I've always considered equalizing a mythical beast, or something that happens only for other people. But I guess it had to happen sooner or later, in this case ever since I bought new speakers.

I replaced my trusty Wharfedale Diamond 8.2's (a bookshelf speaker) with brand new Wharfedale Diamond 8.4's (heavy-duty floor standing) and that's when the problems started. My first impression of those speakers was "my god, are these things broken or what?". The music sounded very thin and artificial, as if something important was missing. The speakers were placed against a wall. I remembered wall reflection interference, and pulled the speakers about one meter away from the wall and was awestruck by the sound. Brilliant, absolutely brilliant, nothing lacking at all. Too bad I can't possibly keep the speakers in the middle of the floor.

With the help of sine waves, sine sweeps and music with foobar2k equalizer I figured out that when in close proximity to wall, at least frequencies around 300 Hz - 500 Hz were attenuated by 2 - 3 decibels. Not to mention the eardrum-wearing boomy bass. With the help of fb2k parametric equalizer, I was able to enhance the next-to-wall sound greatly, to almost natural levels. While equalizing can in this case definetely improve the sound, the complete and accurate dampened frequency response curve of the speakers remains unknown to me. The proximity to wall could cause amplitude gains and attenuations everywhere that might go unnoticed because I don't have any reference speakers next to the Wharfes.

Well, equalization sounds like an "easy" solution (actually it's not very easy at all) but there's still something I'm not sure about. I mean, aren't you supposed to get equipment that doesn't need equalizing to begin with? Isn't equalizing just a poor man's last resort in a hopeless situation? Doesn't the need of equalization itself indicate you should get better equipment? What I'm asking here is that is equalizing "ethically" the right thing to do under any circumstances? I'm inclined to believe it's not. I wonder wheter compensating for room acoustics can be considered as a gray area or not. I also wonder which would be more efficient by a longshot, software equalizing or physical tricks like jamming a sock in the reflex tube and covering the speaker rear with thick mattress or something.

I'm somewhat disappointed in myself for making the purchase decision. The benefit of the smaller speakers is that they are much easier to place. My room is way too small for large 3-way speakers and I still decided to purchase the 8.4's after falling in love with them at a hifi store. At the store's listening room, the speakers delivered pure sonic bliss, everything I could possibly want from sound. At home I'm stuck with virtually unusable (without equalizing that is) and heavy cup holders. At least they are pretty to look at, so I can use them as decoration elements

One other thing is my amplifier. It was ridiculously underpowered for the Diamond 8.2's, let alone these floorstanders. The amplifier is a cheapo 2 x 38 W Technics SU-V500. It's known for astonishing levels of harmonic distortion and almost complete inability to deliver any amperage. How does exactly a typical amplifier react when trying to drive too large speakers? I already know about clipping (generates plethora of high-frequency noise) but are there any other audible effects too? I assume the impedance value of the speakers drops noticably when approaching lower frequencies, so could it be possible the amplifier simply cannot give enough raw current for low-midrange sounds?

In order to reach comfortable listening levels with the speakers, I have to turn the volume knob to about 11 o'clock position. I hear most cheap amplifiers give practically maximum power at this volume level. Could it be possible that the amplifier actually causes some of the 300 Hz - 500 Hz attenuation I so readily notice? And or in any case, do you think I could benefit from a better amplifier?

The purpose of this post is to inquire, but also to warn and to share experiences. If someone has been in a similar situation and managed to improve the situation without tearing a few walls down, I would very much like to hear about it

@niktheblak:


I know about the graphic equalizer in fb2k and there has been several discussions about a parametric EQ, but I didn't know there was a parametric EQ for fb2k. Did you really mean the graphic EQ? A parametric would be much better for what you are trying to do. I'm waiting patiently for a fb2k parametric EQ.

The room-speaker acoustic interaction is a complex 3 dimentional one. Generally the interactions affect frequencies below about 350Hz. As you found, moving the speakers around relative to the listening position makes a huge difference (better/worse).

