i need some educating on speaker cabs

  • Thread starter Thread starter treymonfauntre
  • Start date Start date
and i have to play a show tomorrow and only have about a hundred bucks to blow on speakers :(
unless my friend will let me borrow his hartke 4x10 combo, which i don't really like
 
$100 won't get you anywhere with speakers. Save up and get a decent cabinet. If you can find one that is 8 ohms, you can always get another one in the future.
 
If I am reading this whole thing right,..... you are loading your amp with one cab that is an 8 ohm load,... then adding another that is a 4 ohm load,....and your amp head is an output of 4 ohms,....... is this correct so far.???



if so,.... what you are doing by using both cabs at once, is adding the two together giving you an ohm load of 12 ohms,.... and since your amp has an output of 4 ohms, you are taking an awful chance of overheating your amp,....

the proper thing to do is to match the output of your amp,... that way when you want to use it for it's 300 watts, you will at least have that to work with,....

the problem is,... when you add more speakers,.... if you use other plugs on the back of your amp,.... you are adding ohms together for one output,.....


Try plugging the 4 ohm 15" as a piggy-back to the twin 10",.... by daisy-chaining the cabs, you are running them at a lower ohm load than doing it the other way,....


and as for the one 10" not working,..... double check the solder connection,.... and try taking a piece of zip cord, (common two lead wire),... and while a signal is being fed to the cab,... take the zip cord, and touch the contacts from the other speaker,.... if you get signal,.. it could be the connection, the soldering, or the wire,..... if no signal,.... it could be the voice coil,... but a speaker not working right from the factory sounds to me like a warrenty thing,... or at the very least,.. a replacement at no cost,....


I would keep trying to contact the place where you bought the cab.....


Steve
 
Thatupstateguy said:
If I am reading this whole thing right,..... you are loading your amp with one cab that is an 8 ohm load,... then adding another that is a 4 ohm load,....and your amp head is an output of 4 ohms,....... is this correct so far.???



if so,.... what you are doing by using both cabs at once, is adding the two together giving you an ohm load of 12 ohms,.... and since your amp has an output of 4 ohms, you are taking an awful chance of overheating your amp,....

the proper thing to do is to match the output of your amp,... that way when you want to use it for it's 300 watts, you will at least have that to work with,....

the problem is,... when you add more speakers,.... if you use other plugs on the back of your amp,.... you are adding ohms together for one output,.....


Try plugging the 4 ohm 15" as a piggy-back to the twin 10",.... by daisy-chaining the cabs, you are running them at a lower ohm load than doing it the other way,....


and as for the one 10" not working,..... double check the solder connection,.... and try taking a piece of zip cord, (common two lead wire),... and while a signal is being fed to the cab,... take the zip cord, and touch the contacts from the other speaker,.... if you get signal,.. it could be the connection, the soldering, or the wire,..... if no signal,.... it could be the voice coil,... but a speaker not working right from the factory sounds to me like a warrenty thing,... or at the very least,.. a replacement at no cost,....


I would keep trying to contact the place where you bought the cab.....


Steve
Click to expand...


Hmmmm, there's a bit of disinformation here.

1) When you add speakers to an amp, they nearly always (maybe always always) add them in parallel, not series, so connecting a 4 ohm cab with an 8 ohm cab is not a 12 ohm load, it's more like 3 (too early in the morning to do the math, but 3 ohms is close). A rule of thumb is that a combined load in parallel is ALWAYS lower in ohms than the lowest impedance single load.

2) It makes no diff whether you plug the second cab into the second output on the amp or the parallel connection on the first cab, it's the same connection and gives you about 3 ohms.

3) The risk to an amp is in having a load of less ohms than the spec, not more. Do not give a 3 ohm load to an amp which is spec'ed at 4 ohms.

4) If you do what was suggested and go poking around with a test wire while the amp is running BE VERY CAREFUL. If you touch the wrong connector and short out the load, it can damage your amp VERY QUICKLY.

5) An amp does not "output" ohms, it puts out current at a voltage; the impedance (ohms) is dictated by the load.
 
