly half the distance from the side wall on the LHS. Might this be the culprit?

B I played some wide-band discrete frequency tone sweeps through the stereo and apparently if the room was perfectly set up, the sound from all frequencies would only appear to be coming from a single point in between the speakers. What I found was that the image shifted from left to right depending on the frequency. Apparently, this is due to a poorly set up room. Solutions?

C Another thing I tried was to do continuous and discreet wide-band frequency pans, which is basically playing a single tone across the lateral aspect from left to right either continuously or discreetly. The width of the soundstage is massive with the actual sound appearing to come from outside the speakers both on the left and right hand side. I was impressed. However, I would like more soundstage depth and also for the speakers to acoustically disappear. How would I achieve this?

D I have floorstanding speakers where the bass drivers are mounted on either side of each other, close to the ground. Now my components are also placed on the ground, in between the speakers. This means that the right hand woofer of the LHS speaker and the left hand woofer of the RHS will sort of firing into the components. According to the official literature, the two woofers operate in a push-push configuration. Regardless of what that actually means (please enlighten me!), the two woofers have been designed to work together and any slight asymmetry in woofer load (due to the reflections off the components coming back to the drivers) is likely to affect overall performance. In which case, would it be better to put the components elsewhere?

Last but not least, E The overall sound is slightly on the warm side. Are there any tricks which would slightly boost the highs? Perhaps moving the speakers slightly further from the back walls would result in less room reinforcement of the bass frequencies. My uncle suggested adding power-related upgrades. Currently, there is no power-related enhancements and I was told that changing the power chords and adding some degree of power filtering would possibly enhance the highs a little. Would it be better to go for power regeneration instead?

Thanks in advance. After yesterdays listening session, I discovered that there is still a lot of work to be done

 

[spacemanspliff]

good luck. this is why I gave up on stereo for now and went to a 5.1 lol. bloody complicated when you HAVE to make one room conform. Next house I am building a sound room.

 

[spacemanspliff]

since nobody has replied I will hazard a guess. There's probably interference with the bass waves. The first thing to try is moving the speakers then the components. There's a sweet spot somewhere in that room you just have to search for it.

 

[milkpowder]

Not surprised by the lack of interest but thanks spacemanspliff. I know it's a very personal and boring problem that doesn't interest many

Luckily, I've got an uncle around who's very willing to help and a dad who doesn't mind spending on upgrades and listens to my uncle & I

My uncle's been measuring the dimensions of the room and working out the theoretical optimum speaker positions. I think there will be some movement to the speakers and surrounding furniture this weekend as well as some purchases. I think we're going to start with a PS Audio Duet Power Center and a xStream Statement power cable for the source and if we like the results, get another Duet and two more xStreams for the power and preamp. It'll probably be two Duets rather than a single Quintet because of wiring inconveniences.

Although no final decision has been made, we're siding with PS Audio over Shunyata because my uncle uses PS Audio himself and swears by them. Also, Shunyata is in general more expensive than PS Audio plus the fact that neither my dad or I have ventured into power-stuff before, we're [size=xx-small](read: he because he's paying. I'm fine with it as far as I'm concerned

)[/size] wary of spending far too much on something that may not make much of a difference. "Losing" $1k on a Duet and xStream Statement is far better than "losing" 6k on a V RAY and some Pythons.

As always, I'll be using my ears whilst leaning on calculations and rules for assistance.

 

[milkpowder]

The xStream Statement power cord has arrived! The local PSAudio dealer was out of Duets so that will have to wait. It's pretty darn thick and will become quite a hassle to manage if more are used

Will it make a difference? I haven't even plugged it in to the source because of some stupid family reunion dinner I have to go to a half an hour...

BTW, how do you read this name: Oyaide => Oh-yah-iday?

 

[Herbal]

A) Sounds like it just could be an issue with the speakers. You might be getting an impedence kick at 32Hz or the FS of the driver just doesn't bode well with reproducing that frequency. It's also possible that your experiencing the baffle effect where sound waves wrap around the speaker from the driver face and can cause certain frequencies to be aplified (which could cause 35Hz to be louder than 32Hz where 32Hz is at the 'correct' volume). Higher frequencies could be becuase of a poorly designed crossover or room interactions.

Ideally you don't want to place the speaker equidistant from two walls and this can cause room resonance to mess with the sound.