Getting flat in-room system performance at the listening position is nearly impossible. Even if you had "perfect" speakers the room would create significant problems. So if you had both an ideal speaker and an ideal room then yes, ideally we would not want to use equalization. In the real world, well applied equalization can make a huge difference. Well applied is not an easy thing to do - you need to be able to measure the frequency response and know how to apply EQ which can be an art and a matter of taste. For example, an acoustic null at a certain frequency can not typically be compensated for with an EQ boost - standing waves will null no matter how much you boost, so trying to boost a null will just overload the amplifier and speaker. Then there are considerations for signal clipping, acoustic energy stored in walls/floors, etc.

It is possible that your new speakers have a lower impedance in the bass which is harder for your amplifier to drive. This is typically not nearly as severe a problem as room acoustics, but the best way to test would be to try another amplifier. I wouldn't put any stock in the position of the volume knob - there are a number of gain factors between products (CD player/soundcard output levels, total amplifier gain available, speaker efficiency, room acoustic gain, average volume level of the audio file, etc.) to make any conclusions just based on the knob position.

All else being equal a larger speaker enclosure should be more efficient and require less power. This may not be the case for your two different systems.

You may want to check out this simple free Excel spreadsheet to calculate the room interaction in the low frequencies to determine the best place to put the speakers and your listening position:

Room Acoustic Calculator

It is always good to experiment with room treatments, etc. but remember that typically below about 350Hz you are dealing with standing waves / speaker/room interactions and above that you are dealing with reflections, reveberation times, etc. Carpet, padding, furniture, etc. typically affect above 350Hz. Listening position, speaker position, speaker performance, and room acoustics affect below 350Hz.

I've fought this battle for years in several listening rooms. Suggest you get a Radio Shack sound pressure level meter (SPL meter) and do some frequency response measurements at your listening position if you want to really fix some problems.

Another trick is to put one speaker in your listening position playing some low frequency tones or music with bass you know well on repeat, and walk around the room. Since acoustic reciprocity holds, the sound you hear at any position in the room (in the bass) is essentially the same sound you would hear if the speaker was placed where you are standing and you listen from where the speaker is currently playing. This is way easier than moving the speaker all around the room and then listening and trying to remember which one was "better."

Good luck.

Yes, I did. Winamp had the parametric equalizer through Shibatch's Super Equalizer plugin. My mistake.



That's sort of a relief. At least my speakers aren't faulty . Honestly, I knew that listening environment affects the sound, but I didn't really grasp the real magnitude of the problem with my previous speakers.



I made that assumption about maximum amplifier output from the following general issues:

- The speakers have very low sensitivity value, around 84 dB's and thus low efficinecy
- Terratec's mixer shows about -2 to -3 dB of maximum output signal level when playing overcompressed music (volume level doesn't seem change at all)
- The perceived volume level doesn't change at all when I turn the knob further. It just begins to sound distorted.

Of course that's just a rough estimation, but I tend to think the amplifier is outputting maximum wattage.

By the way, thank you very much for the information. Whilst I'm not any happier, at least I'm a bit wiser now

Hmm.... Although this is borderline off-topic, I should mention to you that at least in Winamp's Grapic Eq (the one that it comes with), MPCs tend to distort. Dunno about parametric EQ or Fb2k.

This is more of a question for DigitalMan, but anyone can and should answer. I ran some a sine sweep and discovered that I there are some frequencies that sound distant or out of phase (3 or 4 from 200Hz to 80Hz). Since I've determined that it's the room and not the equipment, is there any elegant solution to this problem (aside from move)?

I'm not sure if it's an acoustic nullpoint or not. Does anyone know of a good frequency generator so that I can isolate specific frequencies and determine if they're location dependent?

Anytime you boost you can cause distortion/overload. Should not be unique to MPC. This is one reason that an acoustic compensation EQ typically only cuts/attenuates in bands.

I believe that Foobar2000 has a built in tone generator (see Preferences, Input, Standard Inputs menu) that should be up to the task. Be very careful with volume level - easy to damage speakers with tones.

