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Driving Avantone Mixcube via Apogee Duet2 Stereo Headphone Out?

Discussion in 'Monitoring / Headphones' started by BassJumper, Jul 26, 2012.

  1. BassJumper

    BassJumper Active Member

    Hi, I just registered and figured I'd jump in with a tech question. I hope to learn a lot from all of you and maybe even be able to contribute at some point howdy

    I've been reading Apogee Duet2 interface which has a sum-to-mono feature that can be activated via a soft-button and applied to the main outs or the stereo headphone output. I'd like to connect the Duet2's stereo headphone output to the MixCube's input (it has a combo TRS/XLR input). I'm looking for advice on the best cabling option.

    Apogee support said "Yes, you can sum the output to mono and use just a standard trs to xlr cable to the cube." But then I Googled the Rane Why Not Wye? article and figured I'd better ask those in the know. An option mentioned in the Mixing Secrets book is a custom cable using resistors to sum the left/right stereo channels, thus avoiding having the L/R outputs see each other impedance-wise. One concern I had was if I unintentionally disengaged the sum-to-mono feature, would that cause any issues?

    Thanks in advance and sure glad to be a member here,
    Steve
     
  2. Boswell

    Boswell Moderator Distinguished Member

    Hi and welcome!

    Do you really mean using only one Mixcube monitor for mono monitoring and not a pair of them being fed the same signal?

    You need to take one thing into account if you are considering using the headphone jack as a line output, and that is that headphone jacks are unbalanced stereo and not balanced mono. This means that a single jack has connections for both the left and right channels plus the ground as a return. A balanced jack carries only one channel in positive and negative phase plus the ground. If you were to use a TRS jack lead to connect the headphone output to the Mixcube's balanced input, you wouldn't do any damage, but you would not get much sound out. The Mixcube would amplify the difference between L and R channels in the source, which, if summed to mono in the Duet2, would be small and tizzy.

    The Duet2 headphone output can be used, but you need something like an insert cable to split the L and R components. You would plug the TRS end of the insert cable into the Duet2's headphone output and one or both of the TS ends of the cable into one or two Mixcube boxes.

    A better scheme is to use the Duet2 break-out cable, as it has two jack sockets that are true balanced. My guess is that the Apogee support folks were referring to taking a balanced TRS output from there into your Mixcube rather than using the headphone output. The break-out cable route works with TRS jack leads, and by using two TRS cables you can take both L and R outputs to a pair of Mixcubes if you wish.
     
  3. BassJumper

    BassJumper Active Member

    Hi Boswell:

    My bad, I should have clarified that I plan on hooking up only a single MixCube for mono monitoring purposes. I'm currently using the Duet2's stereo line out pair to drive a pair of active audioengine a5 speakers. I know, probably not the best solution for near-field monitoring, but that's another problem for another day.

    So the headphone output of the Duet2 seemed to be the obvious choice for connecting to a single MixCube. I figured it would also allow me to easily switch back and forth between headphone monitoring/mixing and mono monitoring/mixing. I was started down the path of constructing a custom cable using resistors to sum the left/right stereo channels, but once I saw that the Duet2 had a sum-to-mono feature, I chatted Apogee tech support to see if there might be a simpler cabling solution. And they said "Yes, you can sum the output to mono and use just a standard trs to xlr cable to the cube."

    I'm not sure if/how this updated info (i.e. single MixCube) affects your suggestions?
     
  4. Boswell

    Boswell Moderator Distinguished Member

    No, they're still talking about using the separate line outputs. If you want to use the headphone jack, just get an insert cable. Connect the cable's TRS plug into the Duet2's headphone jack and one of the cable's TS plugs into the Mixcube combi connector and set the Duet2 to sum L+R to mono. Tape up the unused TS plug to avoid short circuits to other metallic objects.
     
  5. RemyRAD

    RemyRAD Well-Known Member

    Don't be so cheap. Get yourself a second mix cube. It's an alternate monitor that's quite worthy to have two . Then you use the sum to Mono in your Apogee annual be monitoring in Mono from both mix cubes a.k.a. dual channel mono. The only time you'd want a single mix cube for Mono might be in a 5.1 surround system where you want a center mono mostly dialogue channel speaker.

    Mono doesn't necessarily mean a single speaker. But a signal being fed to 2 speakers that has been converted to mono within your software or the computer audio interface device. When you wear a pair of headphones and are listening to a Mono vocal track for instance, it is playing into both headphone channels so you hear it with both of your ears. It would be obnoxious coming into just one ear (except for those studio singers and musicians that are having pitch issues were you tell them to take off one ear of their headphones).

