Bassman Rich

What are the dimensions of the cab please ??

I had to change the output jack, thought I'd share these pictures of how it's aging. I think it's a 1983/4, s/n is an E31****

Absolutely stunning amps, and for that money, a steal. If I didn't already have two, I'd be all over that... 

On 24/09/2024 at 07:31, Phil Starr said:

It is possible to measure the behaviour of your speakers and then calculate the Thiele Small parameters using software like REW https://www.roomeqwizard.com/ It is moderately complex and you'll need to make up some test leads but perfectly feasable at home. The results will probably be as/more accurate than the manufacturers tests as published. As usual You Tube is your friend.

 

Thanks for that Phil, sadly, I don't have any focusrite type interface, but after retiring from being an electronic engineer for nearly 40 years, and having my kit provided, I have bought myself a Fluke 75, the Fender USA P bass of test meters.

Quick update. 

Thanks to the brilliant guys at Ashdown, I had a long chat about this with their chief designer, Dave Green. 

He has been trying to do this for quite some time too. 

Got some experiments to do with a bit of cardboard tube, so it just might work. 

BTW the speakers are not the Sica/Jensen ones we thought they were, and the parameters are not accurately known. 

On 17/08/2024 at 07:01, Dolando said:

Pickup arrived!  Custom order from Bareknuckle with aged grey bobbins! 
 

All in the details! 
 

 

 

This pickup looks great. 

I have a Pink Paisley jap reissue tele bass, and the neck is as good as any of my 3 USA P basses. 

However, the stock pickup, plus the Seymore Duncan 1/4 pounder is not great, the pole pieces are such that the highest one ( one in from the left on your photo) is under the A string, so the D string is unusually quiet compared to the other 3. Think I need to get in touch with bare knuckle. 

54 minutes ago, Phil Starr said:

Rounded off it's 57 litres, I calculated based on 53 litres allowing 4l for the volume of two speakers and the port plus any bracing. I also assumed the wall of the port was 2mm. I also looked at the tuning with no port and the 75mm hole. It's tuned too high but you still have the problem of port velocity and it just changes the point where the cone goes into over excursion. Hence your experience just trying it as it is.

 

Love this 😂

 

If you are playing with this cab at home and at reasonable volumes then just enjoy having some fun with it, try creating a cardboard or even papier mache tube of 35mm and listen to the difference. Just don't take it to a gig and crank it. If you decide it's your dream tone then the two port solution Bill suggested will give you that tone and probably will be reliable but you'll have to take a saw to the cab. You could add some bracing to it at the same time and experiment with damping, it's all good fun but it won't be as saleable if you do modify it.

 

If you want to do the rice test try putting a 50hz signal through the speaker with the volume right down and gradually turn it up listening to the noise from the port, you'll hear the noise at a remarkably low power and that is effectively your new maximum volume.

I cannot emphasise enough how much I appreciate all this effort you guys, Phil and Bill especially, have put into this quest of mine, but thanks again.

As I have 3 other gigable cabs, I think I'm going to do the 'tuba tube port' experiment, will order a port today (blue aran do them cheap as chips) , try it out, and post the results. Can I post a video with sound on here, just so you can all giggle at my playing, and the tuba sounds ?? !!

When all said and done, if I blow the speakers, I can then hunt for some new ones that will match my big deep bass trouser flappy desires in a shallow box that fits the boot of the car dreams !!

8 hours ago, agedhorse said:

Yeah, that would turn an electric bass into a tuba at those velocities

 Oh yes, I love this too, I am the new Herbie Flowers, two instruments for the price of one session guy, available for rent, cheap prices, easy action baby....

3 hours ago, Phil Starr said:

Again Bill has got there first. I've just checked the port velocity, you aren't too far short of a sonic boom I was pushing it at 10cm.

But, just in case I get the fiddle about itch, what length single tube at 75 mm would I use, to possibly get sonic booms?? It sounded OK ish, but uneven, when trying it with no port attached, just the hole, but could just be my ears playing tricks, hearing what they want to hear... 

Ps all, I did enjoy watching this guy, tuning his cab with rice, sounds like fun !!

50 minutes ago, Phil Starr said:

Again Bill has got there first. I've just checked the port velocity, you aren't too far short of a sonic boom I was pushing it at 10cm.

