best way to connect speakers if not using subs

[psy]

just wondering. say for example im using a setup where the amp is rated 500wrms per channel into 4 ohm and the tops are rated 300wrms 4ohm and the subs are rated 250wrms 4 ohm and I decide due to doing something small I only want to use the tops with that amp would it be better or safer to connect both speakers to just one channel on the amp and use that or would I still be better to use both channels. I thought if I used one speaker on each channel I may be at greater risk of overdriving them. just curious cheers

[dunk_1984]

I'd say you were fine running just the tops off that amp and are under powering the speakers when running the subs as well.

[psy]

I'd say you were fine running just the tops off that amp and are under powering the speakers when running the subs as well.

 

funny I was wondering that myself as well although some places qoute the speakers as 250w rms and some 300. its not a set up I have yet it was just something I was wondering when I was looking at setups. I hear people talking about getting an amp that is more powerful than the speaker rating but I always thought that the logical assumption to the newbie unlearned like myself would be that if the amp was rated higher than the speakers it would be giving them too much and cause them to be overdriven. then again as somebody trying to learn not a lot seems to be what you would logically think when it comes to sound systems ;)

[sleah]

Hang on!

 

Are you saying the speakers are 4ohms per cab? If so unless your amp is rated down to 2ohms you will be overloading the amp when using all 4 cabs :o

If you meant per channel (i.e. 2 cabs together per side) then that's OK ;)

 

You will be fine just running the tops (assuming they are 8ohm cabs) as an amp that can drive 500w into 4 ohms will only do approx 350w in to 8ohm :)

[Rob_Beech]

Why?

 

With a properly designed passive network the impedance will remain pretty much consistent throughout the frequency range so will see the top cabs impedance (or there abouts) for frequencies within its working range (based on the passive networks design and parameters) and will see the subs impedance (or thereabouts) with low frequencies.

 

So the overall load will be around 4ohms.

 

 

I'm sure I've said that before today.... maybe I'm going mad.

[johndenim]

As Rob says it depends on the boxes what kit have you got OP?

 

I have worked out my 4 ohm tops together to be 2.6R linked (in series) but not counting reactance and other factors so I guess it would be slightly more.

Question.

 

Are cabs linked in series or parallel?

[Rob_Beech]

I'm guessing in parallel, funny wiring would be required to do series.

 

John, not sure how you get to your results. If you put both tops together in shunt then you'll have 2ohms. If you put them together with a 4ohm sub and a passive crossover (and we're talking the peavey boxes) you'll have a (approx) 4ohm load in total due to the nature of how the passive network works.

 

3 8ohm boxes in parallel makes a 2.66666 ohm load. or 1 8 and 1 4. But this is WITHOUT ANY passive crossovers in the equation.

 

Also, you mention series. It's unlikely your tops are linked in series. It would make them 1.3ohm cabinets, and unless you've got a stray bit of wire shorting out somewhere, this is unlikely.

 

 

Rob

[johndenim]

Well, you never know with peavey Rob, hehe.

 

My meter may be wrong as I measured in OMHS which I know is not the right way to do it.

 

I put my meter across 1+ and 1- with the 2 cabs linked

 

I bow to the master once again................ ;)

[Rob_Beech]

Passive resistance will read (normally) a little lower than the Impedance.

 

2.6 does seem a little lower than I'd expect. I'd have thought somewhere between 3 and 4 but who knows.

[psy]

right this is the set up I was looking at. I havent bought it as im still looking and what I end up getting will depend on what happens with the speakers I left into maplin.

 

1 x w audio warrior da-1000 amp

 

Technical Specifications:

 

Output Per Channel

Power Output (4 Ohms) 500W

Power Output (8 Ohms) 300W

Power Output (8 Ohms Bridged) 1000W

Frequency Response 10Hz - 25kHz

Signal to Noise Ratio 100dB

Slew Rate 50v/us

Damping Factor >300

THD @ Rated Power - 0.06% over rated bandwidth - 1kHz typically 0.03% - all models

Mains Input Voltage 240 V

Dimensions (mm) 483 x 88 x 420mm - 2U

Weight (kg) 15.0

 

2x peavey messenger pro subs

 

• 250 Watts RMS continuous, 500 Watts program, 1000 Watts peak
  
• 4 Ohms
  
• 15” (381mm) woofer
  
• Frequency response: 45 Hz - 300 Hz
  
• Efficiency: 98dB
  
• Two ¼’’ (6.35mm) jack and two Neutrik® Speakon® sockets
  
• High pass output for mid/high frequency satellite
  
• Resilient carpet covered
  
• Silver steel grille
  
• Satellite pole mounting
  
• Teardrop handles
  
• Made in the UK
  
• Dimensions: 19.9’’ (505mm)H x 26’’ (660mm)W x 19.1’’ (485mm)D
  
• Weight: 58.4lbs (26.5kg)
  

2x peavey messenger pro 15

 

300 watts RMS continuous 600 watts program 1200 watts peak

4ohms

15" woofer

1.75" (44mm) throat compression driver

dispersion 90° x 40°

freq response 50hz - 18hz

efficiency:98db

 

the only thing that even had me looking at this was that my local music shop was selling this package for £1010 (peavey amp instead of w-audio though) and I see it at whybuynew.co.uk for £550 so I was unsure whether it was a great deal from why buy new or whether my local music shop was charging extortionate prices (probably the latter) ;)

 

having studied the documentation for each of the individual items I had a few questions I was unsure of, one was answerd by rob which was if I was connecting a 4 ohm sub and a 4 ohm top to each channel would that not be presenting the amp with a 2ohm load but obviously its something to do with the way peavey designed the crossovers in them or something. my other questions were

 

1. if I connect a sub and a top into each channel should the slider on the amp be set to stereo or parallel to get the best from them (obviously not bridge, I thought parallel but was unsure)

2. I notice the amp has a input sensitivity selector and the choices are 1.44v, 1.0v and 0.775v. ive never seen this on any of the amps I have owned, how do I know what that needs to be set at?

