8 ohm 4ohm

[cider]

Hi all sorry but im back again.

Hope this will be a bit more straight forward then my last post.

I have 2 - 4 ohm speakers and 2 - 8 ohm subs running off a power amp.

My question is should I have them wired in a certain order to prevent damage to the amp?

I have tried various methods and the best sounding is running the subs off one channel and the other set off the other but am concerned this may cause problems.

The shop I bought them from said I should go from amp to speaker to sub.

Thoughts please.

[mostlyharmless]

Sorry, but to answer this we will need to know where the cross-over is?

[smalljoshua]

It sounds as if there is no Active Crossover in the Rig. Is this correct? Also What make and model are the speakers and Amps in Question?

 

We need more information to be able to help you.

 

Josh

[IRW]

It sounds as if there is no Active Crossover in the Rig. Is this correct? Also What make and model are the speakers and Amps in Question?

 

We need more information to be able to help you.

 

Josh

 

See Cider's previous post here for equipment models

[paulears]

You've a bit of a snag here. Usually wih this kind of kit the sub has a crossover built in that allows the low bass to run the sub and the higher band is split off to run the tops. Trouble is the spec I can find makes no mention that the subs have a crossover, so you have a number of solutions, none really good. You could simply run each channel to the subs and the tops - the sub wouldn't be able to handle the higher band anyway and would give some extra depth, but the impedance mismatch would mean the balance between the sub and the tops would be unpredictable and it would no doubt sound poo, and you could easily overdrive them. Option 2 would be to buy a crossover (place like CPC sell them) and stick it in the sub box. This is ok but would invalidate your guarantee. Thrid option is to buy another amp and a crossover like the cheap behringers - sonically this is the best option but at a cost probably higher than what you paid for the subs. The Peavey tops don't have an output for subs, so wierd the shop told you to connect them like this. The impedance mismatch means that power would not be evenly split between the tops and the sub - I'd guess that bass output from the subs would be far less than it could be.

 

You seem to have bought a strange combination - sorry.

[Rob_Beech]

My suggestion would be to get a crossover and amp and run the system 2 way. However this as Paul says this is an "expensive" option. Another option if the amp allows it would be to run a mono system with the tops on 1 side and the subs on the other. An active crossover would still be needed but not a second amp.

 

It's a bit of a cheap get out and I wouldn't recommend it as a GOOD option but it is a CHEAPER option. The amp must be 2ohm stable though. Alot of budget amps aren't. You do however have one thing on your side, it's the tops that are 4ohms not the subs. The subs often want a bit more power and whilst a higher impedance load is not going to get as much power from the amp, it's probably going to get more stable power than if it were running SUBS at 2ohms.

 

Rob

 

....Paul, did you mean to say "no doubt sound poor"?

[paulears]

I suspect I did, but reading back, I think the missing 'r' may just make better sense.

 

One thought for cider. It could be worth looking on the back of the amps - you didn't say which one, but a few do have a small switch that turns on a high cut filter, leaving just low bass - ideal for your subs. I fear that you do need to find a little more dosh to get something tweakable to give you at least some adjustment. If the shop sold you these as a matched system, could be worth asking them to sort it for you - because it isn't an ideal match.

[cider]

shame I didnt consult you guys before my purchase. I was sold this setup as a package and was somewhat concerned when I recieved the 4 ohm tops.

It was a spontaneous internet purchase (affter a few beers) to get some big sound together for a party and cant help but I think the guy from the store sold me some odments. Should get back to them if they really are not a match and will never run as a decent sounding setup?

I do also run the speakers from an nsm valve amp juke box which has a 4 ohm per channel amp and works ok.

This was another reason for buying some pa type speakers as I had blown 2 previous hi fi sets buy running them too loud for too long from the juke box.

I suppose what I would like to know is will I be better off if I got rid of the subs? get the store to change the amp or tops? or install crossovers ( excuse my ignorance I dont know what they are!).

The complete system gets very little use as most the time the tops are ran from the juke box and the amp is in storage.

Your thoughts are very much appreciated.