My other half often complains about my rear port velocity, and sonic booms, better not upset the apple cart any more  😉

1 hour ago, Bill Fitzmaurice said:

That diameter is far too small, so you'd end up with port air mass velocity that's too high, resulting in port noise. For two tens in an average size cab with 50Hz tuning the minimum required port diameter is 12 cm, or a pair of 8.5 cm. 

Great stuff Bill, however disappointing. Thanks so much to you and @Phil Starr, you guys really know your stuff. 

I guess thats why my ABM 1 x 15 speaker has two 75mm ports on the back.

17 minutes ago, Bassman Rich said:

Hey, fantastic response, they look almost the same. 

The magnet is not quite the same size as on your Jenson spec sheet, about 130mm full width ot the outside of the magnet, as far as I can measure with a ruler.. 

55 minutes ago, DGBass said:

Ashdown used a lot of Sica stuff in their 2x10 300w  and 4x10 600 watt cabs, 10" 150 watt 8 ohm and 16 ohm variants. This link might give you a basic idea of parameters you could try when modelling a ported solution. The Sica BP10/150 is probably as near as you'll get to the OEM version Ashdown used in some cabs, assuming Ashdown can't supply you with the parameters of the drivers in your RM cab. Again, its only a rough guide and no guarantees as OEM drivers could be specified differently from retail versions. The Ashdown Sica's of the time look identical( but probably aren't exactly the same) to the BP10/150 but with the blue ashdown label on the back.

 

https://sica.it/wp-content/uploads/2021/02/ZJ05820.pdf

Hey, fantastic response, they look almost the same. 

19 minutes ago, Phil Starr said:

Exactly this, without the parameters you are down to guesswork. There are drivers designed for ported enclosures and drivers that won't work well plus a few 'general purpose' drivers that will work in either, the problem is that without the specs you can't do the modelling. It's possible Ashdown didn't match their speakers to the cab but more likely that they did.

 

The things that can go wrong with mis-matched drivers are well explained in the previous six pages of woe and blown speakers. Power handling is reduced in a mismatched cab. It could be OK but no-one can be sure so you'd be taking a bit of a risk. If you really want to do this then your cab is just over 50litres and  10CM dia port 11cm long would tune it to 50Hz. You might be better off selling the cab and buying one that sounds the way you want but if you are a tinkerer then I know no advice will stop you from trying it. Good luck, you might like the result but message me if you do blow the speakers and we can look to see if we can find replacements

 

Ooh thanks ever so much. I don't really want to hack the cab about, so can't really increase the port diameter from 7.5cm. I don't suppose you could advise on port length for that diameter could you?? 

Pics of cab added. 

Ps The upstairs loo has stopped flushing, and the bedroom TV broke on Monday (after absolutely years of service, it's a 23" one) new one arrives this afternoon, so might not get to experiment with cardboard tubes for a day or two.... 

2 hours ago, Phil Starr said:

Hi Rich, without the Thiele Small parameters you won't be able to calculate a port length with any reliability and if the cab wasn't ported originally the speakers may not be suitable for a ported cab. Your best bet would be to simply cover the hole with a piece of plywood, so long as it is properly airtight the cab is restored to it's original design as far as the speakers are concerned. If you did want to port the cab I'd probably risk tuning it to 50Hz as the resonant frequency of the speakers will probably be around that area, no guarantee though.

 

Ashdown are probably the best though when it comes to after sales and they might cough up the Thiele Small figures if you email them. Equally they might not want to share that information as it would be potentially commercially sensitive.

Part of me wanting to remove the tweeter, was to get a bit more ooomph out of the cab, and removing the tweeter, effectively front porting was a 'win win' way of both doing this, and lightening the cab.

Also, as the front speakers and port will be behind the snazzy new silver grill Ashdown use for the RM III models, it wont need to be a pro finish visible job, just do the business audiably

16 minutes ago, bremen said:

I've been using  the alpha version, beta was extremely buggy last time I tried it. Is it any better now?

 

https://loudspeakerdatabase.com/

 

is, as you'd hope, a wonderful resource. It exports thiele/small parameters to win ISD (or several other apps)

Thanks, much appreciated. 

I'll have a go , see how I get on, expect me back asking you and @bremen questions real sooon !!!

1 hour ago, Phil Starr said:

Win ISD is found here http://www.linearteam.org/

 

It's a really good resource provided for free so well worth donating to

Thanks, much appreciated.

