View Full Version : I dont understand
I have seen this many times but dont know how its done.
I have seen some speaker setups where there are 4 speakers and 1 amp or 6 speakers and 1 amp.
Class-D do a 6 speaker setup with one amp. How can this be done and still provide 750 watts per side for example.:confused:
spin mobile disco
06-09-2007, 08:59 PM
Most amps are designed to work at 8 ohms resistance each side at a given wattage. For example you said 750 watt per side, lets assume that it is at 4 ohms. The resistance has no gone down to 4 ohms per side meaning that the amp had less effort to power the speakers. Now most amps when taken down to 4 ohms will provide more power for example my amp in 4 ohms provides 620 watts rms per channel but only 400 watts at 8 ohms.
I use a single amp to provide power for 4 x 8 ohms speakers. This gives them 300 watts rms each at 4 ohms.
Works well.
im sorry but can you make it bit more simpler for me to read because it's a bit to hard for me to read. :(
Excalibur
06-09-2007, 09:29 PM
im sorry but can you make it bit more simpler for me to read because it's a bit to hard for me to read. :(
Firstly google Ohms law. This is a good starting point.
Secondly, in easy terms, speakers in parallel = lower impedance. 2 eight ohms in parallel = 4 ohms. This is a good arrangement, as many speakers to move air, and more power achieved as, for our purposes, amps deliver most power at 4 ohms. ( All people who run at 2 ohms, we know you exist, but lets pretend for now)
Subs and tops are slightly different, if using built in crossovers, they can be regarded as one pair, not two, as they get the impedance from the main drivers. ( In Class-D usually eight).
So, the subs and tops can be regarded as one pair of eight ohm speakers, and the full range speakers are another eight ohm pair in parallel with them, thus four ohms, Voila. ( Amp feeds full range in parallel with subs. Subs feed tops from crossover. Amp gives 750w per side at 4ohms, so 375w into each full range and 375w into combined subs and tops. 4x375w = 1500w )
Don't even ask about bridging, or active crossovers, I've had a hard day!:bang:
DJWayne
06-09-2007, 09:47 PM
I have seen this many times but dont know how its done.
I have seen some speaker setups where there are 4 speakers and 1 amp or 6 speakers and 1 amp.
Class-D do a 6 speaker setup with one amp. How can this be done and still provide 750 watts per side for example.:confused:
It all depends on what the amp is capable of you need to understand the specifications of the speakers and the amp together to know what you can run and what you cant.
To try and simplify a little what excalibur has said.
Speakers have what they call impedence ratings and amplifiers supply different power levels at different impedence levels.
Speakers are usually 8ohm or 4ohm
When wiring them up in paralel i.e in to one speaker then out to the next etc. you have to work out what the impedence will be to see if the amp can take it.
To give you some simple examples if you are using 8ohm speakers and you have 4 of them 2 per channel you will end up with 4ohm at the amp.
It works out like this impedence of speakers divided by the number of speakers = the impedence at the amp per channel.
As long as you impedence at the amp is not lower than the rating of the amplifier you will be ok. :)
Firstly google Ohms law. This is a good starting point.
Secondly, in easy terms, speakers in parallel = lower impedance. 2 eight ohms in parallel = 4 ohms. This is a good arrangement, as many speakers to move air, and more power achieved as, for our purposes, amps deliver most power at 4 ohms. ( All people who run at 2 ohms, we know you exist, but lets pretend for now)
Subs and tops are slightly different, if using built in crossovers, they can be regarded as one pair, not two, as they get the impedance from the main drivers. ( In Class-D usually eight).
