New speakers help and ohms

[DJWilson]

Hi i wanted to get some new mackie speakers.

i never have understood ohms.

for example:- 2x250w amp at minium 4ohms.

and two speakers 400w at 8ohms.

how much power will i get out of them at a safe level for the speakers and amp.

and how do ohms work?

Thanks in advance.

[Excalibur]

Hi i wanted to get some new mackie speakers.

i never have understood ohms.

for example:- 2x250w amp at minium 4ohms.

and two speakers 400w at 8ohms.

how much power will i get out of them at a safe level for the speakers and amp.

and how do ohms work?

Thanks in advance.


That example would be a poor setup. 250w into 4Ohms means roughly 100/125w into 8Ohms, woefully inadequate for 400w speakers. There have been many posts concerning this, but as simply as I can:-

Ohms are a measure of what we will call resistance. ( Don't all the Technoheads start saying impedance, this is a beginners course! ) Therefore, more Ohms, less Watts. Less Ohms, more Watts. So obviously, lowest Ohms is the way to go, isn't it? Sadly no, because as the Ohms decrease, the heat output from your amp increases, so that 4Ohms may be regarded as the best compromise to avoid sending your amp to that great Disco in the sky.

Speakers tend to come in 4Ohms and 8ohms. Joining two pairs of 8Ohms in the normal manner ( Parallel. cables from amp to speaker, speaker to speaker) gives effectively 4Ohms, unlocking extra power from your amp.

Always compare RMS power figures, as it's the least worst method. Your amp RMS power output should probably be somewhere between same as and double that of your speakers.

So if your speakers are 400w RMS and 8 Ohms, your amp should give between 400 to 800w RMS into 8Ohms, and something like 600-1200w into
4Ohms.

That will do for now, bear in mind this is a very short simple treatise, It can get much more complicated, and argumentative.!

[Vectis]

So if your speakers are 400w RMS and 8 Ohms, your amp should give between 400 to 800w RMS into 8Ohms, and something like 600-1200w into
4Ohms PER CHANNEL.


Great explanation Excalibur! Just one thing worthy of note... in red.

[Excalibur]

Great explanation Excalibur! Just one thing worthy of note... in red.

Thank you, Sir.

[DJWilson]

ok so for example if i buy two 500w mackie speakers at 4ohms each and a 2x500w amp at minium of 4ohms. i will get 250w in each speaker?

im sorry bout being not much clue about this but i need to find out so i no what to buy in the future

Thanks so far

[DJWilson]

i was looking at a help site and from what ive just read. my conclusion is if i have a amp @ 4ohms and speakers @8ohms the speakers will do a quater of the power i.e. 400w @8ohms= 100w. depending on your amp.

if im wrong would you please be able to clear things up for me please.


Thanks in advance

[Excalibur]

i was looking at a help site and from what ive just read. my conclusion is if i have a amp @ 4ohms and speakers @8ohms the speakers will do a quater of the power i.e. 400w @8ohms= 100w. depending on your amp.

if im wrong would you please be able to clear things up for me please.


Thanks in advance

No, no ,and thrice no.:bang:

[Excalibur]

Right, let's have another go. The ohms aren't in your amp, ( not in the way you believe anyway) . The speaker system resistance determines what your amp delivers. Let's look at a Peavey PV2600, since it is close to the spec you asked for initially.


PV2600
Ref: 00512192) £ 449.00

Specifications
900 Watts RMS per channel into 4 Ohms, 550 Watts RMS per channel into 8 Ohms.
1800 Watts RMS at 8 Ohms bridged.
LED indicators for input signal, DDT™ and power.
2 built-in 150 Hz crossovers.
40 Hz low cut filter.
Volume control per channel.
Dual-speed fan with Turbo V-Cooling™ technology.
DDT™ speaker protection.
2U space rack.
Dimensions (HxWxD): 3.5'' (90mm) x 19'' (483mm) x 15.5'' (394mm)
Weight: 49lbs (22.25kg)

Disregard bridged altogether, that's degree level, and so far we're only at CSE. Now lets add the Mackie300z to this ( Later on Steve and I will tell you why not to buy these ;) :D )



Mackie 300z
AUDIO: ::
· Input Type: Speakon®-style NL4 jack 1/4-inch TS phone jack
· Input Impedance: 8 ohms
· Power Handling: (RMS) 300 watts, (peak) 750 watts


These are 8Ohms, ( each) so looking at the Peavey above, just after where it says Specifications we see this gives 550wRMS at 8Ohms( per side, or each since the amp is 2x 550w at 8 Ohms). 550 is 1.8 times bigger than 300, so it's in the range of same to twice as mentioned earlier. So far so good.

Most amps are Stereo, ( two channel, left and right. Forget The Labgruppen in a thread for Steve, and the big KAMs. That's postgraduate). When it says
2x a figure, it does exsactly what it says on the tin, ie two of them, one left, one right. 2x550w is 550w to the left channel, and 550w to the right channel.
Your Mackies are rated 300w RMS, that's each, and you have two of them, a left and a right. This is an ( expensive) example of a workable system.


