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rplace

REW Generator

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Calling all the usual suspects @Chris A @Coytee @mark1101 @Khornukopia @babadono please add others I've missed.

 

I'm back to trying my hand and 2-way active/Xilica/REW learning and spent about 45 minutes scratching my head and can't come up with a valid reason for this. REW has a generator that I use to, among other things, create pink noise so I can level my HF and LF. Chris has taught us all well that we only mess with one speaker at a time....but often I'll have both of my mono blocks and both channels of the LF amp turned on so when I am done measuring and tweaking they are ready to listen to.

 

For this problem it does not seem to matter if I am dealing with the HF or LF but when I use the Generator I'll typically select the "left" or "right" speaker I'm dealing with not the "both" option....see below. All good, right?

 

If I have all amps turned on and the various channels (Right LF, Left LF, Right HF, Right LF) NOT muted and I play the generator on Left speaker only I still get noise through the Right speaker. Likewise if I have Right selected in generator I get noise in the Left speaker. The really bazar thing is that if, say I'm tying to manage the Left speaker I actually get more (louder) noise from selecting Right or Both than if I select Left from the generator. I figured I had the Xilica mixer messed up or my cables form Xilica to Amp. Double and triple checked. I'm 99.9999999% positive all my cables are correct and my Xilica settings are right. I'm using a Windows laptop with built in sound card. I have a cable with a mini stereo jack on the laptop end and a red/white RCA jack on the other ends hooked up to Passive Pre (volume control) that in turn feeds the Xilica Channel 1 and 2 in which maps to the correct 4 channels of amplification to do RTHF, LTHF, RTLF and LTLF. I tried a different mini headphone jack out that has RCA female ends on it and RCA Male/Male cables to the Pre's inputs as well.

 

WTF? I'm thinking it almost has to be REW. Can anyone else confirm similar behavior or ideas where else I need to check in my system, Xilica or REW? In order to get around this I'm using the Xilica to Mute input and output to all the channels except the one I am matching Gain on or taking measurements on. How on earth can I be selecting "left" in the screen shot below and getting noise in both left and right speakers???

 

REWGenerator.JPG.39aba61a69ed83c472a488dcbab029af.JPG

 

Cable examples:

4408001_sd.jpg;maxHeight=640;maxWidth=55

 

 

 

e89a66b44cc60eae70a45f7bf26dc03a_1024x10

 

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Hmmmmm....doesn't make whole lotta sense. I spent a bunch of time with my laptop settings getting the L and R output levels to be equal when the REW generator was being used AND then came to the stark realization I would only be doing one channel at a time most of the time! So I am just going to use one of the outputs first plugged into the L channel then move that same output over to the R channel and proceed. That is what I also suggest that you try. Plug one of the outputs, as far as i know it doesn't matter which, into your left input and plug a dummy plug into the right input. You should then have absolutely no signal on the right. If you still have something on the right there is something else wrong going on. But if all is well proceed with getting the left channel set. Then switch the REW output over to the right input and put the dummy on the left. Now only the right should have signal. Proceed with getting the right channel set.

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BTW do you have "REW 101" pdf. It's to big to attach here.

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When you play some music from your laptop thru this cable into your stereo, do you get normal left and right sounds?

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If yes, then it may be that the REW software is trying to output an HDMI signal path into the 2 channel of your laptop, and so the left and right are getting mixed together?

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21 minutes ago, babadono said:

BTW do you have "REW 101" pdf. It's to big to attach here.

 

No I do not, did not know it existed. I'll look into it.

 

14 minutes ago, Khornukopia said:

When you play some music from your laptop thru this cable into your stereo, do you get normal left and right sounds?

2 minutes ago, Khornukopia said:

If yes, then it may be that the REW software is trying to output an HDMI signal path into the 2 channel of your laptop, and so the left and right are getting mixed together?

 

I've not played any music from the laptop but that is a good idea. I'm an all vinyl guy so one source (turntable) in that room for music. I disconnect the phono's R/L in order to hook that mini-jack RCA thing into where the phono previously was. This gives me Laptop>>cable>>Volume control>>Xilica.

 

Guess I could shut down REW to remove that from the equation and play with the Right/Left of the Windows or Sound Card mixer.

 

@babadono I believe in the past, because I was always doing one speaker, I simply had the Mini-Jack-RCA cable with one RCA connected to Left in and the other not connected at all. So I can't really say if this is something new on my end. My plan this time around was to actually take Right and Left measurements not just copy one sides settings to the other.