If you are looking for a quick and cheap stopgap measure, open the two speaker cab and cut the wires to the non-working speaker. Make sure that the cut ends cannot touch anything (tape them off). Now it is a 16 ohm cabinet (assuming that we are correct in that what you have is two 16 ohm speakers in parallel) Connect the single speaker 8 ohm cab. That will give you a 6 or 7 ohm load, well within the comfort range of the amp.

Now, the 8 ohm speaker will dissipate more of the amp's power than the 16 ohm speaker; it will get 2/3 of it and the 16 ohm speaker will get 1/3. For a 300 watt amp, that's 200 and 100 watts, assuming that the amp is running at max power. If the 8 ohm speaker is spec'ed at 150 watts, there is a potential prob, although the power limits on a speaker tend to be quoted conservatively. If you back off on the amp a bit from maxxed out, you will probably be OK.
 
My Bad, I was not sure exactly how he was hooking up the multiple cabs,..... and as for the wire,.. I did not explain it clear enough I guess,..... I was only suggesting that he take a lead from the speaker that was working, and jump it to the one that wasn't, determining if the solder connections, or wire were the problem....

and if he is still getting distorted, or weak signal where the output load is close to what it should be, then there is something else very wrong,......

My suggestion of going back to where you bought it still stands,..... I am not a rich guy, so if I spend my hard earned dollars on something, I wanna make damn sure it works correctly, and where I bought it from has much to do with that,.....


Sorry for any miss info... but the facts are that the cab, and the amp should match when it comes to OHMS,.... if it does not,... the result is less sound than the amp is capable of producing, and a risk of damage to either speaker, or amp.....especially if the OHMS are too far away from amp ratings....
 
Thatupstateguy said:
Sorry for any miss info... but the facts are that the cab, and the amp should match when it comes to OHMS,.... if it does not,... the result is less sound than the amp is capable of producing, and a risk of damage to either speaker, or amp.....especially if the OHMS are too far away from amp ratings....
Click to expand...


Mostly true, but the risk of damage to the amp is far greater in running an amp spec'ed at a certain load into one of fewer ohms than there is in running it into one of more ohms. Possible damage to the speakers is a matter of power handling capability rather than anything to do with impedance.

One possible source of confusion is the terminology; a load of fewer ohms is termed a greater load, and vice versa.
 
Thatupstateguy said:
My Bad, I was not sure exactly how he was hooking up the multiple cabs,..... and as for the wire,.. I did not explain it clear enough I guess,..... I was only suggesting that he take a lead from the speaker that was working, and jump it to the one that wasn't, determining if the solder connections, or wire were the problem....
Click to expand...

I understand that, but if he were to touch his test wire to the grounded terminal of the suspect speaker (a 50% probability if he doesn't know which is which), then he presents a shorted load to the amp. This could damage the amp very quickly, maybe instantaneously. This test should NOT be done with the amp running, but with a meter or test lamp.
 
Just 1 small correction.

A 16 ohm cabinet connected in parallel with a 4 ohm cabinet will give you 3.2 ohms. You will burn up the amp.

There is no way to add any more speakers to a 4 ohm cabinet in parallel, it will always lower the impedance. If you hook them up in series, you will be fine.

You can run solid state amps at any impedance above the minimum (in this case 4 ohms) without damaging the amp. No, it won't be any quieter given the same efficiency of the speakers.
 
Thats true, any untrained person should not poke around inside anything to do with an amp unless you are ready to either DIE, or damage equipment....


sorry again,.. not thinking today at all,.....



must be a senior day for me....


OBOY I get to have jello..!!!!!!!




:confused: :confused: :confused:




:eek:




:D
 
the store i bought it from's website doesn't work anymore and the company (steel sound) is gone. they were part of a parent company called madison that i tried contacting, but their e-mail came back saying it was undeliverable.
 
and i'm not going to poke around. you know how when you tap on a speaker it gives way a bit and makes a deep tone? this one is absolutely stiff.
 
Farview said:
You can run solid state amps at any impedance above the minimum (in this case 4 ohms) without damaging the amp. No, it won't be any quieter given the same efficiency of the speakers.
Click to expand...

