Changing drivers - is it worth it?

[Graham56]

Ive posted on another thread how I need to fix some of the joints on my cab, but while Im on it, is there much to be gained by changing the drivers?

 

Its an Ashdown MAG 210. The speakers are Ashdown Blue Line 10, each rated at 100w at 16 ohms to give an 8 ohm cab.

 

I drive them from an Ashdown MAG head which gives 150w at 8 ohm and 300w at 4 ohm.

 

I struggle to keep with the band volume and find I have to run the head at very near full throttle, usually at least 3/4 on the output knob.

 

One option is to add another 8 ohm cab but that would give me space problems with transportation and weight problems for my back! Another is to buy a much lighter and more powerful cab but that will have to wait until my income is a bit more reliable.

 

Celestion do a reasonably-priced 10 driver rated at 200w at (correction) 8 ohms. I'm told they also sound pretty good. If I were to drop two of these into the cab Id end up with a single 210 unit rated at 4 ohm.

 

Would I notice the difference? Would there be much more volume? Would the the fact that the Celestions are rated at 200w and the amp claims to be 300w be an issue?

 

Of course, if the vibration from the existing speakers is causing problems with the cab structure may be I shouldnt be considering this....!

 

Cheers

 

Graham

[The Geoff]

You'd end up with a single 210 unit rated at 2 Ohms - not 4 - you'd need 2 x 8 Ohm speakers in parallel for 4 Ohms.

 

You could wire 2 x 4 Ohms in series for 8 Ohms, but that would gain you nothing.

 

Also, different speakers may not work well in the cab.

 

G.

[Graham56]

Sorry Geoff, I wrote the wrong impedance for the Celestions. They are 8 ohm, which would give me a 4 ohm cabinet.

 

The cabinet is a simple chipboard box with a full-width slot at the front, under the face with the two drivers in it. There is no shaping inside. Would different drivers react differently with the box?

 

Cheers

 

Graham

[jcadmus]

Don't know much about that cab, but generally speaking it probably uses the speakers it's designed for -- throw in something else, and you don't know what you'll get. May sound better, may not.

 

It all has do with things like Thiele-Small parameters and a bunch of other engineering stuff I don't really understand.

[yourlord]

Unless the celestions are a lot more efficient than the ashdowns, you would notice an increase in volume, but not a lot. The general rule of thumb is it takes 4 times the power to be twice as loud..

 

If you want your 100W rig to be twice as loud, you would need 400W. If you want your 400W rig to be twice as loud you would need 1600W. Diminishing returns..

 

Efficiency plays into the equation so if you have a speaker that is really inefficient, and compare it with one that is really efficient, the more efficient speaker will sound louder with all other things being equal.

 

What all that extra power gains you is headroom. So you don't have to run the amp at full power and use that spare juice for smacking the front row in the face with your awesome accents/slaps/pops/etc..

[alexclaber]

Although switching to a 4 ohm nominal load will get some more power out of your amp you'll probably run into the usual and oft forgetten problem that the excursion limited power handling of those Celestions is likely to be far lower than their 200W thermal power handling rating. I can't see any driver switch giving you much benefit.

 

The best low budget solution is to get the band to turn down a bit (point the guitar amps at the guitarists' ears), slightly reduce the lows and boost the mids on your EQ, turn the cab on its side so you can hear it better and maybe tilt it upwards a bit and try to always position yourself on stage so your cab is backed up against a wall or (even better) in a corner. Do all that and you will be amazed by the results!

 

When funds allow if you want a louder lighter cab then you know where to come!

 

Alex

[The Geoff]

As noted above, cabs are usually designed with a particular make/model of driver in mind. Chucking in a different item is a lottery. If the Theile-Small parameters are very similar then it might be ok - if they are markedly different, it's probably not going to improve things tonally.

 

What going from 8 Ohms to 4 Ohms *will* do for you is change the rating from 150to 300W - you already know this. The result of this is to push up the point at which the output starts to break up & approach clipping, thus giving you a cleaner signal at the same previous volume, or pushing to a slightly warmer signal with a small increase in volume.

 

To be fair, the best way to sample this would be to borrow another 8 Ohm cab & give it a try - it won't be the same as substituting your 2 x 10 drivers, but it'll give you some idea of the signal you can expect.

 

All things remaining equal, adding another speaker adds a perception of increased volume anyway. I remember Alex Claber discussing this somewhere - he's one of the guys who really understand all this stuff. You could PM him - you'll also find him on Talkbass.

 

If it were me, I'd seriously consider adding another cab, rather than swapping drivers.

 

Personally I use a 1 x 12 and a 1 x 15. Hopefully, if we get a few gigs in the New Year, I'll get a 4 x 10 to sit on top of the 15.

 

ADDED>>>>>>>>>

 

I see Alex has already answered - I've spent so long getting the words right on this, that he beat me to it!!!!!!!

 

G.

 

[moot]

I would add that dropping in new drivers without considering what space they are designed for could bring the opposite of what you are trying to do here.

 

My rule of thumb has always been have a rig that can drown out the drummer.

 

Ask Santa for a new rig.

 

*edit* Damn! Goeff beat me to it!

[davio]

The cab is $230 new on MusiciansFriend. Wouldn't a pair of Celestions be approaching the cost of the cab? I would think it would be worth it to wait until you have just a little more money and spend it on a better cab. Then you can sell the MAG and have a little pocket money.

