series/parallel question

[BGJAZZ]

Usually I use a powered mixer for the FOH and run to another PA for the monitors. For some gigs, I'd like to bring as little equipment as possible so I'd like to use my powered mixer (ch A and B) for both FOH and mon.

If I have 4 FOH speakers (8ohms each) and the mixer is 500watts at 4ohms, I calculated that if I run 3 speakers in series and the last one in parallel, it will give me 6ohms in the end (if the math is right). These would run from ch A. Usually I always run the speakers in parallel (one cab to the next)

Sorry, I'll get to the point: Do I need special cables to be able to run 2 cabs in series? My cabs on have 1/4" jacks. Or better yet, is there another ways to feed 4- 8ohm speakers into 1 channel of the amp to achieve 4 or more ohms?

Hope this makes sense???
Thanks

[tlbonehead]

Originally posted by BGJAZZ
Usually I use a powered mixer for the FOH and run to another PA for the monitors. For some gigs, I'd like to bring as little equipment as possible so I'd like to use my powered mixer (ch A and B) for both FOH and mon.

If I have 4 FOH speakers (8ohms each) and the mixer is 500watts at 4ohms, I calculated that if I run 3 speakers in series and the last one in parallel, it will give me 6ohms in the end (if the math is right). These would run from ch A. Usually I always run the speakers in parallel (one cab to the next)

Sorry, I'll get to the point: Do I need special cables to be able to run 2 cabs in series? My cabs on have 1/4" jacks. Or better yet, is there another ways to feed 4- 8ohm speakers into 1 channel of the amp to achieve 4 or more ohms?

Hope this makes sense???
Thanks You really don't want to run three speakers in series and one in parallel. You won't get equal power to each. Also, if you chain your monitors and mains all together in any fashion you won't have any way to conrol them independently of each other. You REALLY don't want that. But to answer your question,yes,it is pretty easy to throw a little series "Y" adaptor together. Just wire it up in series the same way you would do series wiring inside a cab. A couple of better options would be to get a small single space power amp to run your monitors. Or get a powered speaker module from Parts Express or MCM for about $120 and throw that in one of the monitor cabs. You could run both monitors off of it. Lastly,no,you can get 4 ohms out of 4) 8 ohm drivers.

[ctardi]

You have two channels of powered mixer, do you not, a and b? Run the mains in parallel off A, and the mons off b, also in parallel. That gives you 2, 4 ohm loads, one for each channel. Then you will be able to make two seperate mixes.

That is unless your channel A and B are just parallel outputs of the same amp. What powered mixer do you have?

Also, you would have to put 2 in parallel, otherwise, it is just series. ;)

[bigmike216]

Originally posted by ctardi


Also, you would have to put 2 in parallel, otherwise, it is just series.

Uh, what?






You can series parallel them to get 8 ohms. Wire two pairs in series, and then parallel the series pairs. Wiring them in series won't give you any additional sensitivity, just more powerhandling. WIth this powered mixer, you won't gain anything in output by running the pairs in series, and then parallel, as you would just running one pair, parallel. You could get some better coverage though, if your cabinets array well... What cabinets are they? If they're not all the same, or if they have wiide dispertion HF horns, you will just make yourself a comb filtering nightmare.


As for doing series parallel with the mains and mons, go for it. You're trying to bring as little gear as possible for the tiny gigs, and that would do it. You won't have a proper monitor mix.. That might not be a problem though.

Here is a little diagram I made for you for the series wiring cable. it's pretty easy to make one with a plug and two jacks of whatever connector type you happen to use.

[ctardi]

If there is one thing in parallel, it is in series, unless it is parallel/series, which is what the op intended, but I missed the first time.

[bigmike216]

Originally posted by ctardi
If there is one thing in parallel, it is in series, unless it is parallel/series, which is what the op intended, but I missed the first time.

uhh?

If there is one speaker, it's nethier in series nor parallel..

There is no way something can be in parallel, while being in series at the same time.. You wire some items in series, and some in parallel. not one item in both..

[B. Adams]

Originally posted by ctardi
If there is one thing in parallel, it is in series, unless it is parallel/series, which is what the op intended, but I missed the first time.