So, the subs and tops can be regarded as one pair of eight ohm speakers, and the full range speakers are another eight ohm pair in parallel with them, thus four ohms, Voila. ( Amp feeds full range in parallel with subs. Subs feed tops from crossover. Amp gives 750w per side at 4ohms, so 375w into each full range and 375w into combined subs and tops. 4x375w = 1500w )
Don't even ask about bridging, or active crossovers, I've had a hard day!:bang:
i understood that a bit better. cheers. ill check it out
if im right, bridging is where L+R = 1 mono output. Not very good because the amp can burn out quicker:confused:
active crossover is there you can controll what frequency goes to each speaker. eg, sub will only get 30-120 and top as 120-18000 as an example???
bought some books from studiospares. i find it hard to read but these i understand. :lol:
It all depends on what the amp is capable of you need to understand the specifications of the speakers and the amp together to know what you can run and what you cant.
To try and simplify a little what excalibur has said.
Speakers have what they call impedence ratings and amplifiers supply different power levels at different impedence levels.
Speakers are usually 8ohm or 4ohm
When wiring them up in paralel i.e in to one speaker then out to the next etc. you have to work out what the impedence will be to see if the amp can take it.
To give you some simple examples if you are using 8ohm speakers and you have 4 of them 2 per channel you will end up with 4ohm at the amp.
It works out like this impedence of speakers divided by the number of speakers = the impedence at the amp per channel.
As long as you impedence at the amp is not lower than the rating of the amplifier you will be ok. :)
i actually got that. i also think that is a speaker is 100 watts at 8 ohm and another speaker 100 watts at 2 ohm, the 2 ohm will be louder?
DJWayne
06-09-2007, 09:57 PM
No a speaker capable of 100 watts is only capable of 100 watts no matter what the impedence it just means the amp deosnt have to work as hard to get to 100 watts.
To give you an idea here are the specs of my amp and how much power it puts out at different loads
STEREO MODE, Both Channels Driven per channel
8 ohms 700 W (tops speakers only)
4 ohms 1100 W (subs and tops)
2 ohms 1700 W
ahh. ok. i should be been taught this at college but all they wanted to do was record in the studio and do live sound. all they said was plug it in and thats it. i know how to wire everything up just not the theory side of it, if you get me :(
PropellerHeadCase
06-09-2007, 11:56 PM
Think of impedance (literally to impede, to resist, hence also resistance) as the brakes on the output of your amp - the lower the impedance the less braking there is in place the louder you will be (however briefly) and the more chance that your amp will spin-out and crash (chavs optional).
You can also think of the maths behind 8ohms and 4ohms as like that of water (power) going through a hose-pipe (amp and speaker wiring)...
If you turn the tap on at mains pressure with a single hose attached you get water coming out of the hose at mains pressure (once the hose itself is full). If you attach a splitter to the tap and have two hoses pushing water out at now slightly less than mains pressure (though the difference is likely to appear negligible) you have what appears to be twice the power because the water is now able to go down one of two hoses (we know that water chooses the path of least resistance so now it has the choice of two paths).
It gets more complicated when speakers are in series, but I think that analogy very basically works.
Think of impedance (literally to impede, to resist, hence also resistance) as the brakes on the output of your amp - the lower the impedance the less braking there is in place the louder you will be (however briefly) and the more chance that your amp will spin-out and crash (chavs optional).
You can also think of the maths behind 8ohms and 4ohms as like that of water (power) going through a hose-pipe (amp and speaker wiring)...
If you turn the tap on at mains pressure with a single hose attached you get water coming out of the hose at mains pressure (once the hose itself is full). If you attach a splitter to the tap and have two hoses pushing water out at now slightly less than mains pressure (though the difference is likely to appear negligible) you have what appears to be twice the power because the water is now able to go down one of two hoses (we know that water chooses the path of least resistance so now it has the choice of two paths).
It gets more complicated when speakers are in series, but I think that analogy very basically works.
that makes sence. :lol: just need to put it into pratice.
i have found a some speakers that are 500 watts rms at 8 ohm. now the amp i looking at is 1025 watts per side at 4 ohm. if i get 4 of these speakers and have 2 per side that would make them 4 ohm then giving 1000 watts rms perside. and because the amp is 1025 i whould get slightly better sound because the amp is not running at full wack.
am i on the right track or still getting it wrong. lol
DJWayne
07-09-2007, 12:16 AM
Yep i think you may have cracked it :)
cool. still going to do some research so at least i know what i am talking about. thanks for all your help everyone. :d
Excalibur
07-09-2007, 07:22 AM
Think of impedance (literally to impede, to resist, hence also resistance) as the brakes on the output of your amp - the lower the impedance the less braking there is in place the louder you will be (however briefly) and the more chance that your amp will spin-out and crash (chavs optional).