B) Could be room interaction, could be mismatch of drivers/crossover/cable/electronics not being perfectly matched/balanced.

C) Very few speakers will disappear accoustically as you say. The best way to try and achieve this is a perfectly desinged crossover producing a perfectly flat frequency response, time aligned driver placement, cabinet construction to remove baffle effects/frequency diffraction. A dipole speaker with an infinite baffle also provides a means of loosing the speaker in the background.

Once the speaker is perfect and the associated electronics it's time to then look at room interactions and acoustic treatment.

D) Considering bass frequencies will have a wavelength measured in feet/metre's it probably makes very little difference where your components are. It may help to isolate your components from floor resonance by means of isolation spikes and/or high quality audio racks.

E) May help if you rewire with high purity silver both internally and externally. Many people say that in comparison to copper they find silver to be 'brighter', i.e. taking out the 'warmth'


This is just some stuff I've picked up from my DIY experiences...not that it's correct or wrong. Take what you will.

 

[ooheadsoo]

Most of this is about room acoustics. You need to treat your room. Anyone who has done frequency sweeps will realize they have these problems. Just about nothing you can do with your speakers will solve A-C efficiently. As for panning outside the speakers, although it sounds disappointing, unless some weird phase effects are going on in the recording, they shouldn't exceed the L and R positions of the speakers. I would suggest taking the time to read these two articles:

Directional Hearing
http://regonaudio.com/Directional%20...o%20Stereo.htm
What can and cannot be expected from stereo
http://regonaudio.com/What%20Can%20a...%20Stereo.html

You need bass trapping and first reflection absorption or diffusion to solve your issues.

I think Herbal is right on D.

For E, I would wait until after room treatment to make a final decision, but if it really bugs you either EQ or different speakers are the suggestions I would make.

There were some acoustics links posted in a recent thread started by recstar24 if you're interested.

 

[JadeEast]

Do the sweeps and walk around your listening room
and you will be amazed at where standing waves will
cancel out some frequencies.

While we think we listen to loudspeakers we do listen
to allot of the room itself, one thing that headphones
eliminate.

Here is a link full of info.
http://www.linkwitzlab.com/rooms.htm

 

[ooheadsoo]

Linkwitz is full of dipole promoting material, of which most people are unable or unwilling to take advantage of. Regonaudio.com (REG is a math phd professor at UCLA) has more acoustics info as well as info on how recording techniques contribute to what we hear, although he is a proponent of dsp for bass. Realtraps.com has a lot of good info on broadband absorption, many of them magazine articles he's written for pro audio magazines over the years. Gikacoustics.com has an education link that has some more good general info.

To get started mapping out your bass issues, this link should help: http://www.audiocircle.com/circles/i...?topic=17842.0

 

[islewind]

Try some trial and error speaker repositioning, and some portable bass traps. The room has an immese impact on your sound, it would even be worth it to have someone measure your room and plug the dimenions into a computer model.

 

[milkpowder]

Thanks for the superb help guys.

Bass traps will be a bit of a problem since the room is 26' x 19' with a ceiling that's possibly 15'+ high. It would take a lot of traps to cover all the corners. I'm under the impression that bass traps will smooth out the bass response and actual bring out bass which was previously cancelled out. Is there any truth in this?

ooheadsoo: thanks for the links! They're really informative. You mention first reflection absorption: Due to original furniture setup, the stereo is currently placed so that it is at one end of the room firing widthwise rather than the more ideal length-wise placement. There is no way my dad will consider moving everything around because the sofas were custom made to fit. As a result, the LHS speaker is MUCH closer to the sidewall than the RHS speaker so the reflections from the RHS speaker will take much longer to bounce of the side wall than the LHS. Surprisingly, the overall imaging is not affected too much by the asymmetry. I'm not exactly sure why or whether this is indeed the case, but there may be a possibility that the asymmetry is causing some odd wave cancellations which have a detrimental effect on the overall sound. I wonder if tall, mobile partitions may help to maintain symmetry of the listening area. I believe I've seen some exhibitors at hifi shows use them.

I think we're going to put some slabs of granite or marble underneath each of the three components, but not until the position of the rig itself is finalised. It makes total sense that the woofers are not affected by adjacent gear though. Thanks for the clarification.

The panning outside the speaker issue is intriguing. I honestly hear sounds coming from outside the speakers! I also hear sounds coming from behind the speakers. It's scary and quite lifelike. I close my eyes and I can acoustically see the orchestra perform in front of me.

