Speaker/Phase alignment... does it matter?

[DJ Jules]

The gig I did last night was on a installed rig, but after seeing how the rig was wired (not exactly expertly) it got me wondering...

Basically the rig was a pair of JBL 125's (HF horn + 2 x 15" LF drivers) and a pair of peavey 18" bins. The JBL's were being driven full range with no filtering and the amp for the bins was being driven through an active low pass filter (set to feed them with anything below 160hz). The tops were just sat on the bins and the face of the JBL's was set back from the bins by about 15cm.

Simple question really - does it matter than the JBL's were being driven full range and/or that the faces were out of alignment - is it possible that doing this could be distorting/reducing the LF output of the rig (bearing in mind it's also quite possible that the signal driving the tops and bins could be inverted?) The crossover I just sold had the option to add a configurable delay either the LF or HF signal path, so I've always assumed that it does?

I tried to do a bit of the math on my way home last night, and in theory the time taken for the sound to travel the 15cm gap would be something like 454 microseconds - which I'd expect to be imperceivable?

Does it matter? What would you recommend is done to this set up?? I'm probably going to be back in this venue, using the same rig in a few weeks - should this be "fixed?"

Julian

[Excalibur]

You're heading rapidly out of my area of knowledege, but I'd have expected out of phase drivers to be the likeliest cause of perceived reduction in bass. With a rig like you've described, it should be loosening your fillings!!

[DJ Jules]

You're heading rapidly out of my area of knowledege, but I'd have expected out of phase drivers to be the likeliest cause of perceived reduction in bass. With a rig like you've described, it should be loosening your fillings!!

It rumbles nicely from behind, but it's quite "muddy" from in front. The whole set up is quite dubious, the tops are being driven by an old 4U MOSFET 2kw amp and the subs by a Berry Europower 1kw amp!

Julian

[TONYTIGER]

It rumbles nicely from behind, but it's quite "muddy" from in front. The whole set up is quite dubious, the tops are being driven by an old 4U MOSFET 2kw amp and the subs by a Berry Europower 1kw amp!

Julian

Are all the speakers same design ,as you get problems mixing say folded horns with direct radiating designs.

[DJ Jules]

Are all the speakers same design ,as you get problems mixing say folded horns with direct radiating designs.

It did occur to me that folded horns would make the problems far worse, but as far as I know the Peavy bins are direct radiating, the JBL's definitely are.

In general, would it be best just to filter the bass off the tops to avoid any possible interference?

Julian

[Excalibur]

It did occur to me that folded horns would make the problems far worse, but as far as I know the Peavy bins are direct radiating, the JBL's definitely are.

In general, would it be best just to filter the bass off the tops to avoid any possible interference?
Julian

You said the subs are fed from a crossover. Could you not feed the tops from the hi out on this, and see what happens? I'd expect an improvement.

[DJ Jules]

You said the subs are fed from a crossover. Could you not feed the tops from the hi out on this, and see what happens? I'd expect an improvement.

I expect they can be - I'm going to have to find a manual for the crossover first though as it's a 2 way Berry with Hi, Mid and Lo output's with adjustable crossover frequencies for each.

I expect the guy who did the original install thought he'd get more kick wiring it as he has (with quite a lot of insulation tape :eek:).

Julian

[Excalibur]

I expect they can be - I'm going to have to find a manual for the crossover first though as it's a 2 way Berry with Hi, Mid and Lo output's with adjustable crossover frequencies for each.

I expect the guy who did the original install thought he'd get more kick wiring it as he has (with quite a lot of insulation tape :eek:).

Julian

2310? If so, you may have to do a bit of investigating. The mid, Hi, Low option is only available in mono. Otherwise, I think you only get Hi and Low in the more usual stereo option. the 3410 is genuinely 3 way stereo. Behringer manuals are usually easily found on the Behringer site.

By the sound of it, proceed with caution.

[DJ Jules]

2310? If so, you may have to do a bit of investigating. The mid, Hi, Low option is only available in mono. Otherwise, I think you only get Hi and Low in the more usual stereo option. the 3410 is genuinely 3 way stereo. Behringer manuals are usually easily found on the Behringer site.

By the sound of it, proceed with caution.

I've just found the manual - it's a Berry Super X-Pro 3400. If I get this a regular gig, I'm rewiring the place first! It's the 4kw of amps plugged into the 4 way strip, plugged into the 10way strip, plugged into a 13A socket next to the additional 1.5kw of lighting which scares me.

Actually, I think I'll push for an electrician to rewire the place!

Julian

[Excalibur]

I've just found the manual - it's a Berry Super X-Pro 3400. If I get this a regular gig, I'm rewiring the place first! It's the 4kw of amps plugged into the 4 way strip, plugged into the 10way strip, plugged into a 13A socket next to the additional 1.5kw of lighting which scares me.

Actually, I think I'll push for an electrician to rewire the place!

Julian

True 3 way, I believe. Don't tell me our intrepid installer has done something "creative" with the wiring to get a three way sound, out of a two way rig? :confused: :eek: :D :D :D :D :D Good luck. ;)

[DJ Jules]

True 3 way, I believe. Don't tell me our intrepid installer has done something "creative" with the wiring to get a three way sound, out of a two way rig? :confused: :eek: :D :D :D :D :D Good luck. ;)

Nope, reading the manual the Berry can be configured to run in either 2 or 3 way modes. I didn't realise but the Crossover has a Run-Time correction control as well... I'm going to get in early next time and have a play with some settings :D

Julian

[Excalibur]

Nope, reading the manual the Berry can be configured to run in either 2 or 3 way modes. I didn't realise but the Crossover has a Run-Time correction control as well... I'm going to get in early next time and have a play with some settings :D

Julian

You are correct, Sir. My error. :o I don't know, but I wonder if the crossover is adding a delay, and thus a phasing problem? :confused:

[DJ Jules]

Just a quick update on this one - I played on this rig again last night and went prepared with the manual for the Crossover to see if I could tune up the system a little.

So, go to the venue, powered up the booth, switched on the crossover and the Amps and one went BANG with a shower of Sparks.

One quick rewire later and we're running with just a Behringer EP2000 amp driving a pair of JBL JRX125's and the subs are taking a break for the night. Problem solved :D

If anyone has a spare amp they want to sell (EP2000 kind of power - 600w/channel into 8ohms or better - but not a 20yr old pile of :censored:) the venue is looking to buy one :)

Julian

Julian