Elegant solution? Well, depends on your definition of elegant, but its an acoustics/physics problem so you need to address it at that level. So you need to move the speakers, move the listening location, or change the room. You could add a subwoofer to the system - sometimes the flexibility of placing the subwoofer in the optimal location outweighs the other issues (cost, cables, integration with satelites, etc.). There are some companies that make "bass traps" which are large contraptions designed to reduce the effects of the standing waves that attenuate certain bass frequencies.

Download the Excel spreadsheet I linked to to calculate the frequencies that will be due to room modes. The nulls will absolutely be location dependent. Sometimes moving speakers or listening position 0.3 to 1 meter can make a dramatic difference, which may be your elegant solution. Play a low frequency tone in one of your nulls and then walk around the room to hear for yourself how large a factor location is.

The bad news is that you will probably not be able to eliminate the nulls, but minimize them and move them to frequencies that are not as objectionable.

You should really consider a more powerful amplifier. Try borrowing one from a local hifi-store. It should be possible.
And I also got the impression that your speakers are quite new. All new speakers must be well run in before the sound as they should.
It usually takes 50-100 hours, in some rare cases even more. And of course speaker-placement IS a big issue.

Good luck!

Nope. My speakers sound the same they sounded the first day. What usually "runs well" is the listener, until he gets used to the speakers.


Where did you get this figure from?


On the other side, that is true.

Most speakers doesn't sound very well the first hours of playing.
The membranes are stiff and need time to "run in".
In the beginning the tweeter may have a harsh sound and the bass may be lacking.

The figure 50-100 hours was just a figure I came up with, nothing scientific.
Some speakers may sound ok from the very beginning while some need some time.
Dali 8008 is an example that need some time to sound good.
My brother just bought a couple, and at the beginning the tweeter was very harsh
but after a while of playing (perhaps 24 hours or so), the tweeter sound more pleasant/softer.
And it is not because I got used to the way the speaker sound, I guarantee.

If all materials are going to soften due to continuous use we are all in big trouble. Why do the 'membranes' soften to a point and then stop softening, then?


Better 'ABX' your conclusion with used and new speakers of the same model, if you have the money.
There are some things that definitely have to be 'run-in', like running shoes (Even then, the feet also get used to the freshly manufactured material).
Speakers definitely do not need to be run-in (Or maybe just give them a good shake for 10 minutes before you listen with them...may make a big difference...all tones sound ultra-pure, mpcs have 110% quality, definitely a time-saving exercise).

Someone has not been reading his mpc plugin documentation. Go read it again, this time not skipping over the built-in equaliser part.

Is that really so incredible? It reads in the manual of the speakers that we should do this. Why would they write that if it doesn't matter? Why should I trust you more than them? (I mean it's not like they will make more money from telling people to do this procedure...)

I had to place my large floorstanders about 1.5m into the room, with 1m from the side walls to the woofers' center in order to get the best balance between bass & mids. So if you have 'big' speakers:

1) Get at least a REAL 60W amplifier (should rate above 250-300W power consumption on the back). I know a friend who had a '100W' SONY and blew his tweeters twice (Infinity Alpha 30) before deciding to change it for a Harman Kardon that had only 40W but really delivered that power.
2) Floorstanders DO not sound good when placed in corners or near walls. They need to breathe (to express this empirically).

I don't know the nitty gritty behind this, but the run-in time is quite a well-known issue. And I don't think it's just placebo.


Well, if it was financially defensible I would definately ABX, but now it's not. So I just have to rely on my hearing/memory.
And I can also ask you the same question, why do shoes stop softening at a point.


I think it makes a big difference, and since you're swedish, try reading the forum minhembio.com, there you'll find some interesting posts about run-in time.

I don't think a well-made equalizer distorts the sound noticably. Remember, DSP equalizers are in widespread use everywhere. And DSP equalizers have a pretty lousy CPU compared to modern PC's so why on earth wouldn't a modern PC beat a high quality super-expensive digital equalizer at every possible aspect?

Surely, equalizing requires pretty intense calculations on the signal data (fft convolution mostly) but the negative effect of that is nowhere near the effect of unsuitable listening environment and bad speaker positioning.

And I don't use Winamp's built-in equalizer. I use the Shibatch's super equalizer plugin, the same fb2k uses.

