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Conrad-Johnson It just sounds right

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  #21  
Old 07-11-2016, 10:59 PM
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turntable turntable is offline
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Originally Posted by stereoquest View Post
Plurn,

What do you think is happening to the speakers driver when wired in or out of phase ? When the coil receives current in phase the driver is forced outward ...... Out of phase it is pulled inward . The two sound very different . With most Wilson speakers it will be more obvious becsuse the mid is wired out of phase with the bass driver .... Out of phase will cause loss of bass and accentuated treble in this speaker which is is easily heard..

What is concerning regarding the review is the reviewer does not actually know what product he has . He writes about the se model but clearly shows the standard version he then goes on to ' correct ' phase of the sub -- and leave the speakers out of phase ..... He does not know what he is doing but knows something is not right . I have never heard any tubed cj product ever have the traits he was referring to . He definitely got it badly wrong .
All very true. I have been using cj pre amps for a long time and with my previous Sonus Fabers it was also very easy to hear if wired incorrectly.

Plurn, reverse the positive and negative connection on your speaker wire going into the speaker terminals and play some of the same music. Will take you less than one minute. You will easily hear something is wrong.

Cheers
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  #22  
Old 07-12-2016, 02:58 AM
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Jerome W Jerome W is offline
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I agree with Shane.

For both my Gat and my Premier 17LS, when the speakers are phase inverted, I can hear the difference easily. But I must be at the sweet spot.
Elsewhere in the room this is not always obvious.
I had the system playing with inverted phase when E. came to visit and since I was not at the sweet spot I did not realize it.
But putting back the speakers on phase with the CJ preamp ( + connection with - of the cable ) made a huge difference even not being at the sweet spot.
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  #23  
Old 07-12-2016, 07:54 AM
plurn plurn is offline
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Quote:
Originally Posted by stereoquest View Post
Plurn,

What do you think is happening to the speakers driver when wired in or out of phase ? When the coil receives current in phase the driver is forced outward ...... Out of phase it is pulled inward . The two sound very different .
What I think is happening is pretty much as you describe except your conclusion that the two sound very different is debatable.


Quote:
Originally Posted by stereoquest View Post
With most Wilson speakers it will be more obvious becsuse the mid is wired out of phase with the bass driver .... Out of phase will cause loss of bass and accentuated treble in this speaker which is is easily heard..

What is concerning regarding the review is the reviewer does not actually know what product he has . He writes about the se model but clearly shows the standard version he then goes on to ' correct ' phase of the sub -- and leave the speakers out of phase ..... He does not know what he is doing but knows something is not right . I have never heard any tubed cj product ever have the traits he was referring to . He definitely got it badly wrong .

This does go back to my earlier questions that would be helpful if someone addressed. Lets take these Wilson speakers for example. If the mid is wired out of phase with the bass driver, which driver is in correct phase and which is inverted when the system is in correct phase? Are midrange frequencies or bass more important when it comes to phase? What we are saying here is that Wilson speakers are always playing music both inverted phase and correct phase at the same time. If you swap the plus and minus of the cables at the speakers, the Wilsons are still playing music both inverted phase and correct phase at the same time, just that midrange and the bass has taken turns of being in correct phase.

I found a Stereophile review of Wilson Maxx 3 speakers and they say this:

"The tweeter (the sharp up-down spike at 5.5ms) is connected in positive acoustic polarity, and the negative-going overshoot of its step smoothly blends into the step output of the midrange units, which are connected in inverted acoustic polarity. Their step in turn smoothly blends into the slower, later, positive-going arrival of the woofers' output."

They use the terms "positive acoustic polarity" and "inverted acoustic polarity" but these are equivalent to "correct phase" and "inverted phase".

So in the case of the Wilson Maxx 3, if you wire the speakers up in correct phase so that the positive electrical signal goes to the positive terminal on the speakers, your midrange would be in inverted phase (inverted acoustic polarity).

Does this mean Wilson thinks that the midrange does not need to be in correct phase but the bass and treble must be in correct phase? Isn't midrange more important for music - so the midrange should be in correct phase? These are not idle questions - I really really want your opinions on this as you are the ones that hear these differences in absolute polarity - please respond.

