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Re: LAB12 [message #69763 is a reply to message #69762]

Sun, 09 October 2011 08:55

Wayne Parham
Messages: 18678
Registered: January 2001

Illuminati (33rd Degree)

Yes, I believe it would. Good find - I may bring one in to try it too.

Remember though - You don't want to high-pass the mains like you would in a prosound environment. Most times, in the prosound world, the speakers are used in a very large room where modes are not a problem. They're below the passband. But in our homes, rooms are much smaller and standing waves become a problem. That's what we want multiple sound sources in the 20-200Hz range.

Long story short - Use the low-pass section to drive the subwoofer amp, but send a full range signal to the mains.

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Re: LAB12 [message #69765 is a reply to message #69751]

Sun, 09 October 2011 10:16

themilford
Messages: 66
Registered: May 2009

Viscount

...Will do... Thanks Wayne.

However we will be using the roll-off feature on the Genelecs to "protect" the sorry woofers... There's a bunch of settings and I will choose the one that only rolls off just enough to omit the woofer buzz...

If I decide to go for only one sub for now will I be ok?

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Re: LAB12 [message #69766 is a reply to message #69765]

Sun, 09 October 2011 11:24

Wayne Parham
Messages: 18678
Registered: January 2001

Illuminati (33rd Degree)

Honestly, no. If you have one sub and the mains are high-passed to rolloff bass from them, you have only one bass sound source, which is a worst-case scenario. I mean, nothing will break but bass and lower midrange response will be lumpy.

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Re: LAB12 [message #69767 is a reply to message #69766]

Sun, 09 October 2011 12:14

themilford
Messages: 66
Registered: May 2009

Viscount

If it matters, the bass rolloff on the Genelecs is:

"Bass roll-off control operating in 2 dB steps from 0 to -8 dB @ 50hz"

I think the attenuation is all below 60hz maybe even lower with the "roll-off". I'll need to play around with it. there's also a "bass Tilt" control but I wouldn't be using that I don't think.

Here's the model:
http://www.genelec.com/1030a/specs/

Manual has the info on the tone switches.

Not sure we can fit two 20" cubes in the control room behind the desk... might be a tight squeeze.

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Re: LAB12 [message #69768 is a reply to message #69767]

Sun, 09 October 2011 12:22

themilford
Messages: 66
Registered: May 2009

Viscount

Just read the manual:

The -4 roll off and the -4 bass tilt are suggested to be engaged for near-field/desk set-up.

These would be engaged anyway... in a normal studio setup.

Not sure we had them set that way.

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Re: LAB12 [message #69770 is a reply to message #69751]

Mon, 10 October 2011 09:50

Marc321
Messages: 8
Registered: April 2011

Esquire

Interesting. Even though I really like my Genelec 8050's (8" 2way). I plan on building some 4pi at some point. I'm trying to sell my Genelec's (2000.00 for the pair). Retail is approx. 5K. Maybe your boss might be interested? Then I can start my pi speakers!

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Re: LAB12 [message #69772 is a reply to message #69770]

Mon, 10 October 2011 10:34

themilford
Messages: 66
Registered: May 2009

Viscount

Hehe... Thanks but we're broke. The studio is barely scraping by.

That's the beautiful thing about Pi Speakers... if you have the means to build kits you can outfit your studio with world-class monitoring at a fraction of the industry price.

So, I built my TwoPIs a while ago and have been enjoying them at home... they are great. But they are a stand-in until I replace the woofers in my Audio Note Js... I have them I just need to install them.

I also have the components for the ThreePI loudspeakers on hand and just need to fabricate the cabinets.

I'm assuming with the smaller control room the TwoPIs will be a better match than the larger ThreePIs which will be more useful as hi-fi PA speakers in the "live" room for keyboard, playback and reamping

I'm sure the TwoPIs will play louder and more dynamic than the Genelec 1030A monitors. We have Hafler P3000 for now but eventually I have a Dynaco ST-70 to run the PIs and we'll use the Hafler on the sub(s) once that/they are built.

BTW: how low would I cross-over the 3PI-Sub with the TwoPIs. Probably a single sub for now until I can buy/build another.

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Re: LAB12 [message #69774 is a reply to message #69772]

Mon, 10 October 2011 12:52

Wayne Parham
Messages: 18678
Registered: January 2001

Illuminati (33rd Degree)

The crossover to the sub depends almost entirely on the distance from the main speaker(s). The further away, the lower crossover needs to be made. I think a good rule of thumb for indoors use is to crossover around 1/3λ. Outdoors you want to bring this down to under 1/4λ.

To know what frequency that is, use this simple formula, where x is distance between main speaker and sub: f = 376/x

This 1/3λ rule only applies to closely spaced woofers, up to about six feet. Past that, there's really no need to go any lower in low-pass frequency. Don't low-pass below 50Hz or 60Hz, even for distant subs.

For indoors use, what's more important than distance between mains and subs is distance to boundaries. If the mains are soffit mounted, baffle flush with the wall, then this distance is zero and that solves a lot of problems. But if it's not, then it's best if the distance from sub and listener is different than the distance between main speaker and listener. Ideally, this difference will be at least half the distance between the main speaker and the wall behind it. The goal is to stagger the frequencies where there is self-interference from boundaries.

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