3. if I dont get any money back off my stuff in maplin is this worth considering or is it no better than what I had?

 

sorry to keep asking what you may deem to be daft questions but its the only way I'll learn and I do appreciate the advice

 

**edit** I was looking online and noticed this part time course in my town its nothing too advanced but it may be helpful to me**edit**

http://www.hotcourses.com/uk-courses/Setti...81485/page.htm#

[Rob_Beech]

Your local music shop is selling it with a "better" amp, and new, and is a shop so has ever increasing overheads. Don't be too hard on them

[sleah]

1. if I connect a sub and a top into each channel should the slider on the amp be set to stereo or parallel to get the best from them (obviously not bridge, I thought parallel but was unsure)

2. I notice the amp has a input sensitivity selector and the choices are 1.44v, 1.0v and 0.775v. ive never seen this on any of the amps I have owned, how do I know what that needs to be set at?

 

1. Parallel is simply a 'mono' switch. It so you can feed a mono signal with needing a Y adaptor to feed both channels. Stereo would be the norm.

2. Depends on your mixer output. It is likely to be 1.0v or 0.775v

 

There is also 0.4v which is often labelled as 'record' out on a mixer.

 

Can't say I'm sure about 1.44v :unsure:

[psy]

Your local music shop is selling it with a "better" amp, and new, and is a shop so has ever increasing overheads. Don't be too hard on them

 

I know that mate and the word extortionate was used loosely but what I was meaning by it was simply was it a decent deal or was the shop overheads etc inflating the price and it really wasnt worth that. I suppose in short I was asking is it even worth considering or is it crap gear?

 

 

1. if I connect a sub and a top into each channel should the slider on the amp be set to stereo or parallel to get the best from them (obviously not bridge, I thought parallel but was unsure)

2. I notice the amp has a input sensitivity selector and the choices are 1.44v, 1.0v and 0.775v. ive never seen this on any of the amps I have owned, how do I know what that needs to be set at?

 

1. Parallel is simply a 'mono' switch. It so you can feed a mono signal with needing a Y adaptor to feed both channels. Stereo would be the norm.

2. Depends on your mixer output. It is likely to be 1.0v or 0.775v

There is also 0.4v which is often labelled as 'record' out on a mixer.

 

Can't say I'm sure about 1.44v :unsure:

 

thats helpful cheers I'll have to check the book that came with the mixer. its a djm600

 

**audio output 1.0v I take it thats the right thing im looking at?**edit**

[Rob_Beech]

Most probably.

 

It's certainly better than what you had, by some margin. Don't be fooled into thinking its tour grade stuff, it isn't, but its a step up and much more suitable to what you're doing.

 

The obvious answer to the voltage switch is the one that matches. The higher number you'll have to drive the desk harder to achieve maximum output on the amplifier. The lower one you'll over drive the amp easier. That all said. try all 3 and see which works best for your use.

[psy]

Most probably.

 

It's certainly better than what you had, by some margin. Don't be fooled into thinking its tour grade stuff, it isn't, but its a step up and much more suitable to what you're doing.

 

The obvious answer to the voltage switch is the one that matches. The higher number you'll have to drive the desk harder to achieve maximum output on the amplifier. The lower one you'll over drive the amp easier. That all said. try all 3 and see which works best for your use.

 

cheers rob. as for the voltage the mixer says 1.0v audio output in the documentation so I was thinking that woud be the safe bet.

 

as for the gear. yeah I wasnt expecting tour grade stuff at that price tbh and without getting the money back for the other gear that seriously narrowed my options as I dont have masses of money sitting here and getting a loan isnt so easy at the minute either with the current climate and the wife in my ear with a new baby due in may as well :unsure:

was I was actually thinking if I didnt get my money back from maplin was this

 

would it work if I used that peavey rig and also used the amp and 2 x 15's from maplin (likely with better drivers in them as im gonna have to fix one anyway maybe) all together.

 

its a lot of gear to be hauling if I had to but the place im playing would let me leave it there most likely so it would just be a case of setting it up each time.

 

which brings me to another question, my amp has ch1,ch2 output sockets below the inputs labelled link, so if I wanted to used 2 amps do I just link the second one to the first? by that I mean is the link just to send the signal on if you are using more than one amp or are there power issues that need to be considered? basically I was thinking the first amp powering the peavey rig and the second amp powering the 15's that I bought with that amp. in fact now I think about it if I had 2 amps there may be a better way to set it up using both to maximise the performance of the speakers I have. damn its confusing :** laughs out loud **: good job I applied yesterday for that wee course so I can learn the basics.

 

 

1 other thing all the stuff comes with the option of speakon or ¼" jack is there a benefit to changing all my leads to speakon from jack and using that?