Can I Replace My 8 ohm woofer with a 4 ohm woofer??
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sure u can, just make sure its the same size...lol...nah, u can, but there are things u have to consider, like...how/what are u using to power this sub? how is it set up in ur system? does this sub have a pair? and so on, so just fill us in on those and it should be easier to answer ur question.
you also have to make sure that your amp for the sub won't burn out the 4 ohm speaker if its been drivin' a 8 ohm speaker b/c of the difference in the load size from the speaker (i think i know what i just said but right now i'm tired and i have to wake up early tomorrow to go to school)
k i have 4 cabnits each one has a 12in sub, mid, horn, i am replaceing all 4 of the subs
Why are you replacing the speakers? If they are blown get them re-coned instead of changing them, unless exact replacement. If the speakers are a brand name chances are the cabinet is matched to the parameters of the speaker in them. Also the Xover takes into account the frequency response of the speaker.
OK DJ JESS...SUB REPLACEMENT 101 IS IN SESSION
Sure you can replace your 8ohm speaker with a 4ohm. The question is why are you replacing it with a 4ohm instead of an 8ohm?
First thing is the box is built and tuned to the original speakers that are in there. This means by changing the woofer you may notice that the sound isnt as good or that you dont hear much of a difference. The sizes of the box were calculated using the specs of the original speaker to get the most optimal sound. Basically you have a 50 50 chance.
Next by changing 8ohms to 4ohms you now have tot hink about how these will be hooked up to your amplifier. If you have a professional amplifier then you do not have to do much. If not then you could be setting yourself up for disaster. (this is getting long but....read below
\/ \/
Ohms law..2 8ohm boxes in parallel = 4ohms total
parallel = 2 boxes on one channel of an amplifier
..........2 4ohm boxes in parallel = 2ohms total
If your amp is not rated for 2ohm stereo operation then you wil screw yourself (blown woofers or amp) until you buy an amp that can.
If your amp canhandle 20hm stere operation then you just have to remember that most amps when bridged can drive a minimum load impedance of 4ohms which would mean you should only put one speaker on the amp when bridged as opposed to 2 8ohms
Also as someone mentioned, the cross over has been tuned based on the specs on the original factory woofer.
Tell me why you want to change these speakers and I can give you advice.
Sure you can replace your 8ohm speaker with a 4ohm. The question is why are you replacing it with a 4ohm instead of an 8ohm?
First thing is the box is built and tuned to the original speakers that are in there. This means by changing the woofer you may notice that the sound isnt as good or that you dont hear much of a difference. The sizes of the box were calculated using the specs of the original speaker to get the most optimal sound. Basically you have a 50 50 chance.
Next by changing 8ohms to 4ohms you now have tot hink about how these will be hooked up to your amplifier. If you have a professional amplifier then you do not have to do much. If not then you could be setting yourself up for disaster. (this is getting long but....read below
\/ \/
Ohms law..2 8ohm boxes in parallel = 4ohms total
parallel = 2 boxes on one channel of an amplifier
..........2 4ohm boxes in parallel = 2ohms total
If your amp is not rated for 2ohm stereo operation then you wil screw yourself (blown woofers or amp) until you buy an amp that can.
If your amp canhandle 20hm stere operation then you just have to remember that most amps when bridged can drive a minimum load impedance of 4ohms which would mean you should only put one speaker on the amp when bridged as opposed to 2 8ohms
Also as someone mentioned, the cross over has been tuned based on the specs on the original factory woofer.
Tell me why you want to change these speakers and I can give you advice.
McGyver,
Pay attention, class is now in session...
If you were to replace the bass drivers the nominal impedance load for just the frequencies that driver covers are affected. On average, or the nominal load for the entire frequency range of the cabinet may only slightly be lowered depending upon the true measured impedance of the new drivers.
Further, there really is no set impedance as impedance is frequency dependent...meaning it varies greatly. Many speakers can range from 2^ to as high as 20^.
As for the formula for determining nominal loads please take note:
Z = resistance (or load)
Z1 X Z2 divided by Z1 + Z2 = Z
I'll be expecting an apple next session McGyver...
Personally, I woud contact the manufacturer about a replacement speaker, or get the specs of the original drivers and call Eminance to see what they have that matches up well. A 50-50 chance isn't even close really, I suspect randomly throwing drivers in that cabinet gives you a 1 in 10 chance of even equaling the original performance.
Bob Dietrich
Pay attention, class is now in session...
If you were to replace the bass drivers the nominal impedance load for just the frequencies that driver covers are affected. On average, or the nominal load for the entire frequency range of the cabinet may only slightly be lowered depending upon the true measured impedance of the new drivers.
Further, there really is no set impedance as impedance is frequency dependent...meaning it varies greatly. Many speakers can range from 2^ to as high as 20^.
As for the formula for determining nominal loads please take note:
Z = resistance (or load)
Z1 X Z2 divided by Z1 + Z2 = Z
I'll be expecting an apple next session McGyver...
Personally, I woud contact the manufacturer about a replacement speaker, or get the specs of the original drivers and call Eminance to see what they have that matches up well. A 50-50 chance isn't even close really, I suspect randomly throwing drivers in that cabinet gives you a 1 in 10 chance of even equaling the original performance.
