REL Acoustics How To: High & Low Level Subwoofer Tuning Step 1, Finding the Correct Phase

After completing the connectivity portion of your REL Subwoofer set-up, it's time to start tuning your REL powered subwoofer. The first set is to find the correct phase. In this video we show you how to find the correct phase and what you should be listening for.

[МаксимДолгов-ее]

Can I connect a subwoofer with a high-level input without speakers? Will it harm the subwoofer or amplifier? I want to buy a subwoofer on the secondary market, but there is no way to listen with speakers, there is only an amplifier.

[RennieAsh]

It would be nice to have a 180° fine tuning knob in conjunction, or just have a 360° dial. With this functionality, you can set the crossover frequency to be in phase by playing a sine wave at the frequency, having speakers or sub 180° out of phase and fine tuning until you hear the softest sound. Then switching 180° and you are good to go.
It’s easier to detect the softest sound out of phase than try to judge roughly the loudest when it comes to fine tuning.
Loudness method works for the simple switch

[RillenReiner]

Hi, received my T/7i today. While you make it look easy how to figure out the right phase in practice I find it not so easy. I used medium volume and as well sine sweeps 20 to 140 HZ and music, but I found it hard to hear the difference. Should I try more volume? Maybe measure with dB device at the listening position?

[PeterMacPL]

I have a question, have a REL T7/X connected to LFE input on REL from chinese amp Loxjie A30 which have "SW OUT".
But with this connection I can't control crossover on REL, do not work
Do I have to connect RCA cable from Loxjie to "Low Level Input" on REL instead "Low.1/LFE" ?

And second question, another setup with REL HT 1003 connected to AVR Onkyo 905 receiver.
I have connected it to LFE white color input in REL HT 1003, also no crossover control on sub.
Do I have to connect RCA cable to red RCA input "Low Level Input" in sub or use Y-Cable adapter to connect ?

Thank you.

[danboy]

I heard Rel don’t recommend using Denon as they only allow Crossovers down to 40hz, is this a problem if my front speakers range is 40hz - 33khz?

[Justwantahover]

So you are saying that the actual pumping action of the woofers and the sub can be opposite but still "in phase" cos of the acoustics?

[howardskeivys]

If only it were that simple. Simply, it’s not. I recently invested in a pair of T9I subs to augment the low frequency response of my Kef R11 speakers, not that they need much augmentation. I thought the phase control would make night and difference, surely if the Rels are working in phase with your main speakers as opposed to against them, the difference should jump out and hit you in the chest. It doesn’t! It’s very subtle!

My dealer advised me to leave the phase set as it came out of the box. Indeed, set this way, the leading edge of the bass note is better defined, like plucking a string with a plectrum, rather than your finger. It’s tighter and cleaner!

Rob, from Rel advised me to reverse the phase. Indeed, when I do this the bass is definitely, stronger and fuller, which Norman Hunter suggests in his ‘how to’ videos is the optimum setting, but this gives a very slight woolly, less defined edge to the bass.

The difference is so subtle, that I wonder, In a blind test, could I actually tell the difference.

All that having been said, those Rels transform my sound system from excellent to superb. I’m glad I went with the T9I and not a lesser sub as I don’t think a lesser sub would have complimented the Kefs with such authority.

I’ve now had the Rels in situs’ for 3 months and I really cannot decide which is my preferred or which is the correct phase setting. I’d be interested to hear if anyone else has a similar quandary? Vig

[wbmgr]

They make free apps for your phone that you can download which play a tone through your system which is specifically designed to check phase and it will tell you whether the system is in phase out of phase. All you have to do is connect the phone to your preamp with an aux cable or Bluetooth and play the test signal and then you can let the phone pick it back up through the microphone and on the app I have the screen will show either red or white and say on the screen either in phase or out of phase.

Makes the process very painless.

[jarmohyvarinen]

In my vintage system I have a Rel Q50 connected via speacon to my dual-mono Onkyo A9755 integrated amp which drives my old Kef reference 201 speakers. Adding sub to this system creates better soundstage and imagination. I've found a right phase but still sound at the bottom end, is too rounted. Roll off controll knob is a min position and volume control is about 5-8 steps from minimum. If I raise volume, or roll off control higher the music set's overall soud gets worst/more rounted. My Kef 201 ref is about 55hz -6db. Now the position of the Q50 is about 30cm from the front left corner and about 80cm from the left speaker. Is positioning of the sub problem here, or what I should do? Thanks👍

[Halkerik]

Какая площадь помещения рассчитана под этот REL HT/1003 !?

[rico]

I have a (vintage?) Q201E which has separate knobs for LO LEVEL and HI LEVEL, a four position MODE switch, and a ROLLOFF knob (100HZ - 25HZ). The MODE choices are:
1 LINE 0 Phase
2 LFE O Phase
3 LINE 180 Phase
4 LFE 180 Phase
To determine phase for music sources would I set both HI and LO knobs biased towards MIN then evaluate what music sounds best between modes 3 and 1? For movie source evaluate between modes 2 and 4? Thanks!

[futureshock]

I find there is a tradeoff between loud and full

[Duijnkiller]

My trade off is Loud boomy or less full.

[dragonflyfab]

What if the phase at cross over freq is 90* or 270*. That is why I now use full range speakers with no cross over.

[sudd]

hmm, in the example you use a subwoofer with passive radiator, you can't fix that phase issue with a knob.

[thomaspai]

I want to like this video but it's sitting at 420.

[Capitan_Cavernicola_]

My ears cannot make the difference. I hear no difference whatsoever. I asked my son for help and he cannot hear it. Wonder what I am doing wrong. Rel’s suggestion of a subwoofer tuning track or sound could help.