[alexclaber]

What going from 8 Ohms to 4 Ohms *will* do for you is change the rating from 150to 300W - you already know this. The result of this is to push up the point at which the output starts to break up & approach clipping, thus giving you a cleaner signal at the same previous volume, or pushing to a slightly warmer signal with a small increase in volume.

 

To be fair, the best way to sample this would be to borrow another 8 Ohm cab & give it a try - it won't be the same as substituting your 2 x 10 drivers, but it'll give you some idea of the signal you can expect.

 

Two 8 ohm cabs with 300W shared between them will be quite a lot louder than one 4 ohm cab with 300W into it (assuming speakers identical bar nominal impedance). There are two reasons for this - the first is that the sensitivity of four 10"s is 3dB higher than that of two 10"s (greater radiating area increases efficiency of power transfer into the air). The second is that the power handling of four 10"s will be twice as much (i.e. 3dB greater) than that of two 10"s. This may not seem significant but it is because of the unquoted excursion limited power handling being much lower than the quoted thermal power handling.

 

If you try a pair of 8 ohm 2x10"s and then get a 4 ohm 2x10" expecting a similar sound and max SPL then prepare yourself for serious disappointment!

 

Alex

[Griffinator]

 

There's just no substitute for mass moving air.

[TimR]

... the unquoted excursion limited power handling being much lower than the quoted thermal power handling.

...

Alex

 

erm? yes ok mate..

 

What Alex is saying is that the amount that the speakers move in and out (excursion) is not usually known, but it has a greater affect on the sound volume than the power rating. Which is how much electricity the cabs can take before they catch fire.

 

I think

 

The cabinet volume is one of the main concerns. You could just chuck your dimensions into WinISD Online to see what sort of frequency plot you would get. That is; if you can get the Theile-Small parameters for the Celestions. Even if you can get the cab to go louder it might not sound pretty.

 

You should then be able to calculate the acoustic power output using those values.

 

Worst case scenario, get the speakers and try it. If it doesn't work as you expect, sell the speakers or whole cab on ebay to mitigate your losses.

[TimR]

Or if all that is too complicated, What drivers are you looking at and what is the cabinet size? I'm sure someone with nothing better to do would calculate it all for you a lot quicker than working it out yourself

[alexclaber]

What Alex is saying is that the amount that the speakers move in and out (excursion) is not usually known, but it has a greater affect on the sound volume than the power rating. Which is how much electricity the cabs can take before they catch fire.

 

 

The amount that the speakers can move in and out without distortion is specified when a manufacturer is choosing drivers for their cabs - it's the figure labelled Xmax. The power it takes to reach Xmax varies with frequency and depends on the cabinet design and any manufacturer that knows what they're doing should have worked this out. However none of them like to tell you what this power level is because it's too embarrassing! Seriously, even a top-notch modern neo 4x10" that's rated at 1200W can't cleanly handle more than about 300W in the lows.

 

Celestion are unfortunately rather reticent in providing T/S specs so I wouldn't use their speakers as it's just trial and error to get an alignment that works well.

 

The Eminence DeltaLite II 2510 is about as good as current bass guitar 10" drivers get - here's Eminence's suggested cab sheet, which has plots of sensitivity, excursion and so on. May be enlightening!

 

http://www.eminence.com/pdf/cab-deltaliteII2510.pdf

 

Alex

[Tom Capasso]

You have a cab that shook apart and isn't loud enough? While I agree with others about getting the band to play lower, it sounds like you have an equipment issue.

 

I would glue it up as best you can and sell it. The return won't be enough for what you need, but it will be a start. If you change the drivers, you won't be able to sell it because folks will think you abused the cab and burned the speakers.

 

Tom

[Graham56]

Thanks to everyone for the useful and thoughful replies. It sounds as if changing the drivers will be a bit of a lottery and unlikely to help as much as I imagined.

 

I think I'll do what I can to fix the cab and strengthen the offending joint but leave the drivers as they are. Then put together the cash for another cab or a lighter, more powerful one.

 

In the meantime, getting the guitarist to point his amp at his own head might also help...

 

Thanks guys,

 

Graham

 

[alexclaber]

In the meantime, getting the guitarist to point his amp at his own head might also help...

 

Suddenly he'll discover that his volume knob turns anti-clockwise as well!

 

Alex

[Tom Capasso]

In the meantime, getting the guitarist to point his amp at his own head might also help...

I think you misunderstood. He should put the amp on top of his head. It will help him feel the full "weight" of his playing (as well as teaching him that anti-clockwise thing).

 

Tom

(:grin:I said "anti-clockwise" instead of "counter-clockwise":grin:)

[cec]

you have a 300 watt amp at 4 ohms adding an extension cab like a 1 15 at 8 ohms then your amp would use its full power 300 watts at 4 ohms (the ashdown is 500 watts peak)

without the extra cab your amp is using about half its output

i have a ASHDOWN C410t combo and with the 15 cab added it has more then enough power

[b5pilot]

All good advice. I'd say if you immediately want to increase volume get a second 8ohm cab. You'll be pushing more air so you will have more presence. A cab that handles more power isn't going to give you any more volume than the amp will allow. It's either that or get a new rig, Amp and cab, or get everybody to turn down and let the PA do the work unless your Pa is sub par. Unless you blew out the speakers in the cab I wouldn't mess with them.

Really, you shook your cab apart? You can try to reglue it but I don't know how good it will hold up unless you take it apart then reglue it. Maybe add some screws to strengthen it. Sounds like the joints in that cab weren't to well constructed. Unless you really like this cab I'd patch it then off it.