Bob Dietrich
dietrich i have no problem giving you an apple as I was probably tired when i responded to this and there are one or two typos.quote:Originally posted by Bob Dietrich:
[qb] McGyver,
Pay attention, class is now in session...
If you were to replace the bass drivers the nominal impedance load for just the frequencies that driver covers are affected. On average, or the nominal load for the entire frequency range of the cabinet may only slightly be lowered depending upon the true measured impedance of the new drivers.
Further, there really is no set impedance as impedance is frequency dependent...meaning it varies greatly. Many speakers can range from 2^ to as high as 20^.
As for the formula for determining nominal loads please take note:
Z = resistance (or load)
Z1 X Z2 divided by Z1 + Z2 = Z
I'll be expecting an apple next session McGyver...
Personally, I woud contact the manufacturer about a replacement speaker, or get the specs of the original drivers and call Eminance to see what they have that matches up well. A 50-50 chance isn't even close really, I suspect randomly throwing drivers in that cabinet gives you a 1 in 10 chance of even equaling the original performance.
Bob Dietrich [/qb]
As far as impedance goes, yes i know impedance varies with frequency, hence the term impedance and not resistance. Yes I know that the impedance varies with the particular box the woofer is in due to a mechanical impact on the impedance of the box. And yes I also know that as the party goes on we have an increase in heat in the woofers as well as the wires wbich we all know leads to an increased impedance which then leads to something that we call "power compression." Yes we know all this good stuff but I felt it was beyond the scope of this post. You dont want people to get confused since the applications and results they are trying to recieve are not that serious.
and dietrich Z does not equal resistance but rather impedance, Im sure you were tired too and over looked that part of your post
Like I said dietrich we can get into a lot of details but I tried to make it as simple as possible so that they can understand a little something. Thnx for pointing some things out
so ur calling us dumb??...quote:Originally posted by McGyver:
[qb]
Like I said dietrich we can get into a lot of details but I tried to make it as simple as possible so that they can understand a little something. Thnx for pointing some things out [/qb]
juss kiddingby the way....great stuff guys
Actually, Z DOES equal resistance. If the impedance varies, so shall the resistance...basic 101 stuff here, nothing groundbreaking.
As for explaining things, I wasn't aware I was going over the top, I try to keep things very simple and easy to read/understand. From the numerous emails I receive thanking me for advice and further advice, I had hoped it was working. We could get into a really hot thread on advanced electrical theory or even fluid dynamics which all relates to sound...fun stuff to be sure, but not a very good read...and FYI, you can just call me Bob...
As for explaining things, I wasn't aware I was going over the top, I try to keep things very simple and easy to read/understand. From the numerous emails I receive thanking me for advice and further advice, I had hoped it was working. We could get into a really hot thread on advanced electrical theory or even fluid dynamics which all relates to sound...fun stuff to be sure, but not a very good read...and FYI, you can just call me Bob...
Yes....Listen to Mr Dietrich. Actually he's been an audio Einstein longer than I have been alive. Of course he is human and CAN make mistakes, and I don't always agree with him. Anyway he is a great guy, and has forgotten more than most of us will ever know about audio, even me....the Audio gear junkie.
<<==shakes bob's hand.quote:Originally posted by Bob Dietrich:
[qb] Actually, Z DOES equal resistance. If the impedance varies, so shall the resistance...basic 101 stuff here, nothing groundbreaking.
As for explaining things, I wasn't aware I was going over the top, I try to keep things very simple and easy to read/understand. From the numerous emails I receive thanking me for advice and further advice, I had hoped it was working. We could get into a really hot thread on advanced electrical theory or even fluid dynamics which all relates to sound...fun stuff to be sure, but not a very good read...and FYI, you can just call me Bob...
hot thread could get boring very easily....lol
fluid dynamics not my arena...i'll leave that to you. Advanced electrical theory gets kinda boring when you start getting into all the math dont u think? Atleast I do.
Maybe you can answer a question for me bob
-amplifier has played and played fine over a few years and all of a sudden stopped working in the middle of getting a signal.lights come fan doesnt come on...even when the unit is run into clipping, but there is no output. My guess is the output transistors. Any ideas? Havent gotten a chance to check out the unit yet since guess what else seems not to work right now...my meter ha go figure
Sorry,
Haven't been back here for awhile, but I doubt the outputs went out noiselessly (is that a word? ). Also, the fan isn't working which probably wasn't working before the unit came up lame...and could well be the very cause. As for the lights still working, that depends upon where the meter gets the signal from, likely the input side...which leads me to believe you've likely had the unit in for repairs by now. Without putting it on the bench there's really no way of knowing...and one doesn't even know the kind of amp we're talkingabout here, but I suspect the finals are probably ok if the sound simply just "stopped working" without any audible clues of distress. Of course that's just a hunch... 
Haven't been back here for awhile, but I doubt the outputs went out noiselessly (is that a word?
). Also, the fan isn't working which probably wasn't working before the unit came up lame...and could well be the very cause. As for the lights still working, that depends upon where the meter gets the signal from, likely the input side...which leads me to believe you've likely had the unit in for repairs by now. Without putting it on the bench there's really no way of knowing...and one doesn't even know the kind of amp we're talkingabout here, but I suspect the finals are probably ok if the sound simply just "stopped working" without any audible clues of distress. Of course that's just a hunch...