Replacement Speakers. The old chestnut that never quite goes away..

[VTypeV4]

Very recently, I picked up an exceptionally cheap Ashdown 2x10 cab. It works perfectly and sounds really very nice but I want to use it with all my amps so it needs to be 4 ohms not eight. The V4 will operate happily at eight but the Ampegs, Beavis and the V6 need two or four..

 

I've looked at various drivers and a while back, remember modelling some Celestion Pulse (not the XL) in the very similarly sized Trace Elliot 2x10 cab with seemingly favourable results. Frustratingly, my Eminence cab modelling software doesn't like this computer.

 

The cab itself is just over 100 litres and tuned to around 50Hz. Tonally, I'm after non-rising-rate mids so a smooth, flat-ish response and the Celestions seem to fit the bill quite well.

 

Has anyone done similar or used different drivers and found great results?

 

 

[Bill Fitzmaurice]

With regard to modeling software it only predicts response within the region of pure pistonic response, which is roughly to two octaves above the driver Fs. To see what happens above that use the SPL chart on the driver data sheet, which is not influenced by the cabinet. I can't comment on the Eminence software, as I've never used it. For direct radiating speakers I use WinISD 0.7. 

[nikon F]

genuine question ( from someone relatively new to amps cabs etc ) why do the last three amps mentioned  " need " 2/4 ohms ? that aside,,what is the impedence of the speakers in the cab ?  if they're 4ohms  why not just rewire them in parallel ? 

[Downunderwonder]

44 minutes ago, nikon F said:

genuine question ( from someone relatively new to amps cabs etc ) why do the last three amps mentioned  " need " 2/4 ohms? 

Old school tube amps. They often neglected to provide an 8 ohm tap for the power transformer in favour of a 2 ohm one. Legacy of wanting to power the gig off the stage with twin 810 cabs.

[Lozz196]

Might be worth a call/message to Dave Green at Ashdown, see if he can recommend something.

[stevie]

100 litres is a bit on the large side, but the Celestion Pulse tens will work OK in that volume. They also have non-rising mids. Asking Ashdown, as @Lozz196 suggests, isn't a bad idea, as they sell replacement drivers at reasonable prices. 

[nikon F]

9 hours ago, Downunderwonder said:

Old school tube amps. They often neglected to provide an 8 ohm tap for the power transformer in favour of a 2 ohm one. Legacy of wanting to power the gig off the stage with twin 810 cabs.

thank you

[VTypeV4]

Thanks for the replies so far, folks.. 👍

[Phil Starr]

I'm happy to model the Celestion Pulse drivers for you or indeed look at any others. As @stevie has pointed out the cab is a little large for those drivers (we used a 30litre cab for the Pulse design we did during lockdown), but they look like they would work in a range of cabs.

 

It'll be good to return some of the help you've given me over the years

[Stub Mandrel]

Have you tried WinISD as mentioned above?

 

It's a bit non-intuitive if you don't know all the terms but I've managed to get it to work, so if you've used other cab software you should find it easy enough.

[Phil Starr]

I've done a quick look over my morning tea. I'll stick the results up below but before I do can I ask what you want to get out of this? 

 

If it is just a cab that is an Ashdown and sounds like an Ashdown then contacting @Ashdown Engineering is probably the way to go. They'll probably provide you with a couple of 8ohm drivers at a reasonable price, the cab will retain it's value and it's sound.

 

@Stub Mandrel's suggestion is a good one and I'm happy to help you set up WinISD if you get stuck. It's free and it works

 

If you want to go ahead with a mod then it's a question of what you want to get out of the mod and how much surgery/woodwork you want to do on the cab. If it has a tweeter you might want to look at the crossover too so it could be slightly more complex than just re-tuning the cab.

 

So this is the initial look at a pair of Celestion Pulse 10's in a 100l cab tuned to 50hz. For comparison there are two other more 'normal' responses in smaller cabs. That's partly to illustrate what we are all saying about the cab being 'a bit big' for the Pulses. Interestingly for a nerd like myself the response in your cab will be almost exactly that of an Extended 3db Bass Shelf/EBS-3 response which is a 'thing'. You just need to know this is the result. The bass shelf works well for bass guitar as the lower frequencies get reinforced by any hard surfaces near the cab but you just need to know that this will happen when you swap the speakers.

 

Green your cab with the Pulses 100l tuned to 50Hz

Blue is maximally flat SBB4 resonse in a 65l cab

Red is a more typical commercial cab response in a 45l cab 

 

 

 

Edited 3 hours ago by Phil Starr