I guess my next purchase will indeed be a better amplifier. Even the speakers' manual recommends having plenty of output power reserves. Too bad good stereo amps are pretty rare nowadays, damn those popular 6-ch Dolby toys! I'm currently searching for a good deal on a powerful second-hand stereo amp.

I don't believe in the speaker "wear-in" concept. I bought my previous speakers (Wharfedale Diamond 8.2's) as brand new and their sound didn't change a bit during 18 months. Actually they sounded better at first because the sound of the speakers was new and exciting. When I got used to the sound, it wasn't new and exciting anymore and thus got a bit dull.

And yes, believe me, I've noticed that floorstanders don't sound good when placed near to a wall. The placement really makes a world of difference, like you're listening to totally different pair of speakers!

Ok. Let's put this speaker "run-in" time aside. We just have to accept that some think a speaker needs "run-in" time and some don't.
If it's placebo or not, we let it to be unspoken.
Anyway, I think we all can agree that a more powerful amplifier would do a big difference, at least it did for me.
Going from a Pioneer VSX-511 to a H/K 5500 really made a big difference with my Infinity Alpha 50.

well, this discussion is odd. I will give every speaker a run-in time before I throw it away

Regarding your questions about underpowered speakers. Here are a few articles:

http://jblpro.com/pub/technote/lowpower.pdf
http://www.audiovisualdevices.com.au/downl...ane/note128.pdf

There are more but I can't remember where to find them. There are many articles on using DSP techniques to compensate for room acoustic losses and gains as well as for inherent loudspeaker non-linearities. Most methods seem to be very complicated still (to me) but I think advancement in this field will result in very positive outcomes for you and me.

I was against equalization for a long time, but I now believe that it is the only way to get very good response in an average room. Even if your speaker has a flat frequency response with a deviation of 0.5dB from the reference level on the range of 20Hz to 20KHz, as measured in an anechoic chamber. Once you place it in your room, that response will most likely be gone - even though sound will still be very enjoyable. Therefore, compensating for room acoustic non-linearities is your duty, if you want the loudspeaker to be able to do what it really can.

Of course not everyone has a thousand dollar microphone and software like SIA Smaart (I know I don't - but I have worked with it before) and therefore equalizing to get flat response is practically out of the question - getting "better" sound is a different story.

It is kind of ironic that sometimes, due to the reponse of your room, a loudspeaker which actually has MORE non-linearities (but ones that compensate for dips and peaks in the room's response) should theoretically sound better than a perfectly flat loudspeaker in the same room. Don't you think?!

Oh yea, speaker run-in time. Just keep in mind that the same people advocate "concepts" like this, who try to get you to believe that audio cables made out of crazy materials sound better than 99.999% pure conductive copper, simply becuse of their atomic structure and because of their molded shape inside the insulator. Also, these are the same people who try to sell you AC power line conditioners that are advertised to remove the "bad" electrons via quantum mechanical processes.

EDIT: I mean, why should the cones (membranes, whatever you want to call them) soften up? Cones for woofers for instance SHOULD be rigid, because otherwise there would be a bunch of intermodulation distortion due to the cone wiggling radially as it moves in and out at greater amplitudes. Just my opinion.

I'm not saying it's BS, but I certainley think so.

EDIT: Just a little something to backup a few of my claims -

INTERMODULATION DISTORTION
Intermodulation distortion is a type of distortion
where non-linearities in the signal path generate
modulation between all the frequency components of
the signal. The primary source for IM distortion in the
audio signal path is the loudspeaker. This is due to the
non-linear behaviour of the speaker cone, which of course
depends on the loudspeaker type and quality.

from document: http://www.digitalaudio.dk/technical_papers/aid.pdf

I've seen a lot of this crap in my short time on this forum . It's pretty unbelievable.
So I find it hard to believe most other claims about speaker 'optimisations'.


If it's placebo, I think the official policy of this forum is to ABX it, OR assume that it's false and not worth mentioning at all.
Also, the onus of ABXing falls on the advocate, not the sceptic.

