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Ohms FAQ

#721
KJung said:
You are a bit confused here:) Cone diameter is one of the least important features of a driver when discussing power handling, low end extension, etc. Yes, all other things being equal (which they never are), a 15" driver will have higher sensitivity than an otherwise identically spec'd 10" driver (I think anyway), but that is a separate issue.
Click to expand...

ok,

Three speakers with 8 Ohm ....
Which speaker will be overpowered?

Different question,

Two cabs:
1) 210, 4 Ohm
2) 115, 8 Ohm

How much of the power is derived to each cab?
How much of the power is derived to each speaker?

Next questions:

Which cab plays louder?
Which speaker plays louder?
 
#722
acmebass said:
Nope. I was referring to two 2x10 cabs. That's four drivers, not two.

An 8 ohm 2x10 does not have 8 ohm drivers in it. It can be done with two 4 ohm drivers, or two 16 ohm drivers, but it's impossible to wire two eight ohm drivers in such a way as to get a resulting impedance of eight ohms.

I wish you were right...

The rest of your post is extremely generalized, and makes no sense to me.

Thanks,
Andy
Click to expand...

Sorry, I was very wrong (totally confused). I mismatched in my mind speaker sizes 10s and 15s and therefore all the things I wrote in that post is indeed rubbish.

Thanks
Klaus
 
#723
ThisBass said:
If you compare apples to beans you are right.
But if you compare apples to apples you are wrong.

If I'd try to compare home theater speakers to PA speakers I would do a very bad mistake.

If I'd compare similar designed speakers so I don't feel I would do something wrong because I'm trying to compare apples to apples.

It's very often figured that a 210 is better at the lows then a 15. And even a 210 plays louder then a 15.
Refering to different speaker designs this argument may be true, but that is not a valid point that should be discussed.

There are a very lot of different speakers availible at the market with very different specs for very different design goals and tastes and applications at very different sale prices.

So comparing apples to apples is not as easy as it very often looks like!

Nearly every high performance 15 speaker knocks off a 210 of same speaker series if the cab is well designed.
Click to expand...

It is not possible to compare apples to apples between a 15" and a 10" speaker period. You have different piston areas. You generalized and that is what I disagree with.
A high performance 210 will out perform a poorly designed single 15" and a high performance 15" will out perform a poorly designed 210. In my opinion your statement was completely off base and would lead to non educated player's confusion. Which your response seems to agree with?

I have a high performance 12" theater sub that will out perform my 2 15" PA bins, but it is not sturdy enough for me to risk on gigs. THAT is a different application and not relevant for comparison.
 
#724
acmebass said:
Power into each cab will be equal to V2​/Z,

Where V = voltage, and
Z = impedance

Therefore, the 4 ohm cab will receive twice the power of the 8 ohm cab.

Consequently, connecting a 4 ohm 2x10 in parallel with an 8 ohm 2x10 will be "incorrect," because the woofers in the 4 ohm cab will each receive twice the power of the woofers in the 8 ohm cab.

Connecting a 4 ohm 4x10 cab in parallel with an 8 ohm 2x10 will be correct, because the power will be distributed evenly between the 6 woofers.

The resulting load will be 2.67 ohms.
Click to expand...

+1
That is absolutely correct.
Your post relates to post #12.
Sorry that I did not read with sufficient care in this context.
I feel intense shame!
 
#725
B-string said:
That is the myth not actual fact.
A 210 can be deeper and have less midrange than a 115. It all depends on the individual speakers and the box built for them. Size of the driver means very little until you start mixing driver sizes without being crossed over. If you stack them in vertical alignment they should play well with each other, but looks odd on stage. Matching cabs works much better, twice as much of what you like and controllable.

Not a silly question ;)
Click to expand...

I have no words.

10s are better then 12s and 12s are better then 15s and 15s are probably better then anything else bigger then 15s

So it would be best to use some 8" in a well designed cab because the 8s are better then 10s are better then ....
How about 6" ?


In general 10s have more top end frequency range then 15s
In general a sound feels a bit middy if the freq.-band above 2.5kHz is missing.
It sounds like there is more mids, but it is not in total.
 
#728
Thats right.
But very often the reading on TB implies that smaller speaker diameters are better then the bigger ones.
If someone calls for 15s then the TB recommendation yields to 10s.
I'm wondering a little bit why the 12s are underexposed at TB every time if anybody calls for 15s at the forum?

I like my 212+8 very much but would never argue it is the answer to everything.
The cab is fitted with carefully selected premium speakers. Those speakers have many advantages but also some disadvantages that I don't like to tell about just this moment because it is off topic too much.

Take a low/medium budget average 15 cab off the rag, spend a few bugs more for a 210 cab and don't make wondering yourself why the 210 cab performs better to your taste and ears then the average 15 that is affordable to everyone's payoff.

I agree very much to a very considered member of TB:
The building and designing of cabs is a kind of art.
 
#729
ThisBass said:
Thats right.
But very often the reading on TB implies that smaller speaker diameters are better then the bigger ones.
If someone calls for 15s then the TB recommendation yields to 10s.
I'm wondering a little bit why the 12s are underexposed at TB every time if anybody calls for 15s at the forum?

