I plugged one of my old Peavey 15DL speakers into the 'center' speaker plug on the sub ... lowered the volume on the sats and cranked up the main volume a bit ... really clear sound and with no doubt a LOT of volume to spare ...
For most of the gigs I play, the Z-55 set up is more than enough ... I've not yet had to use the 'boost' feature ... but I now am confident that for a couple of outdoor summer gigs, the sub and 2 15 DLs will more than fill my needs ...

PS I don't have any literature on the 15 DL spkrs ... and of course they are pretty old (15 - 20 years ?!?) so I can't get any info off the I'net ... Can anyone provide me with any info on these? ... There is a 15" and what looks like a couple of 'tweeters' ...
t.

[This message has been edited by tony mads usa (edited 03-22-2006).]

I'm curious if they are powered or non-powered speakers.

Scott... just plain ol' non-powered speaker cabs ...
t.

Tony:

Gives me a thought for one of my Klipsch speakers

just be careful you are not driving the amp in your system down to a 2ohm load.will be okay at low levels but when "cranked" the amp works much harder generating a lot more heat, and if the heat sinks cannot dissipate this the amp shuts down...if its a newer amp it will be only temp as they usually have a thermal protection device designed to shut down before real damage occurs..but still embarrasinf right in the middle of a song!!!

Tony,

Your extra sound level mostly comes from the higher sensitivity rating of the larger 15 DLs. As you probably know, the sensitivity is basically a rating of how much sound pressure is generated at 1m distance when given 1W of input power. Smaller drivers like the 3" satellites typically put out less than 90dB (for 1W@1m) whereas larger drivers like your 15's can generate around 100dB for 1W input. This is more than 10dB sound output for the same signal power input, and subjectively would sound at least twice as loud. It's basically a function of the larger surface area of the 15" being able to shift more air than the smaller 3".

I have not measured the impedance rating of the z5500 satellites but would expect them to be in the 4 to 8 ohm range. Miden is right in warning about the possible impedance mismatch, but your 15 DLs should be okay and hopefully should be rated at somewhere between 4 and 8 ohms. You can check this in a crude fashion with a cheap multimeter. As long as you stay above the minimum rating per amp channel, everything would be OK.

If you attach speakers that are lower impedance than the satellites, but are still above the minimum impedance rating of the amp, this would also be OK and would contribute to the increased sound output level, becasue the amp would be able to deliver more power into the lesser load impedance. As Miden said, just be careful to check things first.

Please consider that this description is very much generalized as there is a bunch of other parameters that also affect the sound output level. But hopefully it is of some use.

Mark

[This message has been edited by batty (edited 03-23-2006).]

miden and batty ... thanks for the feedback ... this is what the specs for the z-55s says:Input impedance: 8,000 ohms ??? ...I will try to find out how many ohms the 15DLs are ...
I am thinking that for large gigs I would use the DLs feeding off the sub, and not use the sats at all ...
t.

Tony,

There's a big difference between the input impedience and the output impedience. The output impedience is the one you must be concerned with when it comes to the speakers--and this is 8 ohms. Therefore, I suspect you'll be just fine using those old speakers. Most were 8 ohm speakers, even those with a couple tweeters installed in the cabinets.

Good Luck,

Gary



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Travlin' Easy

the only problem is that when speakers are connected in parallel, (as i assume these are..(its the standard way of wiring + to + - to -) the impedance drops by half..eg 2 x 8 ohm speakers in parallel = 4ohm impedance, add another 8 ohm speaker you get to appprox 2.9 ohms, add another 8ohm speaker and you get 2 ohms....so looking at his setup.. (and the capacity of the speakers is irrelevant even the small satellites they may be small but if they are 8 ohms they must be added int o the impedance equation).. he is already using 3 8 ohm speakers, the impedance on the amplifier driving this is already getting a bit low..of course if the original speakers are say, 16ohms, or are wired in series, then no problem..all that happens is the nominal power of the amplifier reduces..another example would be: 2 8ohm speakers in series = a 16 ohm load...lets say the the amp output power into 8 ohms is 200 watts, at 16ohms it reduces to about 125 watts, so ergo if you keep adding speakers in series you cant blow anything up it just gets quieter..in the real world though pretty much every speaker is wired in such a way that when 2 are added together it is in parallel..hence my advising to check the impedances of the speaker..mind you if the amp is say a 200 watt amp and you are only running it at 75 watts, you could prob even go to 1 ohm (IN THEORY!!!!!) for short spells, but the other issue is that at these low levels of impedance the amp can go DC almost instantly, and DC WILL burn out your voice coils in a matter of seconds...even just dropping a mic is enough of a spike for the power rails to go DC.....i am just advising caution NOT doom and gloom..

Thnx for the input, guys ... this is like a course in audio electronics ... ... this is also why when we had the band all those years in NY, we left the audio responsibility to the guitar player who was into this stuff ... ...
t.