On 12/10/2013 at 14:57, Phil Starr said:

[quote name='alexclaber' timestamp='1380620797' post='2227845']
The driver in question is excellent for bass guitar. The damage is a clear case of both excursion and thermal overpowering. Most cheap bass cabs are tuned too high which means they'll unload on low note fundamentals.
[/quote]
[quote name='Bill Fitzmaurice' timestamp='1380630582' post='2228069']
+1. As is the case with any and all drivers it must be loaded into a cab that is compatible with its specs. If one is to push it to maximum output the amp must at the very least be appropriately high passed, if not limited to the driver's safe operating voltage swing.
In terms of performance the 3015 is on par with an Aston Martin.
[/quote]
[quote name='R Baer' timestamp='1381186373' post='2235685']
+1 The 3015 is a great driver for a bass cabinet. Per the Eminence website "Recommended for vented professional audio enclosures for full range...." Full range would include a bass cab as well. Pretty much any driver can be pushed too hard into over-excursion, or fed enough power to burn out the voice coil. In my experience, there is a tendency for the term "super 12" or "super 15" to be taken as meaning these cabinets are capable of handling anything you can throw at them. Regardless of how well they perform, every cab does in fact has it's limits.
[/quote]

So it is absolutely clear that this speaker is a great choice for bass, Alex Claber, Bill FitzMautice and Roger Baer all agreeing, and full range does mean including bass. it is also clear that the damage was caused by over excursion from the photo's provided by Blue Aran.

The big question then is: was this a suitable cab? To settle this I modelled the cab with WinISD using data from the Warwick website. The cab is just over 140l and tuned to 35Hz.

The frequency plot is poor, the cab rolls off starting at 500Hz and is 6db down at bottom E. This is due to over damping from too large an air mass. A smaller cab would give much better bass. the crucial plot is the excursion plot however. If excursion is in excess of 11mm within the pass band then the failure is due to the cab design. If it is not, the failure is due to something else.

I've attached the plot. This is with 450W power. The Warwick trace is in blue/green the other is Eminence's cab, similar in size to the Compact. You can see the unsuitability of the larger cab, the Compact sized cab keeps excursion within 6mm down to 35Hz the Warwick cab allows the excursion to rise to 10mm in the 'critical 60Hz region' meaning the bass will be distorted due to the misalignment of the port, which is tuned too low for this speaker. Both speakers exceed the damage excursion below 30Hz, though the Warwick is slightly better in this area than the smaller cab.

This wasn't by any means a good choice of cab, it is designed for a speaker with a lower Fs and less well damped than the 3015, a smaller cab tuned to 45Hz would have been better. But, this speaker, in this cab using the full power of the SWR should not have been hitting the back of the magnet as it seems to have done. I guess it was out of manufacturing tolerance.

Hi Phil

Very informative post, I wonder if you could help me please. Do you have a link to the speaker/cab modelling site pleas, i'm trying to remove a tweeter from an Ashdown RMIII 2 x 10, not only to make it lighter (I never use the tweeter), but could do with advice as to how to 'tune' the now front ported cab. I'm hoping its just fit a tube of a certain length to the cab, which is braced, and has some acoustic wadding in, and is 445 x 465 x 275 mm internal dimensions, 75 mm dia 'front port' hole. I have no idea what the speakers are, just an Ashdown sticker, ASH/10/16/150/BLACK  2311 (which I assume to mean Ashdown speaker, 10 ", 16 ohm, 150 Watt, black cone , manufactured Nov 2023 )

On 20/08/2024 at 04:19, Bill Fitzmaurice said:

It does, but it doesn't matter. Low frequency projection is 360 degrees. That means rear ports project as much sound to the front as they do the back. By the same token front ports, and for that matter the cone,  project as much sound to the back as they do the front. Dispersion only narrows to 180 degrees when the baffle width is one wavelength. At 100Hz that's 3.4 meters. At 50Hz it's 6.8 meters.

Thanks Bill. It sounds completely bonkers, but that's what science is for, making sense out of what originally seems madness. I tested out (without knowing this stuff) an 8 x 10 cab at our rehearsal room last night, it seemed louder, or at least as loud, when I was at nearly 70-80 degrees around from the front, rather than directly in front !!

22 hours ago, Rich said:

When I was car shopping I had to strike the utterly gorgeous Giulia off my list because the boot aperture was 1/2" too small to get my cab in. I nearly cried.

