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Matching ohms

Jul 4, 2016
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NJ
My Trace Elliot combo has 1x15 speaker at 300w and 8 ohms. I want to add another speaker cab. Do I need another 300w or below speaker and does it have to be 4 or 8 ohms? Any advice would be appreciated.
 
Also, you need a speaker rated greater than or equal to (not less than) the amp wattage at the given impedance. Adding an 8ohm speaker in parallel will get you 4 ohms, the head may well put out substantially more power at 4ohms than 8 (up to twice).
 
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Don't mean to derail, but I have a similar question. I have a Class D Traynor head SB500H and it has 2 speak connectors on the back, both are rated for 4ohms. So could I hook up 2 4 ohm, or 2 8 ohm cabs to this amp?
Two 8-ohm cabs. That amp is rated at 4 ohms, so two 8-ohm cabs will give you that. Two 4-ohm cabs would result in a 2-ohm load which would overtax your amp.
 
Two 8-ohm cabs. That amp is rated at 4 ohms, so two 8-ohm cabs will give you that. Two 4-ohm cabs would result in a 2-ohm load which would overtax your amp.
sb-500-back-V2.jpg


Ok it is making sense to me now. I thought it was 2 4 ohm channels, but it is just the one channel divided into outputs. Apparently the sales person misinformed me when I bought it. This makes me want to try and find another matching Epafini PS112 more than anything now. Because I am guessing that 2 of those should easily equal my 4 10 at 4ohms, then loose a lot extra weight.

Does that sound right? I have a hard time understanding this whole ohms thing. Back in the day I used a preamp going into a powered cab, and that was all I ever needed. Other than that its been mainly combos.Also out of the 36 years Ive been playing, most all of it except for the past 2 years have been home playing. So I never had the need to learn this stuff.
 
I was thinking that matching would be best idea. I just don't want to spend cash and blow it out. It would be easiest to get another TE cab, if I can get one a decent price.

Generally if a combo can take another cabinet it will be equipped with an Extension speaker socket as mentioned in post #3. If it does not have such a socket then it’s almost guaranteed that the amp is fully loaded by the internal driver(s).
 
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So, I can add one external but has to be 8 ohms and max 200w, because my amp head is 200. Or 300w because the one in the combo is 300w

you could run a 3 million watt rated cab not just one rated below 200 watts depending on the output power at 4 ohms, the watt rating on a speaker cab is the maximum power handling capacity of whatever cab you use not how much power it needs. You need to figure out how much power your amp puts out at 4 ohms, a SS amp will usually put out somewhere around 1.5 times what it does at 8, so you then take that, say it's 450 watts at 4 ohms and divide it by two as the cabs will split up the output power equally, so your cab should be somewhere around a minimum of 225 watts capacity. I would get a matching cab if the make them.
 
you could run a 3 million watt rated cab not just one rated below 200 watts depending on the output power at 4 ohms, the watt rating on a speaker cab is the maximum power handling capacity of whatever cab you use not how much power it needs. You need to figure out how much power your amp puts out at 4 ohms, a SS amp will usually put out somewhere around 1.5 times what it does at 8, so you then take that, say it's 450 watts at 4 ohms and divide it by two as the cabs will split up the output power equally, so your cab should be somewhere around a minimum of 225 watts capacity. I would get a matching cab if the make them.

That's what I was thinking, but also wanted to look into a 4x10 to add some top end. Luckily, there are many used T.E. 15 cabs out there.
 
Adding a 4x10 to your 1x15 trace combo will cause a mismatch in how hard the single 15" speaker will work compared to the each of the four 10" speakers. Best to get another trace 1x15 or perhaps they made a 2x10 that mates well with their 1x15 cabs and combos? One 15" speaker and two 10"s have a very similar total speaker area this making a mismatch less drastic and potentially less damaging to te overmatched speaker(s).
 
Adding a 4x10 to your 1x15 trace combo will cause a mismatch in how hard the single 15" speaker will work compared to the each of the four 10" speakers. Best to get another trace 1x15 or perhaps they made a 2x10 that mates well with their 1x15 cabs and combos? One 15" speaker and two 10"s have a very similar total speaker area this making a mismatch less drastic and potentially less damaging to te overmatched speaker(s).
Thanks for the advice.