    Conversely, if you happen to be deaf in one ear, you never need stereo as it will be imperceptible on the wrong side of your brain. You know the side that is awake. Heck, I'm not even sure which side of my brain is awake? Since both sides seemed to be damaged? But I'm still listening to things in stereo and in Mono when I press the mono button. LOL In fact neither side of my brain may actually be fully awake? So maybe we should hold a wake for both dead sides of my brain? Maybe each side is equally dead as the other? Which might explain why I get so many things right with audio even though I'm more of a leftist?

    You might also want to vote for Barack Obama as opposed to Romney since Romney wasn't sure that the folks on the east side of the Atlantic where is well-prepared as the folks on the left side of the Atlantic LOL. Romney is obviously something of a monaural non-thinker and Barack Obama appears to be more well centered in his left-right imaging. LMAO. You never want to jerk around with your audio like Romney did the other day in the UK because it's not OK in the UK to be so off centered. And I think Barack is a much better singer than Romney? He does a good rendition of Marvin Gaye even though Barack Obama is not gay. And Romney does not believe in anything gay which means he also does not understand humor and has virtually no humility or is that humanity? And on the Fox network Sean Hannity has no humanity. That along with Bill O'Reilly that only knows how to get people riled up so maybe he should change his name to Bill O' Riled? Reilly now I am being quite serious because you never want to just Romney away from your problems.

    I vote Democrap since I recorded a lot of demo crap, throughout my career.
    Mx. Remy Ann David
     
  6. gdoubleyou

    gdoubleyou Well-Known Member

    No wake needed, I pronounce your brains alive and well!
     
  7. RemyRAD

    RemyRAD Well-Known Member

    I'm cured! Even though I didn't go to GW but instead went to George's Town in Georgetown at Georgetown, in Georgetown which is a great District of Colombia to be in even though it's not in Colombia but a different District of Columbia. Wait a minute! You are confusing my damaged brain. And that's not so cool to be cruel to someone who needs to be cool because of all of the record heat which ain't cool. Gee... W. I think you have exacerbated my brain? Is that an incomplete sentence?

    I'm good at patching but I have no idea where these synapses all go?
    Mx. Remy Ann David
     
  8. BassJumper

    BassJumper Active Member

    Thanks RemyRAD, I just ordered a "pair" of Avantone active MixCubes. I assume Boswell's suggestion of using an insert cable still applies with a TS lead going to each of the MixCube speakers, and then activating the sum-to-mono option on the Apogee Duet2 interface. I've read that one of the many advantages to spending some time mixing in mono on single-driver speakers is the lack of a crossover network and the associated phase-related anomalies in the critical mid-range audio region. Maybe this is something that I'll pick up on after getting accustomed to mixing in mono.

    Thanks for the suggestions, Steve
     
  9. RemyRAD

    RemyRAD Well-Known Member

    Boswell is usually right in all of his suggestions. I've always been impressed with his superb British accuracy.

    There is much to be said for single point source monitors and also mixing in Mono. There are very few professional studio monitors that I find tolerable as single point sources. Many of us grew up utilizing the Altec Lansing 604 E monitors. This was a 15 inch diameter low frequency driver with a high-frequency driver mounted through the middle of the low frequency driver. Those were popular from the mid-1950s. You still find some of those in quite a few control rooms today as a more modern release that was slightly modified by UREI. Which was Bill Putnam's company and before that by Doug Sax from the Mastering Lab. They both offered up greatly improved passive crossover networks and a modified horn that relieved some of the honk. High-frequency horn loaded drivers were quite popular on the larger far field monitor speakers of the day. Though lots of folks like myself never cared for that sound of the horn. Universal Recording Electronics Inc. also included extra time alignment through their passive crossovers and better cabinets. The original classic was then rebranded as the model by Doug Sax known as " Big Reds " and the UREI model number 811 followed by another one with an additional 15 inch low-frequency driver known as the model 813 and then the model 815 with dual low-frequency drivers. A smaller model was also introduced known as the 809 with a 12 inch diameter.

    These eliminated the spatial timing anomalies from multiple drivers arranged willy-nilly in the boxes. The British speaker manufacturer TANNOY also offered a similarly designed single point full range control room monitor line that were also quite popular. The problem with all of these particular monitors however was the long throated horn of the high-frequency driver whose voice coil mechanism was behind the magnet structure of low-frequency driver. Kind of like passing sound through a paper towel cardboard tube only worse. But there were reasons for keeping the high-frequency driver voice coil slightly behind that of the low-frequency driver. But you don't get something for nothing. Most purists realized that direct radiating drivers were more ideally suited to better sound. But then there were problems with time alignment again. And that's why you find some audiophile speakers with staggered midrange and high-frequency drivers to correct for these timing errors. And that's why a single little 4 inch driver offers up an advantage. They have no timing errors. They generally also represent speakers closer to that which much of the listening public listens to stuff through. Coupled with a quality amplifier it makes for a great reference source. Because of it sounds good on one of those you pretty well will know it'll sound good on most everything else of any size or type.