However, save your hard-earned, and instead of the Mackies, get these.

http://www.class-d.com/Product.aspx?PRO=739

Better bass, a little bit quieter, but £200 cheaper per pair it would seem. That will go ever so far towards buying something like this to drive them

http://www.decks.co.uk/products/amps/behringer/EP2500.

Full system for the price of the Mackies alone. Nice.

[rob1963]

However, save your hard-earned, and instead of the Mackies, get these.

http://www.class-d.com/Product.aspx?PRO=739

Better bass, a little bit quieter, but £200 cheaper per pair it would seem.

You can actually get the Mackies for the same sort of price as the speakers in that link.

Also, I think the Mackies have a maximum SPL of 123db...a fair bit louder that the Class D, which are only 101db!

I only paid about £260 for mine.

When I was asking for advice about what speakers to replace my Warriors with & someone suggested Class D, I got several PMs from regulars advising against Class D!

[Corabar Steve]

When I was asking for advice about what speakers to replace my Warriors with & someone suggested Class D, I got several PMs from regulars advising against Class D! Don't knock 'em 'til you've tried 'em

[Excalibur]

You can actually get the Mackies for the same sort of price as the speakers in that link.

Also, I think the Mackies have a maximum SPL of 123db...a fair bit louder that the Class D, which are only 101db!

I only paid about £260 for mine.

When I was asking for advice about what speakers to replace my Warriors with & someone suggested Class D, I got several PMs from regulars advising against Class D!

That's list price. Someone on here recently paid below£160 for his Class-D's.

We can't all like the same things, otherwise life would get a bit boring!

[rob1963]

That's list price. Someone on here recently paid below£160 for his Class-D's.

We can't all like the same things, otherwise life would get a bit boring!

Fair enough, but I think there's a fair difference between a SPL of 101db & 123db.

[Excalibur]

Fair enough, but I think there's a fair difference between a SPL of 101db & 123db.

Agreed, but I'd like to see a sensitivity figure for the mackies, I can't seem to find one. Also, I just prefer 15" drivers for disco. One of these days someone is going to have to organise a(nother?) meet where we can comparatively test models/brands against each other.

[flatliners]

Don't knock 'em 'till you've tried 'em

thats exactly what i was gonna say about the rcf 310a

[Corabar Steve]

thats exactly what i was gonna say about the rcf 310a

But nobody's even mentioned them in this thread.

[Solitaire Events Ltd]

Well, I would still like to hear the Class Ds to make my own mind up.

[Corabar Steve]

Well, I would still like to hear the Class Ds to make my own mind up.

Any time you're in the area.

[Solitaire Events Ltd]

Any time you're in the area.

I have been in the area, but we ended up getting slaughtered instead! :beer1: :D

And not only once either...;)

[Corabar Steve]

Ask when you get here next time. :sj:

[Corabar Entertainment]

I have been in the area, but we ended up getting slaughtered instead! :beer1: :D

And not only once either...;)Yes, you keep leading us astray, don't you :p :p

[SPJ]

That example would be a poor setup. 250w into 4Ohms means roughly 100/125w into 8Ohms, woefully inadequate for 400w speakers. There have been many posts concerning this, but as simply as I can:-

Ohms are a measure of what we will call resistance. ( Don't all the Technoheads start saying impedance, this is a beginners course! ) Therefore, more Ohms, less Watts. Less Ohms, more Watts. So obviously, lowest Ohms is the way to go, isn't it? Sadly no, because as the Ohms decrease, the heat output from your amp increases, so that 4Ohms may be regarded as the best compromise to avoid sending your amp to that great Disco in the sky.

Speakers tend to come in 4Ohms and 8ohms. Joining two pairs of 8Ohms in the normal manner ( Parallel. cables from amp to speaker, speaker to speaker) gives effectively 4Ohms, unlocking extra power from your amp.

Always compare RMS power figures, as it's the least worst method. Your amp RMS power output should probably be somewhere between same as and double that of your speakers.

So if your speakers are 400w RMS and 8 Ohms, your amp should give between 400 to 800w RMS into 8Ohms, and something like 600-1200w into
4Ohms.

That will do for now, bear in mind this is a very short simple treatise, It can get much more complicated, and argumentative.!


I am in a similar boat in trying to get to grips with this too, and after reading this am more confused :confused:
This reads to me that I can have an amp with larger power output capabilities to my speakers at the same Ohm rating.
I currently have a pair of speaker rated at 250w each @ 8Ohm and need to consider what would be the max amp power I could use without popping the speakers. If I understand correctly above, I could use an amp of up to 500W per channel at 8Ohm? Surely this can't be the case??
Need to order a new amp this week so any help would be most useful.
Cheers

[Excalibur]

I am in a similar boat in trying to get to grips with this too, and after reading this am more confused :confused:
This reads to me that I can have an amp with larger power output capabilities to my speakers at the same Ohm rating.
I currently have a pair of speaker rated at 250w each @ 8Ohm and need to consider what would be the max amp power I could use without popping the speakers. If I understand correctly above, I could use an amp of up to 500W per channel at 8Ohm? Surely this can't be the case??
Need to order a new amp this week so any help would be most useful.
Cheers

