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A 1x12, or maybe two


Gottastopbuyinggear
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A quick update on this. First, I've made the frame and added the grille cloth. It's not perfect, but it's turned out better than I hoped and is pretty straight. It's actually a really snug fit, so it's not held in by anything but doesn't fall out. I've added a couple of loops of webbing at the bottom to grab hold of to pull the grille out, though you can't really see that as the photo's a bit poor:

[url="http://s1172.photobucket.com/user/andrewjdowden/media/1x12%20Build/IMG_0481_zpskvm7xe4w.jpg.html"][/url]

More importantly, though, I'm now ever happier with the sound I'm getting from this. I used it last night with my Ampeg PF500 for the first time, having used it about half a dozen times with a GK MB200. I'm not sure whether it's the amp (set pretty much completely flat), the fact that I've just put some La Bella flats on my Precision in place of the D'Addario Chromes I had before, or maybe the speaker breaking in (if you believe in that sort of thing...), but I can't now detect any drop off in the bass as you go down the E string.

All in all I'm still really pleased, and for anyone considering a build based on the information that's in the Basschat 1x12 thread I'd say go for it!

Now I've just got to find some time to finish the second one...

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  • 4 weeks later...

Hi All,
I have just ordered Beyma SM212 from Bluearan and I note that some of the sepecs have changed from those used by Phil &Co on the original Basschat 12 thread.
Spec now
Xmax 8.25
Vd 435ccs
Freq range 45- 4000Hz
Sensitivity 97dB 1W @ 1m

Is it still okay to use in the Basschat Cab?

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[quote name='JohnDaBass' timestamp='1469727170' post='3100709']
Hi All,
I have just ordered Beyma SM212 from Bluearan and I note that some of the sepecs have changed from those used by Phil &Co on the original Basschat 12 thread.
Spec now
Xmax 8.25
Vd 435ccs
Freq range 45- 4000Hz
Sensitivity 97dB 1W @ 1m

Is it still okay to use in the Basschat Cab?
[/quote]I remember Stevie saying that the spec had changed (for the better) although whether that spec is correct I could not say.

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Hi, I need a new computer, it won't open Beyma's new spec sheet Grrr

Looking at the specs on Blue Aran's website though it looks like they've made some quite extensive changes though with a heavier cone, different voice coil and suspension.

As soon as I get time I'll check the modelling and let you know what I think. My instinct is that using this speaker in a 50l cab tuned to 50Hz is still going to work well but the heavier cone may be less liable to flex, tightening up the bass at the expense of a little treble extension. I'm not committing to anything until I've modelled it though.

I'll post here first then update the design thread.

Edited by Phil Starr
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Hi all, I've just run this through WinISD and had a good look through the specs of both the old and new SM212 drivers.

First I'll deal with the specs above.

Xmax is now 8.25mm up from 7mm, that's entirely down to changing the way they calculate it. They used to use the most pessimistic way of calculating Xmax but now use the rather more optimistic methods used by Eminence and others. Either way it is very good for a driver at this price level.
Vd (total air shifted) is correspondingly increased but nothing has really changed apart from the calculations.
They've changed to a heavier cone which has changed the frequency response a little. The new speaker will give a slightly cleaner and more extended bass, but hardly noticeable unless you put them next to each other IMO. The thicker cone has damped out the 2kHz cone resonance that some of us have noticed in the prototypes. This is probably a good thing but I've got quite fond of the little brightness/slight roughness on some notes. Again this is probably a subtle improvement in the new driver.

The quoted frequency range in Beyma's specs has gone from 45-6000Hz in the old version to 45-4000 in the new driver, actually the frequency response curve is very similar so I don't think that you'd notice any loss of top end apart from the damped cone resonance at 2000Hz.. These figures are at a -10dB level but as the curve isn't flat it's not altogether clear what they are using as the base level. the old driver crosses the 90dB line at 6000 Hz and the new one at 5,500Hz..

Not in the above, but to my mind more significant, is that with changes in the suspension and the cone plus some other tweaking Vas has come down to 103l which means this driver is happier in a smaller cab like the Basschat 12. The result is that the small bass peak of about 2dB in the original is down to 0.5db with the new driver and there's a tiny bit more low bass, perhaps 0.5db at bottom E. You won't notice that but you probably would notice the cleaner bass around 100Hz.

The heavier cone and slightly stiffer suspension also means the midrange efficiency is slightly down.

So, to be fair to Beyma I think what they have done is tweaked a bargain speaker slightly; which makes it more usable in a small cab like my design giving a slightly better (in the sense of flatter) frequency response with almost no penalty to the user. I can't see any reason to change the design at the moment.

I'll post this into the main thread too.

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[quote name='Gottastopbuyinggear' timestamp='1470085240' post='3103227']
Hmm... Two questions spring to mind:

(1) Will I be able to tell if my two drivers, one bought in late April and the other earlier this month, are different specs?
(2) If they are, will that have any impact on how the cabs sound as a pair?
[/quote]

might be worth a few emails to the retailer and/or Beyma. Are there any serial no.s on them?

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I've dropped emails to Beyma and Blue Aran to see if they can help. I'll not have a chance to take a look for serial numbers for a while, though, so I'll wait and see what sort of response I get first.

I think I did a model in WIn ISD as well, so I'll check what parameters I used for that. To be honest the 8.25mm xmax rings a bell, so I'm wondering if the specs changed quite a few months ago.

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That 8.25mm Xmax won't be definitive. That could just be down to changing the way Xmas is calculated. If you've got the new version then check the cone mass you used as that is definitely higher.

I hope in a way that you have the new cone. You like the speaker and it would seem you've tried it out for us. :)

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Beyma have responded to my email, stating: "[font=arial, sans-serif][size=3]The latest update of the SM212 data sheet was in December 2014[/size][/font]", so it seems it was a while ago and I'm pretty sure my two drivers will be identical. I'll have a look at them both when I get the chance, but that'll be a while away yet.

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  • 6 months later...

Here's the source for the grille cloth: http://www.ebay.co.uk/itm/Fender-Black-White-Silver-Grill-Cloth-94x93cm-/162388675451?_trksid=p2141725.m3641.l6368

In fact they're actually wearing perforated steel grilles now, courtesy of speakergrills.co.uk. That was a decision based on the added protection, since they're going in the back of the car with amp, pedalboard, mic stands, floor wedge, plus guitarists gear etc. I'll have to get a couple of pics.

Still very pleased with them. Easily more than enough oomph when used as a pair in my 2 x guitar, keys and drums pub band. Flat response to my ears, plenty of bass. Possibly not for those who like a bit of high end sizzle, but see the guys' new design thread over in amps & cabs if that's a concern!

My Markbass 2x10 was redundant after this build and has just been sold, and I've only been trotting out my Ampeg PF115 when the weather's bad as I didn't have any covers for these. At least, I didn't until: http://www.ebay.co.uk/itm/141784444756?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Chop the handles off those and they fit a treat!

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[quote name='Gottastopbuyinggear' timestamp='1488315914' post='3247906']
I didn't have any covers for these. At least, I didn't until: [url="http://www.ebay.co.uk/itm/141784444756?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT"]http://www.ebay.co.u...K%3AMEBIDX%3AIT[/url]

Chop the handles off those and they fit a treat!
[/quote]

:lol:

Cheers for the info. ;)

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