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1 hour ago, rplace said:
5 minutes ago, rplace said:

I disconnect the phono's R/L in order to hook that mini-jack RCA thing into where the phono previously was.

 

 red/white RCA jack on the other ends hooked up to Passive Pre (volume control)

 

So you are unplugging your phono and its pre-amp from your Passive Pre?

 

11 minutes ago, rplace said:

I've not played any music from the laptop but that is a good idea.

 

Just search for a song and try some free online music.

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FWIW just playing some music and making the judgement "yes it sounds OK" does not prove that only left channel information is getting to the left and right to the right.

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That is true. So the test on a laptop is to go to Settings, Sound, Device Properties, Advanced, and click on TEST. That should output a short Left to Right jingle. 

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I do something similar, but all via USB to a single laptop.  I use a USB out of laptop to send the generator signal to my system (to my Benchmark DAC).  Use a USB mic into laptop to capture the readings and view. Use another USB to Xilica and use Xconsole to mute channels not being measured and to make adjustments to Xilica.  This setup allows me to change settings on the fly and see the results / make adjustments in real time.  Very handy.

 

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2 hours ago, Khornukopia said:

 

So you are unplugging your phono and its pre-amp from your Passive Pre?

 

 

Just search for a song and try some free online music.

 

 

Forget the phono/pre or turntable (it is all external to this - TT, MC cartridge, Phono pre are all disconnected). I have one source, the laptop. The laptop connects to the passive preamp which has a single function, to be volume control. So no active preamp, nothing surrounding vinyl or TT. Just a laptop to send noise to Xilica via REW and REW to measure things. The same laptop in turn can be used to change things in Xilica via XConsole.

 

You would think music on laptop is a simple thing but I live in the one place on earth that does not have internet access, at least not easily. I'll be able later to hook laptop back up and play with a .wav file or windows mixer controls to take REW out of the mix. I just find it very odd that REW would have right/left/both settings for that generator that in turn do not work.

 

It is easy to mute inputs/outputs for Xilica and make only one channel work for sweeps, testing, etc....but the bigger question I have is what if things are truly going to both channels when they should not be. I can't see how that is possible given my verified connections and Xilica settings. I've googled REW Generator Right/Left not work and many variants. No luck. I'd think if it was REW I would not be the first to discover. I'm guessing my sound card configuration or similar. No time to check right now with work. Figured somebody out there would know or hook up their REW/Laptop and see if Left or Right plays on both and if Both is actually louder on one channel with the rest disabled. Very puzzling, makes not sense to me at all.

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I can hook it up tonight/tomorrow, I'm not home right now either.  You did understand my suggestion of using just one output, first to the left input then to the right to make sure there is nothing else in your system mixing the signals?

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5 minutes ago, babadono said:

I can hook it up tonight/tomorrow, I'm not home right now either.  You did understand my suggestion of using just one output, first to the left input then to the right to make sure there is nothing else in your system mixing the signals?

 

Yes, I did and I'll try that when I get a .wav/.mp3 file and my laptop and things hooked back up as well.

 

Thanks!

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So the plot thickens. Here is what I can report back and my thoughts on each.

  1. If I plug a set of headphones into Windows laptop and run REW Generator only Left....noise out of left headphone only. If right, right only, if both both - Seems like REW is good
  2. If I play music in Headphones sounds normal, whatever normal means - All good
  3. If I try the windows speaker test (see screen shot below) via the laptop's speakers or headphones it plays left first then right (yellow highlighting in screen capture below - All good
  4. If I hook up laptop to passive pre in, as I do for REW/Xilica work AND play the windows speaker test I first get LOUD noise through RIGHT speaker and faint sound through left next I get faint sound through right and Loud through the Left. - This cannot be good. First the Left/Right is backwards and the faint sound is through the opposite.

This seems consistent with REW having louder noise when both are selected and fainter sound on the selected speaker when only one selected; that is Left faint when Left selected in REW or Right faint when Right selected with the non selected speaker being louder.

 

Reasonably sure I have a problem with Xilica configuration or my cabling, but for the life of me I can't figure out what it is.

 

Oh, crap forgot to try @babadono idea of only one connected and seeing if noise through both. I'll get on that next.

