Another question about ohms

[Maynjo]

Hey guys. I have an AG 700 head and love it. I want to get the SL410x cab to match. I was planning on getting the 4 ohm version as I probably will never need more than just the 410. Anyways, If by some chance I do end up needing more volume later, the AG 700 can go down to 2.6 ohms. My question is if I had 2 410 cabs, one being a 4 ohm and the other being and 8 ohm would it sound bad for any reason? Both cabs would be 410s but they'd be putting out different volumes. Which one would be better on top? And most importantly, any rumors of an sl 210 coming out eventually? Because that would be perfect.

 

[Raf Seibert]

Not so much sounding “bad”, as that the 4 ohm cab will be about twice as loud as the 8 ohm cab. That’s one of the reasons identical cabs are recommended.

Raf

 

[BassmanPaul]

Get the 8Ω 4x10 as the difference in volume between a 4Ω load and an 8Ω one will be barely noticeable.

 

[Maynjo]

Get the 8Ω 4x10 as the difference in volume between a 4Ω load and an 8Ω one will be barely noticeable.

I've read a lot on that subject, and it seems like most people agree with that assessment. But if that's true, then wouldn't it be fine to use a 4 ohm and an 8 ohm as they shouldn't be very far off volume wise? My situation is in my foreseeable future I don't think I'll ever need the second cab. so I'd really just like to have the 4 ohm just so I can use the head to it's fullest if I need to.

 

[BassmanPaul]

Why follow a route that will eventually lead you into possible problem areas. If you buy an 8Ω cabinet and then follow that up with a second 8Ω cabinet your power distribution will be even. If you are trying to wring every last watt out of your amp you are basically wasting your time.

As an example if you’d like to get your cabinet twice as loud you’d have to increase the power you are suppling that cabinet by a factor of 10.

 

[Jack]

Not so much sounding “bad”, as that the 4 ohm cab will be about twice as loud as the 8 ohm cab. That’s one of the reasons identical cabs are recommended.

Raf

Maybe 3dB louder as it's getting twice the power but twice the power is not twice as loud.

 

[Al Kraft]

I would favor the two 8 Ohm cab approach so I could get the most out of my "big rig" when I really needed that kind of firepower. A single SL410 and an AG700 (even at 8 Ohms) should be a pretty serious rig all on its own.

 

[Maynjo]

Thanks guys, good info.

 

[Maynjo]

Has anyone happened to try the TC RS210s? I could get 2 of those for less than the sl410x and then add a 3rd one if I need it.

 

[Old Garage-Bander]

Not so much sounding “bad”, as that the 4 ohm cab will be about twice as loud as the 8 ohm cab. That’s one of the reasons identical cabs are recommended.

Raf

Wouldn't the 4 Ohm cab get 2/3 of the power and the 8 Ohm cab get 1/3 of the power?
Then 2/3 is twice the power of 1/3, but twice the power isn't twice as loud, is it?
I thought you needed something like 10 times the power to be twice as loud?
Wouldn't the 4 Ohm just be barely noticeably louder at twice the power?
Isn't all of this due to the non-linear relationship between power and how our ears perceive loudness?

-edit- Didn't read all the post. I think my questions are answered. Thanks.

 

[Al Kraft]

Wouldn't the 4 Ohm cab get 2/3 of the power and the 8 Ohm cab get 1/3 of the power?
Then 2/3 is twice the power of 1/3, but twice the power isn't twice as loud, is it?
I thought you needed something like 10 times the power to be twice as loud?
Wouldn't the 4 Ohm just be barely noticeably louder at twice the power?
Isn't all of this due to the non-linear relationship between power and how our ears perceive loudness?

-edit- Didn't read all the post. I think my questions are answered. Thanks.

Twice the power will not get you twice as loud...and I agree on the difference between single 4 Ohm and 8 Ohm cabs not being enough in my mind to justify not going with two 8 Ohm cabs and getting the maximum capability in the two cab scenario when extra Watts are most effectively utilized.

The single cab 4 Ohm versus 8 Ohm question has a sub-optimized bias that limits maximum capability in the context of the bigger picture IMO. Not right or wrong, just a situation where you need to be clear on your requirements and the value/weight you place on greatest possible capability with one cab, versus having the maximum possible capability in situations where two 410 cabs are necessary to start with.

Sometimes requirement trade-offs are as frustrating as design trades. However, in this case we have design solutions and known capabilities to inform the requirements determination process and help us understand interrelationships and implications. And yeah, I did this kind of stuff for a living with military weapon systems.

 

[Raf Seibert]

You are right garage-bander. That’s why I said, “about”. I simply didn’t want to take time to explore all of the factors involved. I just wanted to give the OP a rough idea of the difference in output of the two cabs. That, and to assure him that there wouldn’t necessarily be a notable difference in tone.

 

[HolmeBass]

Well OP I think you could go either route. A +3dB difference is not “barely noticeable”. It is clearly noticeable, although not a big difference in perceived volume. The louder it is, the more apparent difference +3 dB will make. The JND - just noticeable difference - is quite sensibly just about 1 dB.

So you really can’t go wrong here. If you get a 4 ohm and an 8, put the 4 on top so you can hear if you start pushing it too hard.

