Best Amp for Timbre, Depth and Spatial Resolution?

Does anybody know what should one do to alert the moderators about this individual. He is trashing one post after another.

Mapman, to me this sounds more like Forrest Gump than pro wrestling.

My initial intention when opening this thread in my browser was to actually share my opinion on the depth and spatial resolution. I'll try to convey also what I think Bo is meaning when he refers to 2D and 3D sound. As English is not my first language, I should apologies in advance for the occasional typos (the post is quite long). Also, since the atmosphere here is a bit "hot", and I was made aware a few times that I might come across as overconfident and/or patronizing, I should also say that this post is in no way meant to be condescending. (I write in English mostly technical/scientific stuff and that is why I might sound rigid and/or overconfident). So here it goes:

IMO, speaker placement is the most critical detail for obtaining a good depth and spatial resolution. Changing speakers, amplifiers, cd players, cables, etc. can only do so much if the speakers are not properly placed in ones room.

I'll start by note that most often people make sure that the speakers are orientated symmetrically with respect to their listening position, i.e. have the same distance and the same orientation and toe in. Unfortunately, very often that is not enough for obtaining the 3 dimensional sound often referred by Bo. While one obtains a centered voice and, for example, the guitar on the left side and the bass on the right side, everything is pretty much in the same plane, i.e. we have the 2 dimensional sound as referred by Bo. This happens because very often the walls in one's room are not identical from an acoustic point of view. As a result, even though the two speakers are placed symmetrically with respect to the listening position, their frequency response (and wave characteristics) of the two speakers are not similar at the listening position.

I'll give two common examples. First, below 300 Hz, the two speakers can have significantly different responses even when the two speakers are placed symmetrically with respect to the room's boundaries. (This happens because we have low standing waves formed due to reflections between the walls of the audio room, but also between the walls of other neighboring rooms with respect to which the speakers are not positioned semitonically.) A second example, is the case of L-shaped rooms, where one speaker is placed close to a corner while the other one close to an opening. In this case the speaker in the corner will not only put out more bas but will always sound a bit louder than the other one. Unless special measures are taken, both these situations will lead to a partial (or complete) loos of the three dimensional spatial information recored on the album.

The easiest way to solve this problem is to use a room correction software, which is what Bo is actually doing. He is using as pre-amplfier a high-end Onkyo home theater preamplifier which comes with Audyssey Pro software. Among other things, this software makes sure that the two speakers have identical responses at the listening chair. I have actually told him quite a few times that I believe his claims. However, I have also pointed out quite a few times that the timber of instruments is most often more important that the stereo image sound stage.

I'll stop here as the post has gotten very long. If the discussion goes well and people are interested, I will also post my thoughts about the effect of room correction on the timber.

Paul

That is certainly the case Charles1dad. He makes it very clear that he sells Pass Labs, Monitor Audio and Onkyo. I have no problem that he is a dealer. In fact, I have stated more than once that he is one of the very few dealers that recommends cheaper components over much more expensive ones. What I find wrong is that fact he is taking over every thread by repeating the same thing over and over again. Check for yourself what is the typical number of posts he is posting in a thread, and more importantly, if there are any significant differences between his posts.

Bo, you have never criticized the brands I use, and I have also made it very clear more than once that I too adhere to the benefits brought by room correction softwares. Also, what do you mean when you write:

Says someone from Holland.....

I live in The Netherlands but I am not dutch. However, I do not see how is that relevant for the present discussion.

Hi guys, of course people are free to post their opinions on this forum, and of course Bo is not the only one repeating himself. I've merely asked (albeit without a question mark) how can one alert a moderator. Moderators exist for a reason, plus, I am sure they will not censor one's posts (e.g. Bo's posts) only because another one (e.g. me) will ask them to do so.

The reason I have asked that question is because I felt that Bo has monopolized also this thread without offering any real advice. I invite, whoever thinks I am imagining things or that I have an agenda, to quickly check Bo's posts in the thread below:

Any bad experience with wilson audio sasha w/p?

Unfortunately, as other have mentioned, the thread above is not the only thread poisoned by him (with the same story). While I do not want him band, it would be really nice to have an ignore button.

Wolf, it is a typo of course. It should read "symmetrical" and not "semitonically". I have push the "Submit now" button instead of the "Preview firs" by mistake, and you guys have posted before I was able to edit the post. I'll get back to you regarding the effects of parallel and non-parallel walls.

Mapman, I could think at a number of factors. So in no particular order:

1) the spectra balance of the amp. Some amp-speaker combinations can emphasis (or de-emphasis) the frequencies that are more problematic (or less problematic) in one's room. Obviously this ultimately depends on one's room.

2) The ability of the amp to control the subwoofers.

3) Like with the response of the two speakers at the listening position, the amp is also suppose to have zero differences between the left and wright change. How large and/or significant such error are in reality, I do not know. But I can imagine that such differences exist and play a role, as not two components are identical.

Mapman and Wolf, I am only bouncing ideas.

My point is that if speakers placement has been optimized properly, one should still be able to detect small differences in soundstage when changing amp because of the reasons I have stated above. Of course, we talk about small differences. Further, because each amp controls the subwoofer of speaker differently, the speaker position might also need to be slightly changed when changing amps. Therefore, because most of these small differences are cause by the interactions between amp, speakers and room, IMO it is basically impossible to determine them by performing measurements on a single component (except maybe for point 3). One has to try the various amps in his room.

Wolf, some example: left channel has slightly higher distortions/volume then the right channel. I clearly stated that I do not know I significant/large such differences can be. Thus, it should have been clear that I was only a guess.