I really have absolutely no idea what you're trying to say here. No idea whatsoever...:confused:

[BGJAZZ]

Here's my general setup and explanations:

Powered mixer rated at 500watts/ch @ 4ohms (A-B)
4 Mains (125Watts @ 8ohms each)
4 Monitors (100watts @ 8ohms each)

Is there the possibility of using 4 mains into ch A and 4 monitors into ch B?

I'm no expert but I have a couple of reasons why I would use this type of setup.
A couple of bars we played were L shaped so I was thinking of pointing 2 speakers 1 way and the other 2 the other way.
I have smaller speakers so I don't have to carry the large ones.
If I only used 2 of the speakers, they wouldn't be rated high enough to handle 500 watts.
We're a 5 piece band so I thought 3-4 monitors would be good.
By not using a separate PA for the monitors, it's one less thing to carry, setup, cables and having enough power outlets (I'm suprised at the wiring of some bars. One place only had 1 outlet near the stage and we all had to make arrays of powerbars and extension cords).

I'm still learning...

[kayak]

BGJAZZ, what brand and model powered mixer are you using?

[boseengineer]

I would strongly recommend to not run anything in series unless you have a very good reason to.

Big Mike's little adapter will work fine but it will look to most users like a normal Y adapter and be used as such. The results of that may not be pretty.

The easiest way to address your problem is to simple leave two of your FOH speakers at home and run the remaining two in parallel (as always) from one channel. That certainly simplifies the setup and transport.

To answer the initial questions:
There is no way of wiring 4 8-Ohm speakers to get 4 Ohms.
Do not use the series/parallel wiring from your initial post Your suggested wiring would actually result in 6 Ohms, BUT you would be hitting the single "parallel" speaker with 250 Watt (probably frying it in the process) while the other three would only see about 28 Watt each.

[Craigv]

Originally posted by BGJAZZ
Here's my general setup and explanations:

Powered mixer rated at 500watts/ch @ 4ohms (A-B)
4 Mains (125Watts @ 8ohms each)
4 Monitors (100watts @ 8ohms each)

Is there the possibility of using 4 mains into ch A and 4 monitors into ch B?

I'm no expert but I have a couple of reasons why I would use this type of setup.
A couple of bars we played were L shaped so I was thinking of pointing 2 speakers 1 way and the other 2 the other way.
I have smaller speakers so I don't have to carry the large ones.
If I only used 2 of the speakers, they wouldn't be rated high enough to handle 500 watts.
We're a 5 piece band so I thought 3-4 monitors would be good.
By not using a separate PA for the monitors, it's one less thing to carry, setup, cables and having enough power outlets (I'm suprised at the wiring of some bars. One place only had 1 outlet near the stage and we all had to make arrays of powerbars and extension cords).

I'm still learning...


Well, this is one reason why it's important to plan your rig from the start whenever possible. It is, of course, not always possible.

Anyway, your possibilities are;

1. Run all 4 FOH in parallel. That's a 2-ohm load, and I'll bet my lunch your mixer won't handle that for more than a minute or two.

2. Run 2 FOH for a total load of 4 ohms. This matches the amp well, but;
a. It's less than ideal for the L-shaped bar.
b. The speakers handle 250w but you're providing them 500w. This isn't an immediate disaster, as many pros run 2x rated speker handling, but you have to be vewwwwwy careful.:D.

2B. Sell the 4 FOH speakers and buy two higher-power-handling and better-sounding speakers.

3. Drive yourself crazy by making a special cabling arrangement for series-parallel of all four FOH. 2-series paralleled with the other 2-series speakers would result in an 8-ohm load. I don't know what the amp is rated for at 8 ohms but it's likely to be no more than 300w. The lower power might be compensated somewhat by better dispersion in the L-shaped venues, or by coupling in normal venues if you pair speakers closely. I can guarantee the cabling will be a major pain in the ass....it'll have to be well-labeled, and it's a given that the cable will either be too short to fit some venues, or too long and piled up everywhere else.

4. Give up on the current arrangement. Use the powered mixer, both channels, to drive the monitors, and get power amp or amps that can drive the FOH properly.

[GCDEF]

Option 5 would be to buy another power amp to drive the additional speakers.

[Craigv]

Originally posted by GCDEF
Option 5 would be to buy another power amp to drive the additional speakers.

That's Option 4B. ;) :D