There are three equally valid points of view to this, but yes, this can be perfectly acceptable. The theory is that if your amp is twice the power of your speakers, then you don't have to wind your amp up to max to get the sound you need. Thrashing an underpowered amp is a surefire recipe to blow part or all of your speaker system, whatever its rating.I run a pair of speakers from two different amps, one equal rating, one 50% higher. The one with 50% spare power runs them so much more easily, it's untrue.
Run a higher power amp into your speakers by all means, don't run it into the red at all, and in this case, don't run the amp at absolute full whack.;)

[Excalibur]

I am in a similar boat in trying to get to grips with this too, and after reading this am more confused :confused:
This reads to me that I can have an amp with larger power output capabilities to my speakers at the same Ohm rating.
I currently have a pair of speaker rated at 250w each @ 8Ohm and need to consider what would be the max amp power I could use without popping the speakers. If I understand correctly above, I could use an amp of up to 500W per channel at 8Ohm? Surely this can't be the case??
Need to order a new amp this week so any help would be most useful.
Cheers

This one's a runner.
http://www.decks.co.uk/products/amps/behringer/EP2500

Also

http://www.decks.co.uk/products/amps/c_mark/G098C
http://www.decks.co.uk/products/amps/kam/kxr_1000

[SPJ]

This one's a runner.
http://www.decks.co.uk/products/amps/behringer/EP2500

Also

http://www.decks.co.uk/products/amps/c_mark/G098C
http://www.decks.co.uk/products/amps/kam/kxr_1000

Thanks for the tips.
Does anyone have experience of the numark dimension 4? was looking at this too as a posible option.

[Excalibur]

Thanks for the tips.
Does anyone have experience of the numark dimension 4? was looking at this too as a posible option.

Personally no, but I think others on here rate it as a good piece of kit.

[mrdeejay]

Recently got a set of Peavey Pro 15" speakers and using a Mcgregor 500 watt mixer amp 250 watts a side.

Here are the spec of the speakers,


300 Watts RMS continuous, 600 Watts program, 1200 Watts peak
4 Ohms
15'' (381mm) speaker
1'' (25mm) Compression driver
Dispersion: 90° x 40°
Frequency response: 50 Hz - 22 kHz
Efficiency: 98dB
Two 1/4'' (6.35mm) jack and two Neutrik® Speakon® sockets
Full range with high frequency limiter
Resilient carpet covered
Silver steel grille
35mm steel top hat speaker stand adaptor insert
Teardrop handles
Made in the UK
Height: 25.6'' (650mm) Width: 18.1'' (460mm) Depth: 15.4'' (390mm) unpackaged
Weight: 48.5lbs (22kg) unpackaged


What would be the best amp to get if I was to replace what I have just now would it be another 500 Watt amp????

[Excalibur]

Recently got a set of Peavey Pro 15" speakers and using a Mcgregor 500 watt mixer amp 250 watts a side.

Here are the spec of the speakers,


300 Watts RMS continuous, 600 Watts program, 1200 Watts peak
4 Ohms
15'' (381mm) speaker
1'' (25mm) Compression driver
Dispersion: 90° x 40°
Frequency response: 50 Hz - 22 kHz
Efficiency: 98dB
Two 1/4'' (6.35mm) jack and two Neutrik® Speakon® sockets
Full range with high frequency limiter
Resilient carpet covered
Silver steel grille
35mm steel top hat speaker stand adaptor insert
Teardrop handles
Made in the UK
Height: 25.6'' (650mm) Width: 18.1'' (460mm) Depth: 15.4'' (390mm) unpackaged
Weight: 48.5lbs (22kg) unpackaged


What would be the best amp to get if I was to replace what I have just now would it be another 500 Watt amp????

Somewhere between 300-600w per channel at 4ohms.

For example, and choose your own supplier, as these may be cheaper elsewhere
http://www.djkit.co.uk/product.php?id=61&cat=44

http://www.djkit.co.uk/product.php?id=82&cat=44

Low cost
http://www.djkit.co.uk/product.php?id=92&cat=44

Bit bigger

http://www.djkit.co.uk/product.php?id=102&cat=40


If you intend to upgrade, it would be permissible to get more powerful models of the above, and use with care.

[djsteve10]

I see alot of you reccomend Class D speakers then?
Lots of high reccomendations for mackie too... ive heard mackie and they sound nice just got to hear a set of class D's... the idea is my younger brother is getting into dj'in and sound for his school so i am going to hook him up with a nice Pa to get him started off.

[rob1963]

I see alot of you reccomend Class D speakers then?


And to be fair, a lot of forum members DON'T recommend Class D speakers.

When I recently replaced my Warriors, I asked for suggestions here.

As soon as someone mentioned Class D, I had several PMs from other members suggesting I did NOT get Class D!

[Tom]

i bet Excalibur must be getting really bored of talking about speakers on every thread going at the moment. lol


sorry for going off topic if it did.

[Excalibur]

i bet Excalibur must be getting really bored of talking about speakers on every thread going at the moment. lol


sorry for going off topic if it did.

Mindreader!;)