Once again: They can make a lot of money if they can convince people to buy expensive cables, but there is nothing to be won on recommending a "run-in" period. So why do that?

Not saying that there is a difference though. I bought my speakers second hand so I had no chance to try this.

As has been stated before, speaker placement has a large impact. So if you get good sound by moving your speakers, obviously their previous position was suboptimal. With this you have also proven to yourself, that your amplifier can provide enough power to create this sound. This also rules out the break-in theory. A better amplifier will probably not cure the symptoms. Equalizition is perfectly legit to [edit] achieve a flat response [/edit]. Have you considered a new furniture layout, since this is probably your best bet? Spice up your life with a living room makeover.

edit: Thx, ErikS.

Erm. Sorry, but equalizing is a linear operation. You can never compensate for non linear distortion with an equalizer. And to be honest I can't follow your chain of proof that weak amplifiers and break-in don't affect the sound...

Edit: Ahh.. When reading your post again I thought that you maybe meant "flat frequency response" instead of "non linearities". Then I agree Language differences can be tricky...

I am not saying that a decent amplifier or some break-in time wouldn't genrally affect the sound. (Not sure about breaking-in, but I don't know enough to argue. There's the same debate about headphones. Some say they have to break in each use; the break-in time lasts only a few seconds. Others recommend playing high level pink noise through new headphones for a day or two. Others say it has no effect. *shrugs*)

What I'm trying to say should be true in this particular situation: if moving the speakers results in incredible sound then the speaker placement is by far the greatest problem. As stated, bad speaker placement will give you standing waves along with cancellation and overpowering which shouldn't be affected by the amplifier. A new amplifier will not cure those specific symptoms (except maybe for phase and frequency shifts which should be neglegible and would only "shift" the problem slightly).

I don't know if "run-in" exists or not, but I've heard salesmen using this argument thrice (twice with me, once with another consumer) in order to wipe out complains about bad sound.

Once, I told that the external DAC I had bought had not a good sound compared to the internal DAC of my CD Player. I was told that it was because the run-in was not finished.
Me and another speaker consumer reported our opinuions about the speakers we bought, some good points, some bad points. We were told that the bad points would disappear after a run-in period of time.

And the best of : I told that the color of the wood of the speakers was not as red as the one I had chosen. The salesman told me that it would turn more red after some exposure to ambient light !

Being sceptical is a good thing, but then sometimes people tend to overlook things that sound suspicious and yet are true. In my previous post I went all out about the BS people are trying to feed each other in order to prove why one cable sounds better than the other. A lot of this is BS, but there are some truths as far as I know and I don't want anyone reading this forum to think that it is all BS and not look after it on there own.

The truth is, there ARE differences between cables (sometimes audible, sometimes not) for instance. Electrical engineers WOULD like to think of cables as pure resistors, ones with low resistance. But cables have capacitance and inductance characteristics too. Different frequencies of AC voltages result in different outcomes. Insultation from electromagnetic noise is of course a big difference in cables. Parallel conducting wires add noise to each other through crosstalk.

There is a ton of other shit I can't even begin to understand that adds distortion to the signal (probably not atomic structure) and this should not be overlooked. Not all of it is audible so I wouldn't worry about it too much unless your cables are pretty long, but just remember that it is out there.

I don't have very much experience in this area, I am still a student, but I certainly couldn't tell the difference between a Circuit City audio cable and a Vandersteen audio cable. Instead of saying in my previous post that it is pure BS, I think I should have said that it is not practical to invest money into expensive cables.

You might find this to be a good read: http://www.audiocontrol.com/techpapers/tec...echpaper107.pdf

Only very crappy or broken cables can cause audible differences in case of interconnects. In case of speakers, an appropiate section is enough to make dissapear all audible differences.



Electrical engineers know this, of course. That's why they are engineers, don't you think so? The thing is how important is the influence of all those parameters at audio frequencies and at cables intended use.



In question of cables, all exotic cable is BS, since cable physics is not complicated, and there's no magic in it.

And not to mention, when putting things into the context of this thread, the negative effect "bad-quality wire" or wiring could possibly cause is no where near the problem of poor room acoustics.