Ok here is the second part of my write-up:

To realize why room correction softwares yields a superior soundstage it is important to realize that:

On one hand, one does not want to excite room modes as that will lead to nasty bass resonances and nulls. Therefore, it is desirable to NOT place the speakers symmetrically with respect of the walls in the room. This is exactly what Wolf_Gargia has pointed out. However, on the other hand, to achieve a perfect soundstage, one has to place the speakers symmetrically with respect to room walls as one wants identical acoustic paths. Consequently, one is always faced with a dilemma to optimize the speaker position for the best bass response or for the best stereo image. (In the case of small speakers with limited bass output the situation is most often not critical and acceptable compromises can always be found. In the case of large speakers with healthy bass, however, this becomes problematic. In this second case, one's priority is always to optimize the position of the speaker to obtain the best bass response. Thus, having nor a "perfect" soundstage.)

Now, the reason Bo obtains a much better soundstage is because room correction systems, can actually optimize both issues mentioned above at the same time. Moreover, if one used two speakers and a subwoofer, the contradictory issue above is completely removed by sending all low frequencies to a separate subwoofer which can be placed anywhere in the room (e.g. the place that gives the best bass response). This is why Bo is crossing over his sub very high, I believe at 140 Hz or so. This in turn explains why REL subs are too slow for him - they are not design to play that high. Please also note that a similar approach is used also by Lyngdorf in their room correction procedure, i.e. in Lyngdorf system the subwoofers are crossed over at even higher frequencies, i.e. 250 - 300 Hz or os.

The opinions are very divided here. Some argue that when crossing over the sub so high one can get rig of most room resonances, while other argue that it is not a good thing as our ear will be able to detect the source of the low frequency. Since I simply do not know what is the right thing to do, I will just give both camps the benefit of the doubt and acknowledge that room correction has come a very long way.

I too use a room correction system, not a home-cinema Onkyo like Bo, but an Accuphase stereo unit that can not account for a sub and which most likely is not as advanced as the Audyssey Pro. While I had very few lab rats in my room (as I am not in the business like Bo) I too can attest that stereo purists (even very experienced ones), are extremely impress by the three dimensional and holographic stage obtained when using such softwares. This happens because they are not much aware of these "home theater tricks". They know they have done their homework at home and positioned the speakers correctly and in some cases even added acoustic treatments. However, they simply do not know/understand how crucial it is to have almost identical phases and frequency responses at the listing position from the two speakers and/or how easy is to perturb these parameters.

(I find this perfectly normal since as humans, i.e. we are not waves, we have very little feeling for phenomena like interference. I am a physicist and I have spent countless hour in the lab aligning and tuning lasers. While I am fully aware of how crucial is to have an exact phase and/or wavelength in the lab, I too was very surprised the first time I have heard a truly holographic sound stage - not surprizing given the fact that in the lab I was using an oscilloscope, i.e. not my ears.)

What I have found very interesting and funny at the same time is the fact that home-theater geeks, are much less impressed, if at all, to hear this holographic soundstage. They typically comment something like "big deal … you have used something like Audyssey XT with your Accuphase system to obtain a three dimensional static image… my home cinema system makes things flying around me ". The first time I was told this I was perplex. My friend's answer took me totally by surprise. . :)

Regarding timber and room correction software:

My experience (with the unit that I use) is that to obtain an accurate timber when using room correction softwares, it is crucial to use the room correction software as little as possible. That is, one has to place the speakers (and subwoofer if applicable) in the best place possible, so only minimal corrections need to be applied. It is very easy to screw things up, and suck the life out of the music, especially if one is naive enough to think that you can place the speakers randomly in the room and let the software take care of everything else. (Most likely, I am not the only one here who has heard room correction softwares sucking the life out of the music while at the same time giving a perfect holographic soundstage.)

Now, it seems to me that Bo here, is one of those home-theater-tech-guys that sets up Audyssey based systems in people's home - a rather common thing in the home theater business, I might add. Therefore, he most likely knows what he is doing and as a result most of the time he
obtains a satisfying timber along with the holographic soundstage. I am very sure that timber accuracy is the reason why Bo insists that Pass Labs amps are so important in his set up - he needs to inject some life into an otherwise rather sterile/cold system (Onkyo and Monitor Audio Platinum) - my opinion of course. Therefore, knowing the reactions of my few audiophile friends to the 3D soundstage in my room, I have no doubt that Bo is impressing many of his clients big time with his demos.

However, people should realize two important things. First, most recordings (and especially the rock ones) do not contain much, if any, holographic three-dimentional information encoded on them. (I am talking about 3D not 2D soundstage). Therefore, while impressive in a demo (with specific songs), such systems will most likely not be as impressive when playing one's entire album collection. Some specific recordings will certainly sound very impressive but only a very small percent of one's collection. Secondly, one can not conclude that because of its significantly superior soundstage a system with room correction is clearly superior to a system without room correction.

As it turns out (see the quotes below), this is exactly what Bo is doing when drawing conclusions about many of the components he is trashing. This should be very clear from his post above:

6 months ago I listend to the latest 800D. The image was almost flat at the show. I was at the same show and I had a very deep and wide stage with the same music.

Similarly, in the thread:

Why are subwoofers so polarizing?

he writes:

What I do is I send clients to shops were they sell Velodyne. It is not my responsibility how they do there demo. This is a very easy way to convince. I never heard a demo of a Velodyne at a show that I was thrilled. I Always have my own cd's with me.

I let you draw your own conclusions.

Paraneer, IMO the brand that Bo is trashing the most is Wilson. Apparently, they are not good for the typical Dutch house and Wilson Audio is not informing the people about this. =))

Regarding your comment

Keep them coming Bo because I can't stop laughing either.

I for one, I am not sure whether I want to start laughing or crying.

Springbok10, I agree 100 percent with your first post here. That is why I have asked in my first post here how does one alert the moderators about this guy.