I know headphones are so much more convenient, but it's so worth getting speakers because of soundstage, bass impact and extension.

Regarding rewiring the internals, I'm definitely not going to be messing around with the speakers. They're supposed to be very good and the warranty would definitely be void should I try opening them up. I can't solder anyway

More about the PSAudio xStream Statement: Straight out of the box, it made the system sound different, although personally, I wouldn't be able to justify spending close to $700 on a 2.0m power cord (US products cost more in Hong Kong). The soundstage seems to have widened considerably and the overall sound more refined than before. The highs also seem better represented, so much so that I've had to use the tweeter grilles that came with the speakers to slightly dampen down the highs for one or two particular SACDs. I haven't listened to it since yesterday (left them playing overnight) so I'll probably report back again. What I can say for sure is that the cable itself is incredibly bulky. I can upload some pictures later.

Thanks again for all the help

 

[recstar24]

Don't have much to offer, other than I think you should really deal with room acoustics as a priority. My room modes are not as bad, but I know taking care of my reflections will help with imaging and I could easily smooth out my bass by treating my corners. I am going with GIK acoustics, and I have no doubt they will have a bigger impact on sound than an IC or power cord change.

 

[ooheadsoo]

Quote:

Originally Posted by milkpowder /img/forum/go_quote.gif Thanks for the superb help guys. Bass traps will be a bit of a problem since the room is 26' x 19' with a ceiling that's possibly 15'+ high. It would take a lot of traps to cover all the corners. I'm under the impression that bass traps will smooth out the bass response and actual bring out bass which was previously cancelled out. Is there any truth in this? ooheadsoo: thanks for the links! They're really informative. You mention first reflection absorption: Due to original furniture setup, the stereo is currently placed so that it is at one end of the room firing widthwise rather than the more ideal length-wise placement. There is no way my dad will consider moving everything around because the sofas were custom made to fit. As a result, the LHS speaker is MUCH closer to the sidewall than the RHS speaker so the reflections from the RHS speaker will take much longer to bounce of the side wall than the LHS. Surprisingly, the overall imaging is not affected too much by the asymmetry. I'm not exactly sure why or whether this is indeed the case, but there may be a possibility that the asymmetry is causing some odd wave cancellations which have a detrimental effect on the overall sound. I wonder if tall, mobile partitions may help to maintain symmetry of the listening area. I believe I've seen some exhibitors at hifi shows use them. I think we're going to put some slabs of granite or marble underneath each of the three components, but not until the position of the rig itself is finalised. It makes total sense that the woofers are not affected by adjacent gear though. Thanks for the clarification. The panning outside the speaker issue is intriguing. I honestly hear sounds coming from outside the speakers! I also hear sounds coming from behind the speakers. It's scary and quite lifelike. I close my eyes and I can acoustically see the orchestra perform in front of me.

Realtraps has triangular traps that can go in the corners at the ceiling. Gik as a triangular column trap that can go easily into corners. If you are interested in getting advice, just as I suggested to recstar, you might consider asking gik or realtraps about absorbing heavily near the LHS or a different approach. They'll help you even if you don't buy their product.

I would recommend reading the regonaudio links I posted earlier asap. They (and others on his site) explain why you would hear things outside the bounds of the speakers, especially on classical recordings where they may use widely spaced omni mics.

 

[milkpowder]

OMG! Massive improvements simply achieved by repositioning the speakers so that they're closer to the middle of the room. Now the left and right speakers are more equidistant from the side-walls than before. I also toed them in slightly and the sound is miles more coherent. The soundstage is now much more realistic and deeper than before. I'm getting less of the out-of-speaker soundstage and more substance between them. The bass is cleaner, but I haven't had time to test the extension and flatness yet.

I also have quite a nice python-sized speaker cable on loan so that might be helping a bit. The scary thing is, this $3k+ behemoth is not that much better than the $400 puny wire that I was using before! Talk about diminishing returns

Thanks for the advice ooheadsoo, I'm currently looking into these "traps", a new speaker cable and a power conditioner. I'm guessing the budget for the speaker cable is sub-$2500 for a 3.0m pair so if you have any recommendations, please tell me! The power conditioner is probably going to be a PS Audio Quintet, which PS Audio claims is better than the Shunyata Hydra 8 or any other passive power conditioner for that matter. I wonder how much truth there is in that statement.