What do you mean it won't make it any quieter? If you run a 4ohm speaker from that amp it, the amp will deliver up to 300w. If you run a 8ohm speaker, the amp will deliver up to 150w of power. :confused:
 
VSpaceBoy said:
What do you mean it won't make it any quieter? If you run a 4ohm speaker from that amp it, the amp will deliver up to 300w. If you run a 8ohm speaker, the amp will deliver up to 150w of power. :confused:
Click to expand...
Wattage is a goofy measurement, it doesn't mean what you think it does. It is a measure of heat dissipation

Watts= amps X volts X length

Length is the length of wire, or in our case, the voice coil. When that gets changed (which would change the impedance), the wattage changes. However, the amps and volts stay the same.

150 watts into an 8 ohm load is the same as 300 watts into a 4 ohm load.

If you mix speaker impedances in a single system, the ones with the lowest impedance will be louder that the ones with higher impedance because they will draw more of the available power. That doesn't mean that a matched system of 8 ohm speakers would be louder than a matched system of 16 ohm speakers. The difference in response is caused by the mismatch, not by any difference in output from the amp.

Of course, not all speakers are equally efficient. So simply hooking up an 8 ohm speaker next to a 4 ohm speaker to see which is louder isn't a valid test unless both the speakers have the same efficiency.
 
Last edited:
VSpaceBoy said:
What do you mean it won't make it any quieter? If you run a 4ohm speaker from that amp it, the amp will deliver up to 300w. If you run a 8ohm speaker, the amp will deliver up to 150w of power. :confused:
Click to expand...

Very true, but another factor is the efficiency of the speaker, i.e., howmuch volume does that speaker produce from the 150w or 300w it is dissipating?
 
At any rate,.. here is a link to what is now the 'NEW' Steel Sound company you bought the cab from.....


If you press the issue,... making sure you mention you are a member of at least one music website that has over 15,000 members who are watching this for the outcome, and will base any future decisions about quality control etc and purchases from them,.....on what happens,.......



it's worth a shot anyway......



http://stores.channeladvisor.com/musicsupplycenter
 
Farview said:
Wattage is a goofy measurement, it doesn't mean what you think it does. It is a measure of heat dissipation

Watts= amps X volts X length

Length is the length of wire, or in our case, the voice coil. When that gets changed (which would change the impedance), the wattage changes. However, the amps and volts stay the same.

150 watts into an 8 ohm load is the same as 300 watts into a 4 ohm load.

If you mix speaker impedances in a single system, the ones with the lowest impedance will be louder that the ones with higher impedance because they will draw more of the available power. That doesn't mean that a matched system of 8 ohm speakers would be louder than a matched system of 16 ohm speakers. The difference in response is caused by the mismatch, not by any difference in output from the amp.

Of course, not all speakers are equally efficient. So simply hooking up an 8 ohm speaker next to a 4 ohm speaker to see which is louder isn't a valid test unless both the speakers have the same efficiency.
Click to expand...

Hmm... so are you saying that a 100w amp into a 8ohm loud (rated) would be louder than 100w amp into a 4ohm load? ((assuming all else is equal))
 
Farview said:
Wattage is a goofy measurement, it doesn't mean what you think it does. It is a measure of heat dissipation

Watts= amps X volts X length

Length is the length of wire, or in our case, the voice coil. When that gets changed (which would change the impedance), the wattage changes. However, the amps and volts stay the same.
Click to expand...

??? I don't know where you got your equation for computing power, but here is the correct one:

P (watts) = VI (Volts X Amps) = V^2/R (Volts squared divided by resistance) = I^2 R (Amps squared X resistance).

Running a power amp into more load (less impedance) will be louder, all other things being equal. All other things are very seldom equal, though. ;^)
 
hey, i know i'm being confusing by i got my numbers wrong before. my 15" cab is 8ohms. is there any hope for this bass rig to work or should i just live with sounding bad for a few weeks and buy a better cab? i'd really like to go down to the music store today and grab a speaker for it but i don't want to screw anything up and waste even more money.

i e-mailed music supply center, i'll see what they say.
 
so to clarify again, this is what i'm dealing with at the moment:

4ohm amp head
2 16ohm 10"s
8ohm 15"

i like the 2x10 enclosure, its light and seems to be built pretty alright, so i don't mind replacing the speakers. i like my 15 too! i just don't want to do anything stupid.
 
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