[paulears]

A crossover is a device that takes the full range audio from our system and splits it into two - the very low bas going to the subs, the rest to the tops. Your tops also have a crossover in them to split the bass from the treble. The ones in the tops handle speaker power, and are passive devices and are usually designed to split the signal at the frequency where the bass driver starts to lose it's performance, and the HF driver doesn't have any destructive amounts of bass present. If it tried to reproduce the bass it would almost certainly fail.

 

Subs normally have this splitting device fitted internally so the full range music goes to the sub - it takes the bit it needs and passed the remainder to the tops. This way all the cabinets are being given just wha they want, which is more efficient. I you have the luxury of more than one amp, you connect one amp to the tops, the other to the sbs and fed the amps via an active crossover - that normally has adjustment of where the crossover between sub and tops happens. This gives you much more control over the end sound.

 

I dare say that the system you have could work fine, IF you spend a bit more money. At the mo, driving the tops from the jukebox - does it sound ok? If you're happy, you could use the amp to power up the subs - they'll only be efficient at the bass end, so if you send them treble, you don't hear much of it - but they will respond to the bass. Not realy the best way to use them, but it might sound better than just the tops. Try it and see?

[Sound In Gloucestershire]

the warrior doesnt have any filters and is not recommended for 2 ohm use

 

personally id swap the amp for a more expensive peavey one (the PV1500 should be ok)

run one side full range into the two tops, 2 ohms is OK for this amp

then run the other side with the high filter on for the two subs

 

youd be putting 750 watts into the two peaveys (250w each) so dont destroy them, they do have cheap piezo horns in them

[AV Ian]

Ok, I'm a tad confused now. We're talking about Peavey pro 15's. Do we mean the plastic moulded PR15 or the Messenger Pro 15?

If we're talking messengers, I would suggest a pair of the matching messenger pro subs which have an active 2way crossover built in. So you cable amp -> sub -> top. The amp sees a 4 ohm load per channel, youre signal is split properly and you're using a nice matched system. An expensive option new maybe, but keep an eye on ebay, they often go really cheap.

Incidentally, if we are talking about Messenger Pro's, they are 350w rated and have a compression driver horn, perhaps the op could clarify his speaker model?

[Sound In Gloucestershire]

Ok, I'm a tad confused now. We're talking about Peavey pro 15's. Do we mean the plastic moulded PR15 or the Messenger Pro 15?

If we're talking messengers, I would suggest a pair of the matching messenger pro subs which have an active 2way crossover built in. So you cable amp -> sub -> top. The amp sees a 4 ohm load per channel, youre signal is split properly and you're using a nice matched system. An expensive option new maybe, but keep an eye on ebay, they often go really cheap.

Incidentally, if we are talking about Messenger Pro's, they are 350w rated and have a compression driver horn, perhaps the op could clarify his speaker model?

 

 

from his previous posts, they are the Messenger Pro Speakers, which depending on age are rated at 250w or 300w, either way, the horn is rather deceptive, they claim it to be a compression driver, when all the ones ive had to repair (over 10 different ones) have had a small plastic horn which you just throw away and replace, costs about £7, they blow really easily too!

 

Basically the original poster has 2 options, new subs or new amp

Personally id be on the phone to the dealer voicing my disgust at selling a total mismatch as a "Package" and making them sort it out

[AV Ian]

I stand corrected about power ratings, however both the pre 2005 and current Messenger Pro 15 are 4 ohm according to the Peavey website. The OP has stated in his previous post that his are 8 ohm.

That aside, I agree with you Pete, if it was sold as a package I'd be on the phone too.

[Sound In Gloucestershire]

in a past after that he states the tops are 4 ohm and the subs are 8 ohms

 

he needs to clarify which is correct before we can speculate any further

If they are 8 ohm tops, then I believe they originally did the Peavey Pro range in 4 and 8 ohms, but logically noone bought the 8 ohm versions and they were scrapped. Im thinking this shop saw him coming with this package? Clearing out a pair of speakers which potentially could be years old with a random pair of bass cabs that in no way match

[cider]

Im thinking this shop saw him coming with this package? Clearing out a pair of speakers which potentially could be years old with a random pair of bass cabs that in no way match

 

 

I think your right :D but I need to specifically tell them what is wrong with the mismatch and why!

anyone fancy quoting?