Unorthodox 2x18 slot loaded PA sub

[petterhaus]

+/-3dB, close enough for rock & roll ;^).

The deep notch at 180Hz is interesting, looks like the plenum and port output may be 180 degree out of phase at that frequency, usually that sort of dip would show up in the simulation. That said, Hornresp is assuming one port, but there are four, so the port's "pipe resonance" will not be the same.

Some interesting discussion in this thread:
https://techtalk.parts-express.com/...5-port-resonance-what-should-i-be-looking-for

If the ports are capped off (covered/stuffed), does that dip still show up in the response?

HI Art
Cabinets are finished!
unfortunately with 4 ports there wasn't space enough and the pipes went against the cone baskets.
If the weather allows me tomorrow I will test the whole pa at high spl in free field and check if the dip disappear!

I need to assemble dsp blocks on my audia solo 8x8.
I would to insert rms compressor and peak limiters (not a real limiter but the same comp with 100:1 ratio and 0.1ms attack possibly) each channel.
The rig is:
sinbosen k450 4x450 at 8ohm for the 2 channel of dcx464-8
proel psw2600 2x1300rms at 4ohm for 2xrcfmb12n351-8 wired in parallel per channel
sinbosen fp14000 2x2400rms at 8ohm for 1 18115-8 per channel.

How I can adjust limiters in the dsp to have good performance and safety ?
this powersoft manual is xhaustive?
Thank you very much

 

[weltersys]

How I can adjust limiters in the dsp to have good performance and safety ?
this powersoft manual is xhaustive?

I can't think of anything not already covered in the Powersoft manual to help you further with adjustment of peak and long term (thermal) limiters.

 

[petterhaus]

hi guys
Finally tested the complete system in a free field
what I found is :
.the synergies tops are really really impressive: I don't remember a small PA with this sound quality in the details, dynamic, pattern control, low self noise, and power capabilites. at highish spl at 20meters I lowered the highs few dbs maybe for Fletcher-Munson curves even if in Smaart there was flat respone.

. I'm happy also for the sub, big punch and spl but I had 4 considerations:
1-with secondary flare installed I could see by eyes the bottom and top panel vibrating +/-5mm and so the extension was jumping on the floor causing unwanted noise. I would add a removable vertical bracing in the middle.

2-i had some noise without extension also: the boxes are glued and screwed (around 200 5x40mm wood screws) It is possible the screws cause rattling noise?I think yes so I wil try removing.

3-I also covered the internal sides of the port with open texture tnt tissue only for procecting the cones from the dust. Is not recommended to cover the ports like I did?

4-the sub drives(8ohm each) are wired 1 for fp14000 channel,doubled mono signal from the dsp. with -4db leds flickering witch 7mm (by eyes) excursion
can I achieve high spl running drivers in parallel 4 ohm and fp in bridge mode?
(with sub at same volume of the tops, the tops amps weren't even flickering the signal leds almost).

my doubt is also that covering br ports lowered the max sub spl.
here some system pictures in my car box.

Thank you
Ale

 

[David Morison]

Those sprung handles are much more likely to rattle than the woodscrews.

 

[petterhaus]

Those sprung handles are much more likely to rattle than the woodscrews.

Hi I forgot to mention that I tested also without handles!
Ale

 

[Booger weldz]

The extension To the original box/waveguide add on

 

[weltersys]

2-i had some noise without extension also: the boxes are glued and screwed (around 200 5x40mm wood screws) It is possible the screws cause rattling noise?

The only way screws would rattle is if they split plys apart in the plywood. Run a slow sine wave sweep to find the frequency that causes the rattles, then use a cardioid microphone (cut the low frequency) through headphones to listen closely to what is rattling. Might be the port supports.

3-I also covered the internal sides of the port with open texture tnt tissue only for procecting the cones from the dust. Is not recommended to cover the ports like I did?

If the cloth is breathable (like speaker cloth) it should have no effect on output.

4-the sub drives(8ohm each) are wired 1 for fp14000 channel,doubled mono signal from the dsp. with -4db leds flickering witch 7mm (by eyes) excursion
can I achieve high spl running drivers in parallel 4 ohm and fp in bridge mode?

You were using around 1100 watts if you had 4dB left.
"By eye" usually means peak to peak, which would only be 3.5mm one way. Not much excursion.
7mm one way would be only around half Xmax, which means another 6dB before running out excursion, a couple dB more than the 4dB you had left.
Going from 2350 watts per driver to 7000 would definitely get the cones jumping, you would need to limit the RMS power way down from that.

Art

 

[kipman725]

.the synergies tops are really really impressive: I don't remember a small PA with this sound quality in the details, dynamic, pattern control, low self noise, and power capabilites. at highish spl at 20meters I lowered the highs few dbs maybe for Fletcher-Munson curves even if in Smaart there was flat respone.

its normal to apply EQ from flat, it depends a bit on taste, music genre and the acoustics of the environment you are in but generally there is:
1) bass boost below 100Hz, this can be >+10dB
2) overall spectral tilt so that the highs are reduced
3) perhaps a cut around 2.6kHz due to the ear canal resonance

There is a lot written about target curves for small rooms in the home but in larger spaces and at higher SPL and with varying intrinsic EQ to recorded music there isn't a unaversaly applicable target curve. I tend to basically contour the system and correct room modes in the processor and then apply additional bass boost and any cuts to reduce harshness on the desk.