Question for Anthony Cordesman & other reviewers - Thiel
EBIT -- Mon, 11/03/2008 - 18:55
Dear Anthony Cordesman
(Asking the question again)
You mentioned in your review of the Thiel 3.7, ".... you will hear the hardness and excessive upper-octave energy that is actually present on far too many classical recordings ..... and .... the bad moments of tenor and, particularly, soprano voice."
While a lot of early vinyl LPs had RIAA EQ that did not match the standard agreed industry curves that can emphasise upper-octave energy, there are other problems that can give a very similar impression.
Can you please confirm a couple of things for me about your reviewing practices (and other reviewers too, if you know):
1. As your reference equipment allows appropriate switching, do you experiment with absolute polarity settings for each of the recordings that show the adverse sound quality tendencies you describe above?
2. Additionally, if it is vinyl do you “also at the same time†experiment with VTA through finite arm height adjustments for those individual records to ensure inaccurate settings are not the cause of the unsatisfactory sound quality?
Loudspeakers like the Thiel 3.7, designed with phase coherence and alignment, delivering an excellent all positive step response make identification of SQ distortions from incorrect settings of Absolute Polarity & VTA reasonably obvious.
I am trying to get an indication whether you (and other TAS reviewers) acknowledge and treat Absolute Polarity and VTA with care during the review process, and thus avoid any possibility that resulting sound quality distortions could influence your review conclusions.
Many thanks
Frank
I take two approaches to polarity. First, I hook up the equipment according the the manufacturers instructions. Some, like conrad-johnson are quite explicit about their equipment being phase inverting. Second, I check polarity on several discs to see if this is a possible issue with set-up. Beyond that, I don't switch polarity. I don't believe that most people test and mark polarity settings by disc. I'm looking for patterns of behavior in the equipment when used as I understand the product will be used.
There is currently some debate about VTA adjustments. Some designers believe that VTA tweaking only reduces tracing accuracy, though sometimes this will happen in a complimentary way to the behavior of a particular component. Thus, VTA shouldn't be adjusted in testing. Others will disagree. Again, I think most users won't get this tweaky, and generally this isn't needed to describe the characteristic aspects of a product.
There are other systems issues that are more problematic than these (bass performance, for example, is highly room dependent). In the end, testing is imperfect and can only be directionally correct. The reader/prospective purchaser can see if he/she hears the same patterns. If he/she does, and those patterns seem desirable, then product might be considered for purchase.
Tom
"I hook up the equipment according the manufacturers instructions. Some, like Conrad-Johnson are quite explicit about their equipment being phase inverting."
Herein lies the first setup problem. Would manufacturers specify absolute polarity if they didn’t consider it important? If a reviewer doesn’t identify that the new unit being tested is reverse AP to their reference amp being replaced, how can the reviewer guarantee the right review conclusions. The reviewer must either reset the system setup so as it delivers the same absolute polarity with both amps or have easy AP switching options.
"I don't switch polarity. I don't believe that most people test and mark polarity settings by disc."
You are correct most people don’t - reviewers should! Firstly for basic system for comparability with other test units, secondly to compensate for the variation in AP on recordings. Because people don't, does not mean that it is not worth doing. All they need is the system functionality. IMO, all reviewers should have AP switching system functionality if they are going to do their "jobs" properly.
"Some designers believe that VTA tweaking only reduces tracing accuracy, though sometimes this will happen in a complimentary way to the behavior of a particular component. Thus, VTA shouldn't be adjusted in testing. Others will disagree."
Put me in the STRONGLY disagreeing camp. It has only been in recent years that more tone arms have allowed minute easy repeatable changes in arm height. With any one of these arms in a good system (AP correct of course) it is simple to demonstrate (on a central track - no tracing distortion) that movements in arm height of less than 5 thousands of an inch around the correct VTA are very easy to discern, and that such changes seriously degrade SQ.
"Again, I think most users won't get this tweaky"
Here we are in agreement. It is a pain, but the reward is better reproduction for a very low cost. BUT most importantly reviewers should/must be this tweaky if they want to present information we audiophiles can rely upon. I am surprised no manufacturer has designed precise repeatable VTA adjustment via remote control. With some of the extraordinary prices being charged you would think it possible.
Cheers
Frank
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