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Author Topic: Where to align the main speakers to the subwoofers?  (Read 3986 times)

Merlijn van Veen

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Where to align the main speakers to the subwoofers?
« on: June 01, 2016, 11:32:18 am »

Uploaded a new video lifting the veil regarding the prevailing question "where to align the main speakers to the subwoofers".

Click here to watch it.

Sincerely and enjoy,

Merlijn van Veen
« Last Edit: June 02, 2016, 04:51:15 am by Merlijn van Veen »
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Tim McCulloch

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Re: Where to align the main speakers to the subwoofers?
« Reply #1 on: June 01, 2016, 12:16:13 pm »

Uploaded a new video lifting the veil regarding the prevailing question "where to align the main speakers to the subwoofers".

Click here to watch it.

Sincerely and enjoy,

Merlijn van Veen

Very nice, Merlijn!
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Rob Spence

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Re: Where to align the main speakers to the subwoofers?
« Reply #2 on: June 01, 2016, 12:34:08 pm »

Very nice. Thank you.


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Dave Pluke

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Re: Where to align the main speakers to the subwoofers?
« Reply #3 on: June 01, 2016, 05:47:59 pm »

My head hurts....but, thanks Merlijn  ;D !
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Nitin Sidhu

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Re: Where to align the main speakers to the subwoofers?
« Reply #4 on: June 02, 2016, 06:15:27 am »

Thank you Merlijn!

Excellent watching!
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John L Nobile

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Re: Where to align the main speakers to the subwoofers?
« Reply #5 on: June 02, 2016, 08:13:02 am »

Very informative. Thanks for posting this.
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Rob Spence

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Re: Where to align the main speakers to the subwoofers?
« Reply #6 on: June 03, 2016, 12:19:12 am »

Now if I could only figure out how to align them....


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Frank Koenig

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Re: Where to align the main speakers to the subwoofers?
« Reply #7 on: June 03, 2016, 12:01:11 pm »

Merlijn, a clear presentation, as always. Thanks. My two take-homes are the notion to align at the upper end of the frequency overlap (~1/3 octave over) rather than at the crossover frequency, as the spacial region of summation is smallest for the shortest wavelengths, and the benefit of using a lower crossover frequency.

Another tradeoff I believe is employed sometimes is to further separate the low- and high-pass cutoff frequencies and to accept a dip in the overall response in exchange for less audible interference.  I guess this is cheating and should not be necessary in a well deployed system, but in a pinch it can help to clean up the "mud". I would be interested in your observations on this practice.

Best,

--Frank
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Merlijn van Veen

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Re: Where to align the main speakers to the subwoofers?
« Reply #8 on: June 04, 2016, 02:32:47 am »

but in a pinch it can help to clean up the "mud".

DISCLAIMER: Don't take this personally.

IMO that's because most have created the mud to begin with, by raising the subwoofer levels to achieve low frequency emphasis.

In a unity crossover, mains and subs are equally loud at the actual intended crossover frequency for a given point in space. However, if you raise the subwoofer levels you shift the frequency up which was previously equally loud and the subs now have custody over an extra half octave or so. There's your mud.

So to counter it you lower the corner frequency of the LPF proportionally, thinking you introduce a gap. But effectively you're restoring the original crossover frequency albeit with mismatched phase slopes because the LPF and HPF now have different corner frequencies.

It's a can of worms that from my experience only works with 60 Hz crossover setups because by the time you've haystacked the subs to +12 dB you're effectively back at 80 Hz to 100 Hz.

I like LF as much as anyone but in the pursuit for emphasis ALL we're trying to achieve is SEND MORE VOLTS to the subwoofers and that can me done in more than one way besides cranking up the sub amps.

You could also use a low-shelf filter for the same effect which is MORE VOLTS to the subs. In this approach however you maintain the level custody between mains and subs and respect the intended crossover frequency.

Yes, this will cost you headroom because now the low-shelf will trigger the limiters earlier on but maybe then more rig for the gig is called for...

End of rant ;-)



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Frank Koenig

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Re: Where to align the main speakers to the subwoofers?
« Reply #9 on: June 04, 2016, 11:37:04 am »

You could also use a low-shelf filter for the same effect which is MORE VOLTS to the subs. In this approach however you maintain the level custody between mains and subs and respect the intended crossover frequency.
End of rant ;-)

Thanks for the rant -- it benefits us all. I completely agree that LF boost is a subjective EQ decision that should be applied upstream with respect to a particular source, and that a properly aligned crossover should be left alone.

I, like everyone else, use an LF boost shelf for playback of recorded music, with the exception of cinema which always seems to have plenty of bass (my cinema experience is limited to my living room, and it's not a "calibrated" system). Live, if I want more bass (frequency range) I turn up the bass (guitar, drum, etc.)  ;)

Best,

--Frank
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Mark Wilkinson

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Re: Where to align the main speakers to the subwoofers?
« Reply #10 on: June 05, 2016, 02:35:18 pm »

Many Thanks Merlijn, Very nice.

Trying to get an intuitive feel for aligning to 1/3 oct above crossover.....and for aligning to rear...
Are these mainly due to trying to overcome the geometry of sub-to-main separation?

I get the point about longer wavelengths allowing more wiggle room to offset relative distance changes.
I'm also thinking that the increasing sub group delay (as freq drops) is working to advantage to overcome moving closer to speakers too ...???

If subs and mains are adjacent,  would you align to x-over freq, or 1/3 up? 

Oh, I assume the calculator is seeded with LR24 .....?
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Merlijn van Veen

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Re: Where to align the main speakers to the subwoofers?
« Reply #11 on: June 05, 2016, 03:32:02 pm »

Overcoming the geometry of the sub-to-main separation as you call it, is the very function of this calculator.

The 1/3 8ve up, only matters for determining the actual alignment position (not the phase alignment itself) when you decide to abandon the approach of aligning in the back of the venue or if you're sources aren't co-located.

How far you can move forward is determined by how much phase offset in the back you're willing to except which IMO is 120deg at most before the onset of cancellation. Since typical crossover ranges have a span of 1 octave it makes sense to look at the "higher" frequencies because there's less wiggle room for determining the positions.

More and more systems are already aligned if the speaker grills are physically aligned and group delay is already accounted for.

The crossover order and how to account for it is up to you. 8th order range is about a fifth so you might as well look at the actual crossover frequency. 4th spans about 1 octave so look 1/3rd up and 2nd spans almost 2 octaves so look 2/3rd to 1 octave up.


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Mark Wilkinson

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Re: Where to align the main speakers to the subwoofers?
« Reply #12 on: June 05, 2016, 04:08:52 pm »



The 1/3 8ve up, only matters for determining the actual alignment position (not the phase alignment itself) when you decide to abandon the approach of aligning in the back of the venue or if you're sources aren't co-located.

How far you can move forward is determined by how much phase offset in the back you're willing to except which IMO is 120deg at most before the onset of cancellation. Since typical crossover ranges have a span of 1 octave it makes sense to look at the "higher" frequencies because there's less wiggle room for determining the positions.


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Thank You, ......picturing it.

I've been working with flat phase alignments of adjacent subs/mains....trying to conquer geometric separation first.
Step at a time  :)
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Re: Where to align the main speakers to the subwoofers?
« Reply #12 on: June 05, 2016, 04:08:52 pm »


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