 

Where to check in Xilica, the mixer right? See 2nd image below for some of the Xilica settings:

  • 1 in = Right In
  • 2 in = Left in
     
  • 1 out = Right LF out
  • 2 out = Left LF out
  • 3 out = Right HF out
  • 4 out = Left HF out

WindowsTest.JPG.14851f923a7bc5ace759e124db111598.JPG

 

XilicaSettings.thumb.JPG.3c2849f722a66e9ac5a22c234485f54e.JPG

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To answer @babadono question. If I only hook up the right input (that is the right/red wire) between the laptop and the Pre's Right In and the left/white wire is disconnected. Nothing is connected to the Pre's Left In. When I select the Right speaker only via REW's Generator I get noise from the right HF and LF. When I switch from REW's Right to Left the sound only comes out of the Right size but it is a LOT louder. If I select both it is also louder than Right only. This does not seem right.

 

Same thing happens when Left input only is connected and the Right input is disconnected on the pre amp. If Left selected in REW; sound only form left HF and LF. If Right or Both is selected in REW the volume is a lot louder and only from the Left HF/LF.

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7 hours ago, rplace said:
  • If I plug a set of headphones into Windows laptop and run REW Generator only Left....noise out of left headphone only. If right, right only, if both both - Seems like REW is good
  •  
  • If I hook up laptop to passive pre in...     the Left/Right is backwards and the faint sound is through the opposite.

 

Have you tried a different connector cable?

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6 hours ago, Khornukopia said:

 

Have you tried a different connector cable?

 

Yes, see the first post.

 

Update: I'm back to thinking it is REW, well not directly. When playing the windows test sounds on my laptop I though I could hear nose from Left when Right should be playing and vise versa. Hard to really tell but faint noise when holding laptops speakers directly to my ear. So this morning I put the headphones back on....but only the opposite ear of which should be playing. The noise is there in both windows test and REW. So I found this silly video on YouTube https://youtu.be/6TWJaFD6R2s

 

Sure enough when the left speakers is "playing" I get slight music from Right headphone same for the other when it switches. As a reality check can someone give that a go with speakers or headphones and report back if anything plays in opposite speaker. I'm starting to think something with my laptop/soundcard/drivers....but that seems like a long shot at best.

 

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If you had decent connectivity... I'd say try burning an Ubuntu image to a thumb drive and boot the laptop into GNU/Linux off of it.  Sure sounds like a driver/O.S. problem to me, and a completely different operating environment would rule it in or out.

 

Either that or some crud in the output Jack is preventing a good "common" connection.  And/or for whatever other reason your plug isn't seating fully?

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I believe it is called crosstalk. Most amps have some, unless they are two circuits for the whole path. Are you sure that isn't what is happening?

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8 minutes ago, glens said:

If you had decent connectivity... I'd say try burning an Ubuntu image to a thumb drive and boot the laptop into GNU/Linux off of it.  Sure sounds like a driver/O.S. problem to me, and a completely different operating environment would rule it in or out.

 

Either that or some crud in the output Jack is preventing a good "common" connection.  And/or for whatever other reason your plug isn't seating fully?

 

This morning after fighting with headphones and grasping at straws for both cables and sound card I dragged out an old laptop with Win7. Tried the test tone from Windows. Same problem faint noise in opposite headphone. Downloaded and installed REW same thing. Next I found this site https://www.audiocheck.net/audiotests_stereo.php with a very distinctive Left/Right/Both sound and played it on both laptops and hear sound in opposite ear. I'm using Klipsch Reference on ear headphones with the Klipsch supplied cable (not Bluetooth). It is minijack on the source side (laptop, phone, etc) but even smaller where it plugs into the actual headphones.

 

So to eliminate windows all together I connected the Klipsch headphones to my Android phone and tried the same link above. If I have the volume turned up about 3/4 of the way, put the headphone only on my right ear, cover the left headphone up with my hand and play the left tone I hear very distinctively "Left Channel" in an English voice on the right site headphone. Now if I have both headphones on as a normal person would if I play the left tone it sounds like only from the left site. Likewise, if I play right tone it only seems to come form right side. But when the volume is turned up reasonably high and you have the opposite headphone muffled you can clearly here Left tone in Right headphone or Right Tone in Left Headphone.

 

I'm losing my mind here, any ideas at all? I'm charging up the headphones to try Bluetooth and eliminate cable as well as digging through drawers looking for cheap ear buds.

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