You can also think of the maths behind 8ohms and 4ohms as like that of water (power) going through a hose-pipe (amp and speaker wiring)...
If you turn the tap on at mains pressure with a single hose attached you get water coming out of the hose at mains pressure (once the hose itself is full). If you attach a splitter to the tap and have two hoses pushing water out at now slightly less than mains pressure (though the difference is likely to appear negligible) you have what appears to be twice the power because the water is now able to go down one of two hoses (we know that water chooses the path of least resistance so now it has the choice of two paths).
It gets more complicated when speakers are in series, but I think that analogy very basically works.
Well done that man, excellent analogy.
Excalibur
07-09-2007, 07:27 AM
that makes sence. :lol: just need to put it into pratice.
i have found a some speakers that are 500 watts rms at 8 ohm. now the amp i looking at is 1025 watts per side at 4 ohm. if i get 4 of these speakers and have 2 per side that would make them 4 ohm then giving 1000 watts rms perside. and because the amp is 1025 i whould get slightly better sound because the amp is not running at full wack.
am i on the right track or still getting it wrong. lol
Now because we are lovely folk on here, we won't now start the debate on whether your speakers should be same capacity as your amp, double or half!
It usually ends up as handbags at twenty paces!
Yes you are definitely on the right track, sounds a viable rig.
Now because we are lovely folk on here, we won't now start the debate on whether your speakers should be same capacity as your amp, double or half!
It usually ends up as handbags at twenty paces!
Yes you are definitely on the right track, sounds a viable rig.
this speaker setup was just an example just to get my head around it. if anyone wants to have a moan at me then feel free too. kind of used to it now anyway. i think some of you are really nice people but i think some of you lot think im such a Expletive Removed and dont know anything. well i dont know everything and im here in the first place to gain more infomation needed for this industry. Anything Live Sound i know (mostly eletrical equipment, outboard) but no one knows everything. anyway..................and relax
Excalibur
07-09-2007, 06:02 PM
this speaker setup was just an example just to get my head around it. if anyone wants to have a moan at me then feel free too. kind of used to it now anyway. i think some of you are really nice people but i think some of you lot think im such a Expletive Removed and dont know anything. well i dont know everything and im here in the first place to gain more infomation needed for this industry. Anything Live Sound i know (mostly eletrical equipment, outboard) but no one knows everything. anyway..................and relax
Plenty of us on here still have a lot to learn! Some of us just don't realise it! :p
Seriously, a day without learning is a day wasted. No matter how long you do this job, you should never stop learning. Over thirty years, and I still haven't seen it all:eek:
Excalibur
07-09-2007, 06:04 PM
well i dont know everything and im here in the first place to gain more infomation needed for this industry.
The first step in learning is to realise how little you know.
Stay here and you will learn............................................. ...
not to use textspeak, not to call Tamla Motown a genre, not to say how your Skytech speakers are better than active Mackies, not to call people wusses when they say their Peaveys are too heavy, etc,etc!
Doddle, really!
the thing is that i do like to learn new things but only if i am intrested in it, like dj'ing. Even thought i have trouble reading i have bought books to try and increase what i know and understand what other people are saying. it just takes time
ok, more questions.
i take it that if you have two 4 ohm speakers then that could make 2 ohm???
what about if you have three 8ohm speaker (tri-amp) all running off one channel or in bridge mode. what would be the outcome of ohm's here???
ok, more questions.
i take it that if you have two 4 ohm speakers then that could make 2 ohm???