Where you say "Out of phase will cause loss of bass and accentuated treble in this speaker which is is easily heard.." well when the system is in correct phase, the wilson's midrange will have inverted phase so what happens to the midrange's sound in this situation? Will it cause loss of midrange or accentuated midrange - or just right :)

I do agree with you that I wish the reviewer took more care. I still don't think that the way he set up the phase would an issue, but it would have been best if he just did it the way CJ suggest, then if he still heard the same thing there would be less for us to complain about.

I think it would have been even better if, as soon as he heard something that sounded even remotely wrong with the frequency response, he actually arranged for it to be measured on the preamp itself with a load approximating the amplifier he was using. That way there is no question whether there is a frequency response issue with the tested device or not. If he doesn't have the skill for this, then find someone who does. We should probably question all reviews that fail in this way.


Quote:
Originally Posted by turntable View Post
Plurn, reverse the positive and negative connection on your speaker wire going into the speaker terminals and play some of the same music. Will take you less than one minute. You will easily hear something is wrong.

Cheers

Well - no I won't hear something is wrong. As I mentioned earlier "whether my system is set up phase correct or phase inverted does not change how bright the treble is. It certainly does not make a recording of someone that is breathing out, sound like they are breathing in. It does not even change the soundstage depth or width." I know this because I have tried this test (reversing the wiring at the speaker terminals) many times. Perhaps not valid testing since I have not done this particular test double blind. I have also tried a similar test by swapping the polarity of the signal my dac produces by remote control - this pretty much is a valid blind test because I can rapidly change the polarity multiple times in a way that I lose track and don't know what polarity is set. Then I can swap it instantly as many times as I want for as long as I want with many types of music. No difference detected. Certainly no differences big or obvious that people claim. Measuring the output of the dac with my computer confirms that the polarity changes when the polarity button is pressed.

And before anyone suggests it - no I don't have cloth for ears.

Shane, now that we have worked out your midrange drivers (in your Wilson Maxx 3) are playing in inverted phase, do they sound wrong to you? What about that singer that sounded like he was breathing in when he is supposed to be breathing out when played on an inverted system. You must get that all the time because that is all in the midrange, and your midrange drivers are playing in inverted phase all the time if your system is in correct phase. Sorry - I am being a jerk - I am sure your system sounds awesome. Just trying to make a point.

I guess the point I am making here is that hearing is not just the sound that is produced, it is a complex construction/interpretation by our brains that takes in not just the stimulus of the sound sensed by our ears, but also takes into account biases and expectations and suggestion and other stimulus such as sight, plus a whole lot of other complex processing. Everyone is influenced by these biases - me too.

If you expect correct phase to sound better, and your speakers are wired up so they are apparently in correct phase, it will likely sound better to you. But this may just be the expectation and knowledge that it is in correct phase that is making it sound better to you. If you had no knowledge of phase and did not know if your system was playing in correct or inverted phase, and you listened to it in correct phase and separately in inverted phase, you might not hear any difference at all.

If you expect correct phase to sound better, and you had your system playing in correct phase (or so you thought) but now you learn that it was not actually in correct phase because while the woofers and tweeters were in correct phase, the midrange drivers were in inverted phase - will your system sound worse (to your brain) than it did before you knew this disturbing fact? It might to your brain. Hopefully not though - it is the exact same system it was 20 minutes ago.

If you expect correct phase to not make any difference, then you might not hear any difference when a system is in correct phase or inverted. This could be me. Who can tell. Biases are unavoidable.

Anthony
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  #24  
Old 07-14-2016, 04:06 AM
stereoquest stereoquest is offline
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Plurn,

The polarity of a driver cannot be viewed without looking at the crossover and phase shift within it . With Wilsons when listening on axis the negative polarity of the midrange driver is counter acted by the phase shift of the cross over at its frequency which causes all drivers to be in phase at the specified listening position.........which is why Wilson sets out very specific listening positions for all speaker head unit settings. I am no engineer and do not have the ability to write it as elegantly as it it should or could be written. I think Wilson use the term Time Aligned.

Not all speakers react as clearly to phase shift as the Wilson and this is mostly crossover dependent. Perhaps the words loss of bass and increased treble are over egging it a bit - Wilsons not in phase sound slightly off as do many other speakers.

Better info to be found in books than on the net..any easy read is Robert Harley a guide to high end audio--- it has a section specifically on cross overs and their effects.