I will say with either the 8 or 4 ohm cab that will be a very loud rig. And personally, I would get an 8 ohm cabinet. Then if you ever need to get stupid loud you can run three of them.

 

[Maynjo]

And personally, I would get an 8 ohm cabinet. Then if you ever need to get stupid loud you can run three of them.

Haha I like the way you think. Doubt I would ever need 3 cabs. Doubt I even ever need 2 cabs. That makes a lot of sense about the 4 ohm on top, hmm. I was originally planning on just going with the 4 as the whole idea of even getting that cab is to downsize my rig to something small, but usable for anything. But everyone seems to agree that it would hardly make any noticeable difference. I guess my main question without all the other nonsense is just, How bad would it sound to combine the 8 with the 4?

Edit: And also, would a 4 ohm/8 ohm actually be less loud than an 8ohm/8ohm? as the AG 700 is rated 700 watts @4ohm but also 700 watts at 2.6 ohms.

 

[Old Garage-Bander]

Well OP I think you could go either route. A +3dB difference is not “barely noticeable”. It is clearly noticeable, although not a big difference in perceived volume. The louder it is, the more apparent difference +3 dB will make. The JND - just noticeable difference - is quite sensibly just about 1 dB.

So you really can’t go wrong here. If you get a 4 ohm and an 8, put the 4 on top so you can hear if you start pushing it too hard.

I will say with either the 8 or 4 ohm cab that will be a very loud rig. And personally, I would get an 8 ohm cabinet. Then if you ever need to get stupid loud you can run three of them.

I wonder how perceptible the 3db difference is when playing along with another cab that is operating at 3 db more than the one being compared? In other words, just one cab 3db louder than itself is noticeable. But how noticeable is that difference when another cab is also in play at the same time?

 

[ashtray]

You could avoid all the confusion and get an 8 ohm 2x10 cab that would match perfectly with a 4 ohm 4x10.

 

[gumtown]

Get 3 x 210 8ohm cabs, then you can mix/match/stack them in many different ways.
stack 'em 6x1, 1x6, 2 vertical with 1 horizontal on top, vertical+horizontal+vertical.

 

[Maynjo]

I really was considering 3 2x10s, that's my ideal setup.

 

[HolmeBass]

I wonder how perceptible the 3db difference is when playing along with another cab that is operating at 3 db more than the one being compared? In other words, just one cab 3db louder than itself is noticeable. But how noticeable is that difference when another cab is also in play at the same time?

Good question. I have no personal experience there. And if both cabinets are nearly identical, except for impedance, it would be very difficult to tell the contributions of each cab to the overall sound.

I’ve read here on TB that going from one 8 ohm cab to two (identical) cabs is roughly +6 dB: a second identical radiator is twice the acoustic power, +3 dB; the amp puts out twice the wattage, another +3 dB.

Adding an identical 8 ohm to a 4 ohm does not add as much. The second radiator is only getting 1/2 the power, so it is not adding +3, but rather +1.5; the amps wattage jump would also add just 1.5. I think.

But OP noted the amp does not produce any additional wattage going from 4 ohms to 2.6 ohms. So you are actually going to run less power into the 4 ohm box when you add the 8 ohm one.

I think it would still get louder, but only a little bit. The same power through twice as many speakers should net +3 dB. The apparent volume could be helped a bit as you would have more speakers pointed at your head, closer to your head.

The three 8 ohm 210s seems like a better, more flexible solution. Ultimately not as loud as two 8 ohm 410s though unless you get some very efficient 210s. And these cabinets are not interchangeable. Some companies’ 210s are much better than others, same for 410 or any other alignment.

Two vertically stacked 210s is a real popular rig these days, helping ameliorate the beaming issue with the common square 410 cabinet and getting a speaker closer in line with your head, which really improves apparent volume, frequency response, and intelligibility.

 

[Maynjo]

Good question. I have no personal experience there. And if both cabinets are nearly identical, except for impedance, it would be very difficult to tell the contributions of each cab to the overall sound.

I’ve read here on TB that going from one 8 ohm cab to two (identical) cabs is roughly +6 dB: a second identical radiator is twice the acoustic power, +3 dB; the amp puts out twice the wattage, another +3 dB.

Adding an identical 8 ohm to a 4 ohm does not add as much. The second radiator is only getting 1/2 the power, so it is not adding +3, but rather +1.5; the amps wattage jump would also add just 1.5. I think.

But OP noted the amp does not produce any additional wattage going from 4 ohms to 2.6 ohms. So you are actually going to run less power into the 4 ohm box when you add the 8 ohm one.

I think it would still get louder, but only a little bit. The same power through twice as many speakers should net +3 dB. The apparent volume could be helped a bit as you would have more speakers pointed at your head, closer to your head.

The three 8 ohm 210s seems like a better, more flexible solution. Ultimately not as loud as two 8 ohm 410s though unless you get some very efficient 210s. And these cabinets are not interchangeable. Some companies’ 210s are much better than others, same for 410 or any other alignment.

Two vertically stacked 210s is a real popular rig these days, helping ameliorate the beaming issue with the common square 410 cabinet and getting a speaker closer in line with your head, which really improves apparent volume, frequency response, and intelligibility.

Probably the most helpful response I've gotten, thanks.