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Electro-Voice | QRX-218S

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Re: Electro-Voice | QRX-218S

Postby manleyelop » Sun Jan 13, 2019 8:23 pm

Wonks wrote:What length cables do you normally run? Minimising cable length also helps.
Hmm im not quite sure sometimes i link one to another if i need more length im not sure if that's a no no or sometimes it's too long so it's curled up i just prep as good as i can with what i have available
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Re: Electro-Voice | QRX-218S

Postby Sam Spoons » Mon Jan 14, 2019 11:59 am

Linking cables is not unusual but long cables will have more volt drop so you probably need to compensate by using thicker wire.
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Re: Electro-Voice | QRX-218S

Postby Wonks » Mon Jan 14, 2019 12:02 pm

Loosely coiled is fine. Just avoid very tight coils, where a lot of the cable isn't exposed to the surrounding air as it encourages heat build-up and also adds some extra inductance to the cable.
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Re: Electro-Voice | QRX-218S

Postby manleyelop » Mon Jan 14, 2019 1:56 pm

Wonks wrote:Loosely coiled is fine. Just avoid very tight coils, where a lot of the cable isn't exposed to the surrounding air as it encourages heat build-up and also adds some extra inductance to the cable.
Right Ok understood cheers guys i reckon i need a new power amp & some thicker cables
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Re: Electro-Voice | QRX-218S

Postby Sam Spoons » Mon Jan 14, 2019 3:36 pm

Try the cables first, you never know and they'll be cheaper than a new amp.....
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Re: Electro-Voice | QRX-218S

Postby manleyelop » Mon Jan 14, 2019 4:18 pm

Sam Spoons wrote:Try the cables first, you never know and they'll be cheaper than a new amp.....
yes good idea :thumbup:
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Re: Electro-Voice | QRX-218S

Postby manleyelop » Mon Jan 14, 2019 4:23 pm

By the way guys so how do i work out how loud my p.a is ive heard the term it's a 2k rig (2000watts)

do i just add up what both my poweramps can kick out?
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Re: Electro-Voice | QRX-218S

Postby manleyelop » Mon Jan 14, 2019 4:29 pm

just checked my cables box & it seems im using 2.5 cabling with the odd 1.5 so you recommend using 4mm only for the subs?

also what's the x10 led on the dbx crossover gonna have a read but im not sure what it's for seems it changes the crossover frequency
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Re: Electro-Voice | QRX-218S

Postby Sam Spoons » Mon Jan 14, 2019 4:46 pm

manleyelop wrote:By the way guys so how do i work out how loud my p.a is ive heard the term it's a 2k rig (2000watts)

do i just add up what both my poweramps can kick out?

It's a little more complex than that, especially with separate amps and speakers. Power does give an indication but speaker sensitivity is equally as important (more power or better sensitivity will both get you louder but so may better gain structure and positioning to reduce feedback and many other factors). Realistically I wouldn't bother, if it's loud enough to do your gigs and sound good (not distorting or running out of steam) then it's fine.

4mm2 for subs and as short as is practical. keep the 1.5mm cables for small pub gigs.
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Re: Electro-Voice | QRX-218S

Postby Wonks » Mon Jan 14, 2019 4:49 pm

If you are running any distance, then I'd use 4mm² for the subs and the 2.5mm² for the tops. Keep any 1.5mm² for emergency backup only.

To know how loud your speakers are, there's nothing like actually measuring them with a decibel/sound level meter. You can get decent ones from around £40 upwards. The demise of Maplin means that there's not one I know of that's been recommended, but beware of very cheap ones on eBay and Amazon. They normally peak at about 130dB, but that is very loud, and you really would need to be wearing hearing protection.

This one from RS looks reasonable. https://uk.rs-online.com/web/p/sound-le ... s/1558902/ for general measurements. Without a calibration certificate, the reading will be within about 3dB of the true value. So it's great for general indication and also comparative readings e.g. try tweaking your mixer and crossover settings and see if there's a measurable improvement.

A -weighting will tell you what your ears will hear the sound like at reasonable listening levels, but C-weighting is flatter with less bass roll off, and better for loud sound measurements, so I'd use that for testing the rig.

Sound output is a measure of the speaker efficiency and the amplifier power going to it. So using amp wattage alone will not tell you how loud the system can go.
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Re: Electro-Voice | QRX-218S

Postby manleyelop » Mon Jan 14, 2019 5:19 pm

Wonks wrote:To know how loud your speakers are, there's nothing like actually measuring them with a decibel/sound level meter. Y
funny i actually own a meter from maplins but didn't think of using it :headbang: Precision gold NO5CC A /C but what's the fast or slow for ?

it's just sometimes i get asked we require a 2k rig or so on do you have one not often though to worry about
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Re: Electro-Voice | QRX-218S

Postby manleyelop » Mon Jan 14, 2019 5:20 pm

Wonks wrote:If you are running any distance, then I'd use 4mm² for the subs and the 2.5mm² for the tops. Keep any 1.5mm² for emergency backup only.
got it cheers both :thumbup:
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