I like my 212+8 very much but would never argue it is the answer to everything.
The cab is fitted with carefully selected premium speakers. Those speakers have many advantages but also some disadvantages that I don't like to tell about just this moment because it is off topic too much.

Take a low/medium budget average 15 cab off the rag, spend a few bugs more for a 210 cab and don't make wondering yourself why the 210 cab performs better to your taste and ears then the average 15 that is affordable to everyone's payoff.
Click to expand...

Not sure where you are reading that 'smaller speaker sizes are better than large ones'. Yes, regarding upper midrange dispersion, there is a bit of an advantage to a smaller cone, but other than that, again, driver size really isn't that key to finding a cab that fits your tone goals.

As many have stated above, there are 'tight and bright' 15 cabs, there are subwoofer voiced 10 loaded cabs, and vice versa and everything in between. Same with 12's and even 8's.

Better to not focus very much on driver size when making a cab choice, but rather the tonality you want, the volume you need, and the size/weight you are willing to deal with. When you combine those key issues, you might have a nice range or 10 loaded, 12 loaded and 15 loaded cabs to choose from that all sound reasonably similar (at least similar enough to make a give player happy).
 
#730
KJung said:
Not sure where you are reading that 'smaller speaker sizes are better than large ones'.
Click to expand...

The TB generalisation 210 vers. 115

KJung said:
Yes, regarding upper midrange dispersion, there is a bit of an advantage to a smaller cone, but other than that, again, driver size really isn't that key to finding a cab that fits your tone goals.
Click to expand...

That's right. Essential for bass tone goals is the 2nd Harmonic.
That is appro 80hz for E1 and appro 60Hz for B0.
80Hz of flat response do most of all cabs, 60Hz flat do not all but some do it well.
Sometimes cabs are tuned with a significant hump around 70..120Hz.
Thats even possible for 210s cabs.
Whereas a 15 cab that goes deeper but without a hump sounds more flattened at the lows on B0 and E1.

So it's not a question of diameter but a question of different ....

KJung said:
As many have stated above, there are 'tight and bright' 15 cabs, there are subwoofer voiced 10 loaded cabs, and vice versa and everything in between. Same with 12's and even 8's.
Click to expand...

Some 15s are bright but some 15s don't, some 12s are bright but some 12s don't, some 12s are bright but some 10s don't,

Some 10s go deep but some others don't, some 12s go deep but some others don't ...

Some 10s have very good efficiency but some others are like a lame dug. Some 12s have medium efficiency whereas some others let explode the stage by the same input power (at the same Ohm nominal rating).

But this "listing" means genaralisatiion at its best.
It is not possible to make a choice that fits all the tastes of everyone.
If you give accent to one of a sound influencing parameters you accept a disadvantage at least of one at others.


KJung said:
Better to not focus very much on driver size when making a cab choice, but rather the tonality you want, the volume you need, and the size/weight you are willing to deal with. When you combine those key issues, you might have a nice range or 10 loaded, 12 loaded and 15 loaded cabs to choose from that all sound reasonably similar (at least similar enough to make a give player happy).
Click to expand...
:bassist:
 
#732
ThisBass said:
That's right. Essential for bass tone goals is the 2nd Harmonic.
That is appro 80hz for E1 and appro 60Hz for B0.
80Hz of flat response do most of all cabs, 60Hz flat do not all but some do it well.
Sometimes cabs are tuned with a significant hump around 70..120Hz.
Thats even possible for 210s cabs.
Whereas a 15 cab that goes deeper but without a hump sounds more flattened at the lows on B0 and E1.
Click to expand...

Just to be clear, this is not what I'm talking about. A speaker of any diameter can be designed and tuned to sound pretty similar down low.

Cone size impacts the beaming of the top end of the frequency range. The larger the cone, the more frequencies in the upper midrange/treble area tend to beam a bit. That isn't really a huge deal with bass guitar backline, but is a difference by driver diameter.

On the low end, you can get pretty much wherever you need to go with any driver size. Of course, to get VOLUME of that tone, you might need more smaller drivers versus less larger drivers.
 
#734
KJung said:
Just to be clear, this is not what I'm talking about. A speaker of any diameter can be designed and tuned to sound pretty similar down low.

Cone size impacts the beaming of the top end of the frequency range. The larger the cone, the more frequencies in the upper midrange/treble area tend to beam a bit. That isn't really a huge deal with bass guitar backline, but is a difference by driver diameter.

On the low end, you can get pretty much wherever you need to go with any driver size. Of course, to get VOLUME of that tone, you might need more smaller drivers versus less larger drivers.
Click to expand...

fs, VAS, Qts, Vb, fb,

fs and Qts remain constant never the less how many speakers, VAS and Vb and fb are dependent on total number of speakers and cab net dimension and port tuning.

Comparing speakers of same series means at least fs is different.


As I told above there is no black or white rather lots of gray shades if speakers are compared.
But you can't decrease fs by doubling the total number of speakers in a cab.
 
#740
dmusic148 said:
16+8=24. Divide by the number of loads (2) =12.
Other configurations are more complex to figure.
Click to expand...

Nope, rethink that for a minute. Parallel configs always yield a number lower than the smallest single resistance. The link I posted shows the correct formula, R1 X R2/(R1+R2) = 5.33 ohms. I'm lazy and just use the calculator though...;)
 

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