A 2 OHM LOAD, CORRECT
ok, more questions.
what about if you have three 8ohm speaker (tri-amp) all running off one channel or in bridge mode. what would be the outcome of ohm's here???
A 2.6 OHM LOAD
Excalibur
11-09-2007, 08:22 PM
ok, more questions.
i take it that if you have two 4 ohm speakers then that could make 2 ohm???
what about if you have three 8ohm speaker (tri-amp) all running off one channel or in bridge mode. what would be the outcome of ohm's here???
Careful, my friend. I can smell the amps burning from here! As others have said previously, this is a very dangerous arrangement, as Propeller said, " no brakes". Unless you have really top end gear, and top end knowledge, four ohms is best regarded as lowest usable impedance.
just out of intrest how would you rate DAP Audio. Im looking at these 2 speaker
Speaker - http://highlite.omc.net/index.php/highlite/silver.econtent/catalog/highlite/dap_audio/speakers/x_series/x_15
Bass Bin - http://highlite.omc.net/index.php/highlite/silver.econtent/catalog/highlite/dap_audio/speakers/x_series/x18b
i was thinking of have 4 bins and 2 tops but have the 2 subs her side hooked together per side in bridge mode (8+8=4 ohm) and the tops run in stereo (8ohm)
Excalibur
11-09-2007, 08:41 PM
just out of intrest how would you rate DAP Audio. Im looking at these 2 speaker
Speaker - http://highlite.omc.net/index.php/highlite/silver.econtent/catalog/highlite/dap_audio/speakers/x_series/x_15
Bass Bin - http://highlite.omc.net/index.php/highlite/silver.econtent/catalog/highlite/dap_audio/speakers/x_series/x18b
i was thinking of have 4 bins and 2 tops but have the 2 subs her side hooked together per side in bridge mode (8+8=4 ohm) and the tops run in stereo (8ohm)
If I understand correctly, I feel you may have used a term wrongly.
Four subs would be 4ohms per side with two per side IN PARALLEL. Bridged is what you do to the amp, and would probably be bad news into a 2ohm load.
If I understand correctly, I feel you may have used a term wrongly.
Four subs would be 4ohms per side with two per side IN PARALLEL. Bridged is what you do to the amp, and would probably be bad news into a 2ohm load.
sorry. i was ment to say that would be an amp per side for each pair which would make it four ohm. so three amps in total
Excalibur
11-09-2007, 09:34 PM
sorry. i was ment to say that would be an amp per side for each pair which would make it four ohm. so three amps in total
Quite right, your terminology is correct, as the bass amps would be bridged, feeding 4ohm loads ( two 8ohm in parallel), no probs.:)
TonyB
11-09-2007, 11:12 PM
Quite right, your terminology is correct, as the bass amps would be bridged, feeding 4ohm loads ( two 8ohm in parallel), no probs.:)
Apart from in bridged mode, each channel of the amp would be running at 2 ohms so in effect is the same as running the amp at 2 ohms. Would be better to run each speaker of a single channel.
sleah
12-09-2007, 09:12 AM
Are we sure everyone is speaking the same language here?
The term "bridge" seems to have been fuzzed a little.
Bridging an amp is configuring a two channel amp to be one channel, the speakers are wired across the two positive outputs. Most amps seem to only drive 8ohms bridged mode, but some may do 4 but less likely.
There isn't such thing as bridging speakers, they are either running in series or parallel.
Can we clear this up, as KMA could be in danger of frying his amps:eek:
Larry B Entertainment
12-09-2007, 03:31 PM
Can we clear this up, as KMA could be in danger of frying his amps:eek:
If anyone hears a loud bang, its just KMA blowing up his speakers :eek:
Excalibur
12-09-2007, 08:15 PM
Are we sure everyone is speaking the same language here?
The term "bridge" seems to have been fuzzed a little.
Bridging an amp is configuring a two channel amp to be one channel, the speakers are wired across the two positive outputs. Most amps seem to only drive 8ohms bridged mode, but some may do 4 but less likely.
