Setting up subwoofer phase

[anonymous-user]

About to take delivery of my new BK sub and doing some research on setup.

What's the best way to set up the adjustable phase so it matches my main speakers? One option is here http://www.theabsolutesound.com/answers/5/ but it suggests reversing the polarity of my mains which I don't like the sound of incase it damages either the speakers or the amp.

Second option is to play a test tone at the crossover frequency (eg 80hz) and adjust the phase until it's loudest, measured using an SPL meter. I've found iPhone apps that will play the tone and measure how loud it is. Will this work?

[anonymous-user]

It's an active sub driven from the LFE output on the AV processor. There's only one way to connect it, then you use the phase control to adjust it so the crossover is smooth with the main, front speakers. From the manual:

"The P12-300 has a fully adjustable phase control to allow partial cancellation of the frequencies around the crossover point between the two systems. Listen to the quality of the bass with the phase in the 0 deg position and then slowly adjust towards the 180 deg position . Choose the position that subjectively offers the tightest cleanest bass."

Edited by anonymous-user on Thursday 5th May 18:50

[anonymous-user]

weeboot said:

Ah, in that case I am being silly, although we've at least confirmed that detail...

No worries!

[anonymous-user]

911newbie said:

Dug this out of search in case you chaps had any experience and comments.

I'm thinking about a sub for my 2.0 hifi in the living room.
Looking at the BK subs because they do seem the best.

Living room is 6.0m x 6.0m, normal ceiling height, full of sofas, and other family stuff.
Primarily for music, but possibly movies too.
Existing speakers are Monitor Audio Silver 100s. Amp is Arcam SA20, and it has a pre-out which I'd use for the sub.

Would the BK Gemini be sufficient ?
[url]http://www.bkelec.com/HiFi/Sub_Woofers/Gemini.htm[\url]
Or the P12
[url]http://www.bkelec.com/HiFi/Sub_Woofers/P12300SB-DF.htm[\url]

Don't need anything super massive loud, but equally the sub shoudn't be pushed.

Comments and experience very welcome.

Sorry, messed up the formatting for the URL. Arse !

Edited by 911newbie on Tuesday 5th January 13:49

Thanks for digging out my thread! I bought one of these monsters

http://www.bkelec.com/hifi/Sub_Woofers/P12300SB-DF...

Very good for music. To make it work correctly you’ll need a low frequency output on your amp (rather than pre out). This is because the crossover needs to be set so only low frequencies the sub can handle are actually sent to it.

Below about 80hz, bass becomes non directional so you feel it more than hear it. This means the sound will appear to come from your speakers rather than the sub.


Edit: I forgot my/these subs have a frequency control which you can set so you should be all good with your pre-out. Assuming your amp will of course power your speakers with the Pre-out in use.

Edited by anonymous-user on Tuesday 5th January 15:03

[anonymous-user]

911newbie said:

And was the P12 overpowering for your room ?
(and how big is the room it's in ?)

Does it ever feel pushed ? I guess not since it's got a quite powerful amplifier.

I'm concerned teh baby brother of yours, the Gemini, might be a little underpowered as a music sub, in a 6 x 6 living room (curtains, sofas etc)

Cheers !

Room is 30’ x 30’ and it never feels pushed. Watching films with explosions will make the windows shake! That’s on about 30% low gain (volume) which you can see from the picture above. Don’t forget you need to adjust the output to match the main speakers. Done right you don’t even notice it’s there, but like adjusting an equaliser. Bigger is better otherwise you may as well use your main speakers for low bass.

Edited by anonymous-user on Wednesday 6th January 10:36

[anonymous-user]

stevoknevo said:

It's more I can feel where it's
coming from, rather than hear it, due to old floorboards in this place Crackie - I'll try sticking a cushion under it for now and see if that helps. I was reading last week that the best way to set up with AVR's is to turn the crossover to max and let the AVR deal with it, so I did before running the room correction on the Anthem and it done a pretty good job to my ear TBH. I moved it right behind me earlier but haven't tested it yet.

This is what I did (see photo above). You shouldn’t be able to feel where the bass is coming from, I found a crossover frequency of 80hz worked well on my AV amp. Anything above that and you can tell where it is.

[anonymous-user]

paultownsend said:

To be fair I wanted the P12. BK said it still performed well with music but dug really deep for movies. But it’s massive, and I couldn’t get away with it!

Edited by paultownsend on Monday 11th January 21:59

To be fair, it depends what you class as massive. People occasionally ask “what the box in the corner is” but nobody trips over it. No point getting the small one unless you have satellite speakers and it does work very well with music or film.

[anonymous-user]

911newbie said:

I ordered the P12 300 from BK late in the evening on Monday this week.
Had a phone chat with a chap at BK about connecting it to a Class D amp - very clear advice there.

Email from BK to say usually 20-25 days delivery times right now.

It ships yesterday (that's actually one day after delivery), shows up just now. Simple to follow the instructions since the chat with BK.

All connected and sounding flipping amazing. Took 3 or 4 minutes.

I have to say this is simply amazing service and and flipping marvellous product from BK.
Can't wait till eveyrone is finished work/school later this evening in the house, so I can let it rip.

Glad you like it, they are a brilliant product and a great company to deal with. A decent sub makes everything sound better

[anonymous-user]

911newbie said:

We had a family disco last night.
Kids shouting at Mummy and Daddy to 'turn it down !' and 'not this rubbish please, Daddy'.
No taste at all, honestly.


Not sorry I bought it.

I have a Yamaha Aventage AV amp (sounds great) and a NAD Masters power amp powering ProAC floor standers, with the sub of course. About 1k watts of clean power. Friday night is music night in my house and we play various YouTube videos after a few beers. Kids used to come down from bed crying, holding their ears, complaining about the “boom boom boom”.

Now, a bit older they join in and play stuff when they are here but are often out and one’s at Uni. Both love music and play anything and everything all the time.

So persevere, they may cry now but it’s for their betterment.

P.s get your kids their own Spotify accounts under the family bundle. They’ll discover their own tastes.

Edited by anonymous-user on Friday 15th January 18:07