    When it comes to monitoring in Mono, you'll know pretty quickly if you've got any phase issues going on. It used to be a prerequisite to do so in the days of cutting to vinyl. You can't have too much out of phase material, no matter how cool it might sound, without the cutter head leaping out of the lacquer master disk. He was also a good way to make sure that your AM radio mix would sound great. And also your television mix since TV did not go stereo until I put it on the air in 1984. I actually was monitoring television at home since 1981 from my first-generation Mono VHS VCR into my DYNACO amplifier and JBL 4311's in my living room. I had been checking my stereo mixes in Mono since 1973. So I am largely a monophonic engineer even though I have started stereo recording by the late 1960s.

    In 1970, I miss wired my SHURE M-77 phonograph cartridge out of phase. And when listening to the first Santana Columbia records Abraxsis release and pushing my mono button, I heard a third channel! I thought this was pretty cool at 14 years of age. So then I fixed that wiring and took a third speaker and connected across both left and right positive terminals of my amplifier. It was a Sony amplifier and luckily, I didn't blow it up. But now I had three channels of speakers! And most of that stuff was reverb I was hearing along with a few other instruments that were not prominent in the stereo mix. I thought I was pretty smart. So then I hooked up a fourth speaker to the third speaker out of phase to the third speaker and I was enjoying surroundsound at 14 in early 1970. It wasn't until I was 15 and I heard about this guy by the name of David Hafler who made kit amplifiers and he was offering one with a special quadraphonic circuit on just a stereo amplifier. I got that for my birthday and was rather disappointed to find out my circuit was in his amplifier kit. But I used that amplifier kit for the next five years never bothering to hook up my four speakers again. But I did graduate to his A 25 pair of loudspeakers. I actually prefer two way speakers over three-way but have been using JBL 4310/11/12's ever since then. I still long for a single point full range speaker that could cut the mustard for control room monitoring purposes. The British Quad Electrostatic speakers I had considered for my control room 21 years ago. But they can't handle any power in the control room environment. So we all have to just jump around thinking we have the best loudspeakers. Blah... so where is modern science when we need it? We're still monitoring with 1950s era speakers. And no one has yet come up with what I really want to hear.

    By the way, for the past nearly 10 years I've been utilizing the FOSTEX 6301's self powered monitors. 4 inch driver 10 W amplifier. Nice little references.

    I'm still trying to conceive of something to fill that single point full range bill.
    Mx. Remy Ann David
     
  10. RemyRAD

    RemyRAD Well-Known Member

    Oh yeah I also had AURA TONES in my control room since 1978. Nice with a Crown D-60. Nicer than my 6301's but not as portable or convenient.

    Remember those 6 x 9 car speakers with the metal WIZZER cone add-on in the center of the speaker? UGH!
    Mx. Remy Ann David
     
  11. Boswell

    Boswell Moderator Distinguished Member

    Yes, the insert cable will translate the L,R configuration of the headphone connector to the 2x mono jacks to mate with the combo connectors on the Mixcubes. Just by operating the stereo/mono touchpad on the top panel of the Duet2 you will be able to switch the Mixcubes from stereo to dual mono. The same can be made to happen, of course, on your main Audioengine A5 monitors connected to the Mixcube's TRS line outs, as the summing control can apply to headphone out, line outs or both.

    Use of single-driver loudspeakers that don't need a crossover network is a totally different thing from mono/stereo monitoring. Passive networks that operate at loudspeaker power levels do indeed tend to have both phase and impedance issues, and that's why most of the high-quality PA loudspeakers and studio monitoring systems have line-level crossovers and separate power amps for each of the different drivers in the loudspeaker cabinet. With an analog line-level or a digital crossover unit, you can generate linear-phase splits that avoid the gross phase excursions in the crossover frequency region.

    The other factor you have to consider is the amount of on-axis power delivered as you go through the crossover region. A poorly-specified crossover network will not roll-off enough amplitude to one speaker of the pair or group in a cabinet before handing over to the next higher/lower one, resulting in "bumps" in the power output response of the full cabinet. Linkwitz-Riley filters overcome this problem, and here's a Rane note on Linkwitz-Riley crossovers.
     
  12. BassJumper

    BassJumper Active Member

    Yup, but for some reason, I recall them being marketed as tri-axial speakers or maybe I'm confusing that with something else. I remember installing a pair in the back of my brand new 1976 Chevy Nova; power blue with the cheapest pie-plate push-on hub caps the world has ever known :biggrin: The scary part was cutting the 6x9 holes in the back panel. The fancy plastic speaker grills didn't take but one summer to warp like hell. Growing up on the east coast in the tri-state area, I purchased them at the now infamous Crazy Eddie's. His prices were insaaane!!!
     

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