Another phase question with subwoofer connection

[bartonfields]

Hi Guys, long time CJ owner but new to the forum, hoping someone can give me some advice.

I have an ET6 pre amp and Premier 11 power amp and have my speaker cables on the P11 reversed to correct the phase inversion.

I have ordered an REL S/812 subwoofer and have asked REL support for advice on where to connect the neutrik red, yellow and black cables, when correcting phase. This was their response…

“If the amp is complete reverse phase, then its going to be the same as the amp - so in this case red and yellow will go to speaker negative instead of positive, as you suggest with your speakers. This leaves our black cable ( which is ground). If the speaker positive is ground - then this is where you should connect, but if there is any doubt, then look for an alternative ground such as a ground post or a chassis screw.”

So what I need to know Is whether the speaker positive on the Premier 11 is connected to ground or not? Any ideas?

Thanks

[AnotherJohnson]

I just read the REL S/812 manual.

https://rel.net/wp-content/uploads/2019 ... -02-20.pdf

I think their simplicity is inordinately complex, but that’s neither here nor there. It did make me appreciate the nice binding posts, as well as XLR and RCA input choices on the Martin Logan BF210/212 series.

The (-) is ground on the amp.

If it were me, I’d call conrad-Johnson about using the REL. it might save you some aggravation.

Or perhaps there is a REL forum where someone knows.

You could just hook it up + to + and - to - , invert at your speakers by reversing the leads, and reverse the sub by setting it 180 degrees out with the switch.

I note that REL’s advice about initial sub placement is the same as Martin Logan’s. That worked out ok in one of my applications, but not in the two most recent. So be aware of that as you’re trying to dial in the phase angle.

[admin]

Agree, hook up the sub just as it shows in the top figure of page 14 of the manual. Then shift the phase switch to 180.

[bartonfields]

Yes I did wonder about connecting as normal and using the phase at 180. The REL guy didn’t suggest it, but it makes sense. Thanks guys.

[AnotherJohnson]

The issue is that the CJ amp is NOT inverting. It’s the preamp that inverts.

The speakers are unpowered, so they float and don’t know one ground from the other.

But the REL is powered and will ground the same as your amp at the mains. So … if you do what REL suggested without confirming that the CJ amp is indeed backwards, (which it isn’t), you will establish a world class ground loop at the least, pop some fuses perchance, and if very unlucky, let the smoke escape from parts of your system. Once you’ve got a smoke leak, you’re generally screwed.

I could be wrong. I’ve not studied or used REL subs, although I know they are well thought of.

But I would be really leery of connecting the hot side of one amp to the cold side of another.

I expect that Roberto will know and, of course, I am reassured that admin and I are one the same page.

[bartonfields]

I’m running a hybrid system, both home theatre and 2 channel stereo. The CJ ET6 and P11 are driving my main LR speakers I’m using a Lyngdorf MP40 for Home theatre processing connected to other amps for driving surrounds. I chose the REL because I can run both the High level connection for 2 channel listening and the LFE.1 for home theatre LFE effects at the same time.

I certainly don’t want to risk blowing anything, so until I can workout how to connect the neutrik correctly, I’m only going to use the sub for home theatre duties utilising the LFE/XLR connection. My previous sub was only ever connected via the Low level connection directly from my processor.

I’ll contact CJ and ask their advice too, but if anyone else can shine a light on this issue it’ll be much appreciated, but I’m inclined to agree with you guys.

[admin]

What do you fear would cause a problem? If the REL is simply in between the amp and the speaker. It's functioning as a simple passthrough with a low pass filter. Most subs do this by simply having a set of input and output speaker terminals. The REL is fancy with their proprietary connector but it's doing the same thing.

[AnotherJohnson]

I wasn’t clear. I agree with admin. Top figure of page 14 and 180 out.

There’s no danger if you do this.

It’s in parallel with the speakers, but the input impedance is so large, it doesn’t load the main amp.

[bartonfields]

Apologies for the confusion, Thanks Guys, I’ll give it a go next week, as I’m away for a few days now.

[admin]

BTW- If you want to upgrade the REL sub connection cable, one of my favorite cable companies offers these at a reasonable price. You can get the cable length and terminations to custom spec. They are made in the US, have a lifetime warranty, and a 30 day money back guarantee trial period.

Here is the link: http://signalcable.com/relspeakon.html

[WPG]

I have had a REL Q100E subwoofer in my system since 1997, so keep in mind my experience with my 25 yr old REL sub might not be relevant to the OP’s new subwoofer and his system.

It’s my understanding whether you set a subwoofer in phase or out of phase with your main speakers will depend on your personal preference. Hopefully there are no technical reasons why CJ may not want their equipment running with an out of phase subwoofer since I have been doing it for years.

The Q100E does have a phase reversal switch; position 1 is the positive phase and position 2 is inverted. The instructions in the owner’s manual for setting the phase reversal switch says to “Listen to the quality of the bass with the phase switch in position 1 and then in position 2. Choose the position which subjectively offers the tightest and cleanest bass.” The older Q100E manual is asking you to look for the phase that “offers the tightest and cleanest bass” the newer REL Series S manual is asking for you to look for the “loudest or fullest” regardless whether the subwoofer is in phase or out of phase. Ever since I got my Q100E, whenever I made noticeable changes to my system I would experimented with the phase reversal switch along with the filter control to see what sounded best to my ears.