I prioritised the car over the cab, atm, the cab goes on the back seat !!!

On 04/02/2024 at 04:57, DGBass said:

Sadly, that type of sound is a dying breed these days.  @Phil Starr was on to something when he talked about fashions and trends. The choice of speakers for compact high performance light weight cabs almost dictates the use of 10 or 12 inch drivers and that affects the tonality.  Most 15 inch high performance drivers that can deliver a substantial "thud" or "thump" as I prefer to descibe it will need a certain cabinet volume to work efficiently and at their best performance. The reality is that 1x15 cabs designated as high performance aren't very compact. If that was possible, I'm sure we would have seen a compact lightweight 1x15 thread here on basschat that delivered a useable build plan to conclusion. If there is one I may have missed it?  And that's why there aren't so many of them around in the commerical market. The only one I've found interesting is the Mesa Subway 1x15 and thats because of previous experience with the high quality of Mesa cabs. But it costs nearly £1000.  I've gone the lightweight route and found that modern boutique 2x10's still can't emulate the mid sucking thump a good vintage 1x15 cab can.

I'll admit I'm firmly routed in the past as far as thud and thump are concerend and use a 44 year old Musicman RH115 made of solid pine but loaded with a state of the art Lavoce Neo driver. It weight in at 23kg, is a one handed lift and has that old school thud and thump in spades. The point here is that maybe an old school cab is worth hanging onto just to get that sound and maybe a modern driver upgrade will help lighten the load and be less expensive than shelling out a grand or more for a modern 2x10 cab or a 1x12?  An SVT 810 is around 64kg. I mean, thats weighty. You could easily shell out a grand or more for some of the recommended modern lightwieght compact cabs that are always mentioned in these type of threads. There is a lot of scope available in a cab that weighs less than an svt810. For example, you could pick up a good Trace Elliot 1518 cab for around £50 that weighs 39kg but will have thud and thump by the shedload. Neo drivers don't really make much difference tonally, its all about the weight. I sort of wish when recommendations are made for boutique modern lightweight cabs that folks wound prepend a recommendation with the line "if you have a grand or more to spare, why don't you check out x cab from y manufacturer. It keeps things real.  I love that old school thud and thump, a p-bass with flats and a large booming 1x15 cab. You wont ever be able to emulate that with a 1x12 or a 2x10. Yes, you might be able to move as much air, but the tonality will be different. I've tried for years and never come close. Open to any recommendations though with potential costs attached🙂 

DGBass

That low end dirty thump of an old school cab is EXACTLY the sound I want (and get from my Ashdown compact 1 x 15 cabs, with Eminence 3015s in) but they are too deep to fit in the boot of my car, as I've mentioned on another thread. The Mesa Subway cabs look incredibly well built, and being front ported, even better, but sadly, they too are too deep for me. I wonder if I could just make a cab thats a bit higher and wider, but not as deep, whether that would achieve the same sonic results......??

I feel a little project coming on, the wood and glue shouldn't be that expensive..

On 29/06/2023 at 21:03, cd_david said:

Thanks! I’ve had a few of the vertical 215s but the slightly newer ones with the removable front panels. Great sounding cabs. 

I used to use a pair of those 2 x 15 vertical cabs, again as David said, with the removable fronts. Got decent ooomph from a Marshall 50 w valve amp powering both.

On 28/05/2024 at 22:53, warwickhunt said:

Why front porting specifically?  It has no impact on sound projection etc.

This could very well be a numpty question, but here goes...

Doesn't it project sound behind the cab, ie towards the back corner of the room, where the band are, rather than forward, towards the audience ??

3 hours ago, Phil Starr said:

We will need the internal dimensions of your boot for our calculations 😂

Hahaha glad you found my tongue in cheek post amusing, and replied in the same vein.

In my Alfa Giulia, amazingly, in a soft gig bag, the bass sitting in the same position as it is when you play it, just fits in the boot diagonally, but only 'standing up' not laying down !!

Boot is a whopping 480 litres, but can't fit the Ashdown compact cabs in, as they are too deep. Max cab depth would be around 36cm, so still looking, the Ashdown 2x10 rootmaster III cab fits, but being sealed, and small, lacks enough ooomph for all but the smallest gig. The eternal search continues...

https://www.parkers.co.uk/alfa-romeo/giulia/review/practicality/