Ashdown Mini 408 400watt

[gpw5150]

Hi All,

So, I bought an Ashdown 408 4x 8 mini.  It billed as being loaded with Sica neo drivers, but on inspection is loaded with Celestion tf0818's, I am not too bothere tbh.  However, I am getting very little definition of my low E and if I drop to D it gets a bit flappy.  I am no expert, but I have 2 lines of thought;

1, Driver frequency handling  - the Thiele small parameters set the TF0818 as more of a mid driver with low excursion (XMAX) and frequencey range from 70Hz.  I.e. the driver is not handling the bass well.

2, Lack of porting the cabinet - it is completely sealed - i.e. the cab is not allowing the drivers to handle the bass

I am happy with the cab size, weight and the mids are great, but the bass is a big flabby.  I have an option on some SWR  Celestion BG8-60 drivers or Faitalpro 8fe200 - The faital looks to be more of a bass driver.  Or I can drill a bloody great hole in the front of the cab and port it with a tube. 

 

Thoughts and advice please.

[stewblack]

I would hesitate to take a hole cutter to it without absolute reassurance from those here who know all about such things. 

If it doesn't suit your purpose maybe sell it on and put the money to something else. Once you take tools to it the second hand value must surely fall 

[Lozz196]

Why not contact Ashdown and ask for their opinions - give the workshop a call, Dave who works there is a gem, really helpful and should be able to offer the best solution for the cab.

[Twincam]

Certainly you could replace the drivers with something that works better in that cab. You would have to calculate cab volume etc then model different driver specs. 

Yes you could self port too, but you would need to do a bit more work. 

After doing some very diy experiments porting things myself just for fun rather than out of need. I found it's a very steep learning curve. 

[gpw5150]

Any thoughts on this as a bass driver; https://www.lean-business.co.uk/eshop/faital-pro-8fe200-8ohm-8-150watt-speaker-p-2276:8d6ac59af11625534a44172ce1f6c7a9.html?zenid=ia3g2j1j418tlso6sdg387b8j4

 

[Sibob]

I moved away from the Ashdown 4x8 many years ago for this reason, that said, my old 4x8 was rear ported?! Although I was always doing gigs where having my cab as flat to the wall as possible was necessary, so may as well have been sealed.

Just front ported cabs for me now.

Si

[TheGreek]

Before spending any money I'd take Lozz's advice and get in contact with Ashdown directly. They are members here. @Ashdown Engineering

The customer service is some of the best in the industry - they can give you advice or failing this they'll do the work themselves at little or no charge. .

[Matt P]

If you can get some accurate internal measurements then you could put the numbers into WinISD (which is free) and this will give you an idea of what the current tuning is like, it should then offer you some dimensions etc for porting and show you what the frequency response will be ported. this would be a totally free way to see what adding a port or two would do to the cab. if you post the dimensions on here then someone else might be kind enough to run the numbers and advise you. (i have the software but am not an expert.)

which Ashdown cab is this? i had a Neo loaded mini ABM 4x8 many years ago and really liked it. a quick google throws up quite a few different ones. (mine had 2 ports on the rear and a varnish finish rather than vinyl.) some appear to have the speakers offset and are taller than they are wide, mine was pretty much square. 

 

Matt

 

[gpw5150]

@Matt P Do you have a link to the WinISD download?

I think this is an early cab - TF0818 drivers, no porting - offset drivers and a horn switch (high/off/low).  Rubber 'fender' handle on the top.

[Matt P]

WinISD is available HERE  it's not that difficult to set up, i've managed to model a few different cabs but i never got round to actually building anything.

 

matt 

[Bill Fitzmaurice]

2 hours ago, gpw5150 said:

Any thoughts on this as a bass driver; https://www.lean-business.co.uk/eshop/faital-pro-8fe200-8ohm-8-150watt-speaker-p-2276:8d6ac59af11625534a44172ce1f6c7a9.html?zenid=ia3g2j1j418tlso6sdg387b8j4

 

It's considerably better than the Celestion, which should never have been loaded in a sealed cab for bass to begin with, but still limited in low frequency capability. I wouldn't consider anything with a higher than 60Hz Fs, and of course the rest of the specs would have to work in the intended enclosure.