Through the years I have run my REL sub both in phase and out of phase with my main speakers with good results using a PV15 and an ET5 (both are phase inverting) however I have always used them with solid state power amps which may or may not be a factor. In 2007 I added the PV15 to my system that was set up for surround sound and 2 channel stereo with Sonus Faber speakers and the Q100E. Unfortunately, I don’t recall what phase I had set on the REL at the time.

My current system is 2 channel stereo only with my ET5 preamp, a Belles 350A Reference Power Amp, Salk Veracity HT2-TL speakers and the Q100E. The ET5 is the only phase inverted component in my system; my phase switch has been in position 1 (positive phase); and I have been happy running the subwoofer out of phase with my main speakers for years until some recent system changes.

I recently upgraded my main speaker cables, the REL Neutrik Speakon cable, added a DAC and have done some tube rolling with the ET5 which have made some big improvements to my system. The improvements now have me playing with the phase switch and filter control on the Q100E again and I now prefer to have the sub in phase with my main speakers. Provided having the subwoofer in phase with my main speakers doesn’t cause fatigue or other bass related issues after hours of listening I will keep the sub in phase with my main speakers.

Provided that there are no issues running your stereo components with a subwoofer that is out of phase with your main speakers, I would suggest experimenting to see what you like and what works best in your current set up. Then as you make changes to your system or your space, check to see if your phase preference for your subwoofer has changed. It boils down to what you think sounds best.

The upgraded REL cable that I am using is the Reference REL Subwoofer Cable – 48 SSI Wires cable from Morrow Audio. Here is a link if anyone is interested. BTW, Morrow Audio is currently is having a pretty good sale with a 40% - 50% discount depending on what level of cables you buy.

https://www.morrowaudio.com/collections ... le-upgrade

[admin]

The only concern I would have with running a sub out of phase is that it has the possibility of canceling out the low frequencies of full range speakers. Two out of phase waves of the same frequency and location will cancel.

[WPG]

The possibility of cancellation at is true. That is why REL and others recommend experimenting.

In my case, I do not have a dedicated listening room; my system is in my main living area. I do not use base traps or room treatments and I do not have the luxury of placing speakers out into the room. When I was running the subwoofer out of phase, I was using AudioQuest Bedrock speaker cables which are good cables for the money that provided a strong bass.

I do not like a lot of bass; I find too much bass fatiguing. My sub is along the front wall next to my left floor standing speaker and I always suspected that there were may have been some slight cancellation in my set up however I did not have a way to take any measurements. I found the bass to my liking with the sub out of phase when dialed in with the Salk speakers and Bedrock cables.

I recently changed out the AudioQuest Bedrock speaker cables for Morrow Audio SP6 -768 SSI speaker cables which was a major upgrade over the Bedrock cables. The SP6 cables are much more detailed, better sound stage and has a rich full bass. The new SP6 cables give me the ability to dial in my REL when in phase without causing any fatigue.

[admin]

At the end of the day, the only measurement that matters is your ears. If it sounds good to you, done. Not having a dedicated listening room makes setup significantly harder, but not impossible.

If you are looking for a more formal way to evaluate how the sub melds with your main speakers, I highly recommend getting a calibration mic and using software (such as REW). It's not the end all of speaker setup, but it's a good starting point and can help with figuring out if there is frequency cancelations going on due to phase discrepancy.

I recommend this as it is inexpensive but works well: https://www.minidsp.com/products/acoust ... ent/umik-1

[WPG]

Admin,

Thanks for the advice and recommendation. I will look into it.

[hoodjem]

Hello all,
I am not a present CJ owner, but I am seriously considering switching my preamp to CJ Premier 16 or Premier 17.
(I presently use a JRDG Consonance.)

My question has to do with the phase inversion of the CJ preamp's output signal. All the reviews I have read say to just reverse the leads at the speakers inputs in order to correct the phase.

Presently, I take the output from my preamp's RCA ouput jacks and run it into my ML Depth subwoofer using the low-level RCA connectors. Then the sub's high pass crossover outputs (also RCA jacks) that signal to my power amp, which is of course connected to my ML CLS speakers.

If I do the usual recommended action (i.e. reverse the leads at the speaker inputs connectors), wouldn't the main speakers be out of phase with the subwoofer?

(From a CJ preamp, the sub would be receiving an inverted signal, whereas the main speakers are being un-inverted.)

[admin]

Hi hoodjem,

First, welcome to CJO, great to have you with us.

Correcting for phase inversion is actually really easy. If you have an odd number of phase inverting components in your system, then you simple switch the positive/negative connection at the speaker. So the positive terminal from the amp you connect the the negative terminal of the speaker, and vice versa.

If you are employing a sub you have two options. If connecting via RCA outputs, then just change the phase to 180. If you using a speaker wire daisy chain, then do the positive/negative swap at either the amp speaker output or at the sub speaker input points. Ie so the phase shift is consistent between the sub and the speakers.

I'm a big fan of Margin Logan speakers and ran some Vantages for many years. I've said this before, but CJ gear sounds really great with planar speakers. Let us know what you decide, both the Premier 16 and 17 are great.

[hoodjem]

Admin,
Yes. I connect my ML Depth sub via RCA, so I can easily change the phase to 180.

Many thanks for this info,
hoodjem

[admin]

Happy to help. Enjoy the tunes.