I find it rather amusing that people are crying about wiring (not in this thread but in general) when their room acoustics alone totally rapes and ruins the music

Imagine; room acoustics can efficiently null some frequencies completely and cause variations of even 6 dB's all over the signal's frequency domain. Now what could a lousy wire possibly do that's even remotely comparable to that?

Well, the point of my post was to discourage this kind of behavior. The physics isn't as simple as you think, it is just simplified all of the time, especially when it comes to electrical phenomena.

Once you dive into electromagnetic field theory, physics isn't simple anymore. Cable capacitance, inductance and corsstalk for instance are NOT BS!!! They are measurable and their results are easily displayed with an good oscilloscope. They contriubute to distortion and given the proper cable lengths, they can lead to audible distortion - why is it so hard to believe that introduced electromagnetic noise can be audible? The point of my post was that in most cases these don't really make a difference in audio quality. But by no means are these physical qualities BS!

Room acoustics considerations are of course very important. They are also the hardest to control - many times, there is no solution possible. Use fiberglass panels of the appropriate thickness to rid yourself of as many reflections as possible. Tilt your speakers inward toward the sweet spot. Put a bass tube in the corner (if you are willing to sacrifice some aesthetics) and pray for the best. Usually this is enough.

Sure, there are spots in the room where individual frequencies are completely dead. This is a bad thing, but there is not much you can do about that... sorry. I haven't had very many problems with room acoustics, my room seems very ideal for the speakers I built.

I know. I study computer science and physics. Actually, relativity/qed is where physics isn't simple anymore, but let's not go into that now

I'm pretty well aware and fond of theoretical electrics (except esoteric appliances of Gauss's law but let's not go into that either), but I studied and pondered it at general level. I haven't performed a through case study on musical equipment as of yet. Nevertheless, I'm prepared to make an educated guess that the effect of phenomena related to electric and magnetic fields (including induction current) when considering speaker/interconnect wiring is at least some orders-of-magnitude lower than signal level, let alone that of speaker design and room acoustics. I reckon at least electromagnetic effects can be left totally out of consideration if using shielded (=coaxial) signal cable or in speaker cables, where the current levels are high.

Naturally if you're going to use kilometer of cable wrapped in a tight coil or set up a hifi system inside an electric locomotive or perhaps inside a power plant, things are a bit different

Edit:

Grammar and analogy

niktheblak:

The post wasn't aimed at you. And yes, I was talking about cable lengths used in professional audio. I hope you realize, in the pro audio industry these are pretty serious problems. For instance, the project my company is working on right now requires many miles of audio cable...

I think I know something about the physics. I'm an engineer myself (EE in some parts) , and have done some research for detailed information over cable interactions, just to be able to throw away BS. Many times cable interaction is simplified because the parts thrown away are not important. But I do know abouth those interactions, same as many regulars here, simply because it is not that difficult: resistance, inductance, capacitance, skin effect, interference pickup, crosstalk, transmission line effects (signal reflections), dielectric absorption, microphonics, thermal noise. I listed all ones I rememember right now, and I think there are no more real interactions. Some of those are related to some of the other ones. The four last ones are totally irrelevant at audio frequencies and audio levels. The others are not relevant at usual cable lenghts and intended use.



When did I say otherwise? All I said is that one has to quantify how much influence have those cable properties into actual sound, for human hearing, and for cable intended use.



It is not hard to believe. But at usual lengths, it is very doubtful it will be audible. Interconnect noise pickup is below -95 dBFS at tests done at home wih my soundcards and a cheap 1 meter interconnect cable, very close to the computer. It is tough to measure, because the noise is at the limits of my soundcard recording capabilities.



Again, read my post, I didn't say otherwise. But there's nothing in an expensive exotic cable that makes it different from a good inexpensive cable. And most times even a cheap stock cable (as long as it is not broken) is as good as anything you can buy, specially in case of interconnects. In case of speaker cable all you need is an appropiate cable thickness. The BS is at the explanations given from exotic cable manufacturers and audiophiles.

That's perfectly OK KikeG!

Thank you for your opinions!