[stevie]

The problem isn't with the Celestion driver itself; it's just that it's been crammed into too small a box. I had the 15" version of this cab and I'm pretty sure the internal volume was 50 litres. So you need to find an 8" driver that will perform well in a volume of around 12 litres.

[gpw5150]

So, I modelled it;  Have no idea what I am doing!  I made the volume 84 litres of the box.

Thin Green is ported to 10cm with the SFE-200 driver - VAS 13.6 l

Thick Green is ported to 10cm with the  TF0818 - VAS 9.4 l

Red is sealed with the SFE-200 driver VAS 13.6 l

Blue is sealed with the Eminence Alpha VAS 17.1 l

Lower Blue is the TF0818 driver sealed - as is now.

The box resonance drops to 40Hz ported.

 

Edited October 29, 2018 by gpw5150

[gpw5150]

Porting would be a 10cm hole with an 8cm tube....

[Bill Fitzmaurice]

This is what's possible with an eight that's well suited for electric bass, in this case the B&C 8BG51, in 18 liters net, ported, tuned to 50Hz:

[gpw5150]

3 minutes ago, Bill Fitzmaurice said:

This is what's possible with an eight that's well suited for electric bass, in this case the B&C 8BG51, in 18 liters net, ported, tuned to 50Hz:

Thanks Bill, so my current cab volume is 84 litres, therefore i have 21 litres per driver - assume the above is with those specs and a 10cm port?

[Bill Fitzmaurice]

You don't have 21L per driver as the port and drivers take up volume. You'd model it in your case with 4 drivers. A pair of 10cm ID ports would give acceptable port velocity. With a 70L net cab volume they'd be 20cm deep. You have to figure out what volume they occupy, plus a liter each for the drivers, to find the remaining net box volume. Then you'd do any further adjustment of that box volume in the model to see any required lengthening or shortening of the ports. Don't sweat getting it all perfect, a tolerance of 5% or so in either direction is OK.

[Twincam]

1 hour ago, gpw5150 said:

So, I modelled it;  Have no idea what I am doing!  I made the volume 84 litres of the box.

Thin Green is ported to 10cm with the SFE-200 driver - VAS 13.6 l

Thick Green is ported to 10cm with the  TF0818 - VAS 9.4 l

Red is sealed with the SFE-200 driver VAS 13.6 l

Blue is sealed with the Eminence Alpha VAS 17.1 l

Lower Blue is the TF0818 driver sealed - as is now.

The box resonance drops to 40Hz ported.

 

Did you model it sealed with the faital pro drivers you mentioned? 

[gpw5150]

@Twincam Yes, red line.  I amguessing it just indicates extended range from the lower blie line - tf0818 drivers

Edited October 29, 2018 by gpw5150

[Twincam]

2 minutes ago, gpw5150 said:

@Twincam Yes, red 

I'm not sure about those calculations but the faital pro 8fe200 looks a big improvement over what's in there now. 

 

 

 

[gpw5150]

20 hours ago, Twincam said:

I'm not sure about those calculations but the faital pro 8fe200 looks a big improvement over what's in there now. 

 

 

 

Wondering if i can tune the port better....

[Bill Fitzmaurice]

On 30/10/2018 at 10:44, gpw5150 said:

Wondering if i can tune the port better....

50Hz tuning would be better, but you can't change the driver specs with tuning, and that's why I would not use any of those drivers, other than the B&C I posted, in a stand alone bass cab. I'd only use them in a PA system where they don't operate below 100Hz, that range being handled by sub woofers.

Edited December 13, 2018 by Bill Fitzmaurice

[gpw5150]

Thanks @Bill Fitzmaurice - I am not sure I am in the zone to spend on the B&C, but considering the SFE-200 are £26 each, I can sort the entire cab for ~£100.  I think it is a case of figuring out venting for best performance and living with it.  I.e. improvement for minimum investment!  IN WinISD, how do I model the port?

[Bill Fitzmaurice]

The program models the port, you just enter the desired resonant frequency.

[gpw5150]

Thanks Bill - May I take the opportunity to thank you for your help, not often I get to interact with an industry legend.

Messing with the model tonight shows that porting the box with the original drivers seems to be the best option;  Thick green line;  The SFE-200 seems to go bonkers vented (thin green line), but be far better sealed