There isn't such thing as bridging speakers, they are either running in series or parallel.
Can we clear this up, as KMA could be in danger of frying his amps:eek:
Just picked this as an example
Amplifier Alto Mac 2.3 DJ equipment or Band PA audio system
£239.00
What do we expect from a professional power amplifier? Reliability, hi-fi quality, high performance and durability! These amplifiers were designed to meet all the requests of audio professionals around the world! You can find a solution to suit your needs at the best possible price with the MAC2 series.
RMS(EIAJ) power: 2 x 360W@ 8Ω; 2 x 720W@ 4Ω; 2 x 1200 @ 2Ω; 1 x 1350w @8Ω; 1 x 1600W@ 4 Ω
Have to admit I was unsure about this, which is why I checked. Running this bridged into 4ohms gives approx 1.6Kw, and with two amps thus fitted, 3.2Kw
One amp at 4 ohms per side would only give 1.4Kw.
ok.
i want to run 2 subs of one amp in bridge mode.
the amp is the Numark Dimension 3.
http://www.djkit.co.uk/acatalog/amps_numark.html
In bridge mode its 1300 watts rms in 4 ohm. we know that two 8 ohm speakers makes 4 ohm and the speaker are 600 watts each which gives us a total of 1200 watts rms. a slightly bigger amp means i can turn it up and not get distortion form the speakers. they will just blow instead but i wouldnt want to turn them all the way up as there will be 4 subs altogether.
so i would get 2 amps for the subs. 1 amp per pair, per side and one more amp to run the tops in normal stereo (speakers being 500 watts rms, 8 ohm each and only having 2)
Vectis
12-09-2007, 08:46 PM
Blimey... that's some serious gigs you must be planning there ;)
Most of my gigs (up to 200ish folks) only need one sub; bigger halls and outdoor I use two.
Excalibur
12-09-2007, 08:55 PM
Apart from in bridged mode, each channel of the amp would be running at 2 ohms so in effect is the same as running the amp at 2 ohms. Would be better to run each speaker of a single channel.
I have had to do some thinking about this, and technically we are both right. You are undoubtedly completely correct in what you say. I was also correct in saying that it was possible/.permissible ( granted not with every amp), but I was at fault in not saying clearly that it was not good practice.
KMA: The Numark would give you 1300w at 4ohms bridged. A safer, and in many people's eyes ( mine included) is simple. Get a bigger amp!!!!! There are amps at close to the price of the Dimension3 which will give over 500w per channel into 8ohms. Not quite as powerful, but safer. Now let's start the argument about which budget amp is reliable/nice sounding!:sofa:
i could have my own mini download festival. :lol:
i need a big pa system as i want to band pa. more like of about 1000 people if a 3.4k system can handle if and if not then ill double it and have a 6.8k but thats a little while off yet.
all i need at the moment is a really good subwoofer to which i can add to and have a sound system all the same make but it has to be passive and road proof so if i do outside gigs then the amps can be by me and i can just put a plastic cover over the speakers.
plus if i have a disco all i would need would be are the tops and maby a sub if needed
Vectis
12-09-2007, 09:22 PM
Gotcha! :cool:
ogt my price list for everything. just need all this money to buy everything now. :(. but my main thing is sub and amp. total of £600
Excalibur
12-09-2007, 09:49 PM
ogt my price list for everything. just need all this money to buy everything now. :(. but my main thing is sub and amp. total of £600
Go see Class-D. Two subs, two tops, one amp 1300w total, £620 list price. What more could you ask for?
could do. there is a new thread so this one dont go off topic. cheers.m ill have a look. :)
i know this if off topic but i just checked how long it would take me to go up to class-d and it would take me about 3 hours. 174.1 miles. just a tad bit to far for me but if people say that there good speakers then ill have to take there word or unless anyone lives in then kent area where i could have a listen then kool but there is no way im going up there just to listen to speaker for an hour. i think ill be going for them looks like it :sofa:
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