#1
I've got a Laney R410 bass cab which I'm running my Ashdown ABM 500 into.

Spec:
Power RMS 250 Watts
Inputs 2x Jacks
Impedance 8 Ohms
Drivers 4x10" Custom Celestion & Switchable HF Horn
Ports Triple Rear Ported
Frequency Response 50Hz - 4KHz
Sensitivity 98 dB/W@1M
Dimensions Width 579 x Height 579 x Depth 403

Is there a way that I can buy new speakers etc and re wire it so that I can make it into a 4 ohm 600 watt cab, that way I can use just the one cab to get the full 575 watts from my head.
'97 Modulus Flea Bass w/ Lane Poor
Warwick Corvette Bubinga


Gallien Krueger 700RB-II
GK 210 RBH
EB Volume Pedal, EHX Black Finger, EHX POG, Malekko B:Assmaster Germanium, EHX Holy Grail, KORG Pitch Black
www.myspace.com/astheends
#2
Yeah man just get 4 of these.

http://www.usspeaker.com/legend%20bp102-1.htm

800watt power rating.

Can also be wired 4-8 ohms.

It also picks up lower frequencies than the speaker you have now which is nice for bass
Guitars:
Ibanez UV777P
Ibanez RGD2127FX
Ibanez RG3120TW
Ibanez RGD7321
Ibanez RG6003FM
Ibanez SA160
Jackson Slatxmg3-7
Amps:
Baron Custom Amps K88
Rivera Knucklehead TRE
Fryette Sig: X
Randall RM4 /w Modded modules
Cabs:
Mesa 4x12
Bogner 4x12
Peavey 4x12(K85s)
Last edited by kylendm at Oct 20, 2009,
#3
Quote by kylendm
Yeah man just get 4 of these.

http://www.usspeaker.com/legend%20bp102-1.htm

800watt power rating.

Can also be wired 4-8 ohms.

It also picks up lower frequencies than the speaker you have now which is nice for bass
Absolutely do not do this ^
Sensitivity (1W/1m) SPL 92dB


You're giving up 6dB to gain the added power handling.
That means you would have to put 4 times as much power into the new speakers to create the same amount of sound.


Nowhere in there, did I bother to look at the Thiele-small parameters for those speakers and attempt to determine how well (or poorly) your enclosure would suit them. For this choice, it isn't worth the bother. Be sure to choose speakers that are of the same or greater efficiency/sensitivity.
Meadows
Quote by Jackal58
I release my inner liberal every morning when I take a shit.
Quote by SK8RDUDE411
I wont be like those jerks who dedicate their beliefs to logic and reaosn.
#4
Actually you get an extra 3dB each time you double the cone area so you would retain the same efficiency with this swap though at 92dB/W they are very low efficiency drive units and you can do much better.

SYK is spot on with looking at Thiele/Small though. Not all speakers will work in your cab. If it is sealed they may be OK but with a ported cab they will be poor without retuning.

In the UK Fane and Celestion offer better performance than these at the price.

If you are going to pay out for four new speakers why not simply build an extra cab to get the extra power? Changing the impedance to 4ohms will give you an extra 3dB, it will only be a little louder, doubling the watts doesn't mean doubling the sound. Adding an extra cab gives you 3dB from the extra watts and another 3dB from the increased cone area and you can leave the extra cab at home when you don't need the extra 6dB.

I usually avoid anything other than 8ohm drive units. most manufacturers design their speakers as 8 ohm units then make 4 and 16ohm speakers as an afterthought by just changing the voice coil which compromises the performance.

The 300W into your 98dB speakers will generate 122 dB at 1m. Isn't this loud enough especially with the EVO's compression? I operate an Ashdown into an 8 ohm speaker and I only ever get near maximum if I want to get shouted at by the rest of the band. You aren't wasting the extra watts they are just there in case you want to upgrade.

If you have enough volume and you are happy with the sound then leave well enough alone is the best advice. If you want to pursue this as a project get back to me and I'll give you some technical details.

Cheers
#5
Quote by Phil Starr
Actually you get an extra 3dB each time you double the cone area
True if the cones are all receiving the same power. But when you connect 4 speakers together, each gets 1/4 of the power. It's nearly a wash.
Meadows
Quote by Jackal58
I release my inner liberal every morning when I take a shit.
Quote by SK8RDUDE411
I wont be like those jerks who dedicate their beliefs to logic and reaosn.
#6
Quote by SomeoneYouKnew
True if the cones are all receiving the same power. But when you connect 4 speakers together, each gets 1/4 of the power. It's nearly a wash.



This is not what any of the textbooks say, have a look in Martin Colloms book High performance Loudspeakers for example. I haven't seen a mathematical proof of this but the effect seems to be due to the beaming effect as the sound radiates as a cone rather than as a sphere (a cylinder if the speakers are arranged in a line) and the effect is on axis mainly. There will also be an effect because of the improved coupling from the high acoustic impedance of the speaker and the low impedance of the air. What I can say however is that I also doubted the texts as you seem to be getting something for nothing so I checked it with a sound level meter and at 1m you do get 6dB.

Sorry to be such a nerd
#7
I want to build my own cab as a project at some point I don't know when atm though because someone used my head at a gig and somehow managed to blow it. I've gotta pay to repair it!

The reason I want the ne 4 ohm cab is so that i dont have to have to big cabs to get the full power from my amp, like i need at some gigs. I want to be able to have a half stack but have the power of a full stack.

I'm also considering at some point trying to build a cab with one 15' speaker, two 10' speakers and a horn, probably using celestions.

Any help or advice on this would be greatly appreciated.

Thanks
'97 Modulus Flea Bass w/ Lane Poor
Warwick Corvette Bubinga


Gallien Krueger 700RB-II
GK 210 RBH
EB Volume Pedal, EHX Black Finger, EHX POG, Malekko B:Assmaster Germanium, EHX Holy Grail, KORG Pitch Black
www.myspace.com/astheends
#8
OK you've got the two cabs but you want more volume so you only need to heft one around and you are keen to do a build. If you want help nearer the time then give me a pm.