Now back to the numpty ET3 reviewer !
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  #25  
Old 07-14-2016, 05:36 AM
stereoquest stereoquest is offline
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So here is my rather crude explanation --A Wilson cross over is second order which will create a 180deg phase lag on the low pass driver compared to the high pass driver. So lets start with the bass driver connected in normal polarity------ the signal goes through it and emerges 180deg out of phase at the mid - in order to counter act this the mid is wired reverse polarity --once the signal has passed through the mid the tweeter sees 180 deg phase lag compared to the mid and is wired the opposite of the mid to correct phase ---so the same as the bass driver (standard polarity ). In the end the Phase remains the same but yes the mid is wired reverse polarity .

hope it makes sense----and hope I got it right !
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  #26  
Old 07-16-2016, 06:24 AM
plurn plurn is offline
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Hi Stereoquest.

Thanks for providing the insight about how crossovers work. I did some research around what you wrote and while I did not follow all of what they were saying they do seem to indicate that what you write is correct for some speakers - I think - it is not always clear what they are getting at.

For the Wilson Maxx 3 example we were using, reading the stereophile review does not seem to match up with what you are saying. Though I might be misunderstanding them. They show a step response (which is measured with a microphone at some point in front of the speaker), and they explain that the step response shows a positive initial response from the tweeter, and negative initial response from the midrange, and a positive initial response from the woofer. So whatever is happening with the crossover or the wiring of the midrange driver, the end result (for the listener/microphone) is that the microphone is picking up that the sound from the midrange is in inverted phase to the other drivers. Or is it. I am not sure - read on.

There is another stereophile article that on page three of the article expands on how step response is measured and shows measurements for different speaker system examples: http://www.stereophile.com/content/measuring-loudspeakers-part-two-page-3

To me the second speaker they use as an example has similarities to the way the Maxx 3 is set up, and they show measurements in a similar way with the midrange having an initial negative response, yet at the end they have this conclusion which seems to agree with what you said:

"It appears that the designer of the speaker featured in these four graphs has chosen to use high-order crossover filters of some kind, which necessarily introduce significant (180 degrees or greater) phase shift in the crossover region. To this must be added the phase shift due to the time delay between the units, and the additional 180 degrees phase shift due to the inversion of the midrange's electrical polarity."

I read that as the midrange being about 360 degrees (maybe a little more) different to the other drivers, so basically in phase with the other drivers as you indicated. That seems to conflict with the measurements taken by the microphone. I would think the microphone should show the initial response of each driver to be positive yet it doesn't, the initial response of the midrange driver is negative. So I really don't know - consider me confused.

Back to the ET3 reviewer - um there has been some extra comments on the review.

Anthony
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  #27  
Old 07-16-2016, 10:50 AM
stereoquest stereoquest is offline
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Hi Plurn ,

I am no engineer and am wrong sometimes but have a fair grasp of what is superficially going on.

I was referring to Wilsons as a whole but the maxx 3 is no different .

Things to remember with stepped response -

Time frame is milliseconds --- 1000th of a second.

The initial midrange response is negative but driving positively for the rest .

It is for the first 2 10 thousandths of a second or so .....which is a very very very short period of time .This to me just shows phase correction through the crossover and represents as a slight delay ---

Using your stereophile example the bottom line mentioned by JA is :

The result is an on-axis amplitude response in which the drive-units add in-phase to give (we hope) a flat response.

Perhaps a peace offering to Turntable is required 😇
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  #28  
Old 07-24-2016, 01:03 AM
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Littlebunny Littlebunny is offline
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I thought I should chime in here as a prior owner of the ET-3 and upgraded ET-3 SE. I unfortunately have to concur with the reviewer's findings regarding the ET-3's sound, less so with the ET-3 SE, which wasn't under review anyway. I just couldn't get the ET-3 to work with my system so I had to part with it. I've since settled with a 2a3 SET system. I also had some issues with the ET-3 being hard on the 6922 tubes it used necessitating frequent replacements. A tube supplier mentioned to me that some customers had problems like that with the ET-3.

Anyway, I don't think the reviewer's impressions were out-of-line. I thought the ET-3 strange sounding (it replaced a McIntosh c220 preamp), but I couldn't put my finger on exactly why it did at the time. Just my personal opinion.
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