Replacement speaker for GK MBE212

[lagartortazo]

[color=#191919][font=Verdana, Arial, sans-serif][size=4]Hi, in the last days I have noticed that my GK MBE212 4ohm cab is making some buzz when the amp head is past half volume, on the low notes. I checked and it seems that the noise is coming for one of the speakers, so I think it needs to be changed, but I have no posibility to get a replace of the same speaker.[/size][/font][/color]

[color=#191919][font=Verdana, Arial, sans-serif][size=4]I would need some help to choose another, at the moment I'm looking at Eminence Beta 12A-2, Delta 12A or 12LFA, Gamma 12A, Fame Sovereign 12-300, 12-250TC or Celestion TF1225/1225E...[/size][/font][/color]
[color=#191919][font=Verdana, Arial, sans-serif][size=4]Which one would be better option? Any other one for around same price? Assuming that I'll have to buy two units I can't spend more.[/size][/font][/color]
[color=#191919][font=Verdana, Arial, sans-serif][size=4]I'm not looking for an improve on the cab, just something that sounds more or less similar and without sound problems.[/size][/font][/color]
[color=#191919][font=Verdana, Arial, sans-serif][size=4]Thank you[/size][/font][/color]

Edited March 17, 2017 by lagartortazo

[Bill Fitzmaurice]

Unfortunately without the T/S specs and a response chart of the G-K driver it's a shot in the dark.

[lagartortazo]

Thank you, I understand. It's difficult, I know that it won't be the same, but there must be some that could sound ok...

[Bill Fitzmaurice]

You can use speaker modeling software, like WinISD 0.7, to reverse engineer the cab for the purpose of comparing the low frequency response and maximum output with various drivers, and the driver data sheet SPL charts will tell you the midrange and high frequency response. But you have no way of knowing how they compare to the original drivers.

[lagartortazo]

Thanks again, I've been trying that software, I found it pretty useful.
Any other opinion, experience with any of those speakers will be appreciated

Edited March 17, 2017 by lagartortazo

[Beer of the Bass]

If you can measure the internal dimensions of the cabinet and the diameter and length of any ports, people might feel better equipped to make recommendations.

[lagartortazo]

[quote name='Beer of the Bass' timestamp='1489786048' post='3259933']
If you can measure the internal dimensions of the cabinet and the diameter and length of any ports, people might feel better equipped to make recommendations.
[/quote]

Around 125 litres, and port measurements are 12x24cm
Thank you

[Balcro]

[quote name='lagartortazo' timestamp='1489788265' post='3259960']
Around 125 litres, and port measurements are 12x24cm
Thank you
[/quote]

Using your dimensions, I get a nominal internal volume of about 83 litres. Looking at the GK site for the MBE(ii) the internal dimensions appear to be about 115 litres. In both cases there needs to be an adjustment for the volume occupied by the speakers, bracing, port(one or two) and the drive units. Can you confirm that the dimensions you quoted are internal.

Balcro.

Edited March 17, 2017 by Balcro

[lagartortazo]

Hi, Balcro, thanks for your reply.
It is the first MBE212, and you're right, I did not think about speakers volume, just took measure of dimensions and and calculated litres.

[Phil Starr]

The guys here will work out the tuning for you, I'm going to take a slightly different tack.

Buzzing from a speaker doesn't mean its terminal. possibly the most common cause is something loose in the cab. Check all the screws holding the speaker are tight, that there are no loose joints near the speaker or foreign objects loose inside. Check the speaker cables inside the cab aren't touching the cone.

Now examine the speaker itself, any tears in the cone? examine the dust cap in the middle of the cone, has it come loose? Now work your way round the corrugated surround, has it come away from the speaker frame or from the cone itself.

Just about all of these things are a very simple fix, just re-glue with a latex adhesive like Copydex. If you find anything let us know and we can give details of what to do.

[Phil Starr]

[quote name='lagartortazo' timestamp='1489772699' post='3259774']

[color=#191919][font=Verdana, Arial, sans-serif]I would need some help to choose another, at the moment I'm looking at Eminence Beta 12A-2, Delta 12A or 12LFA, Gamma 12A, Fame Sovereign 12-300, 12-250TC or Celestion TF1225/1225E...[/font][/color]
[color=#191919][font=Verdana, Arial, sans-serif]Which one would be better option? Any other one for around same price? Assuming that I'll have to buy two units I can't spend more.[/font][/color]

[color=#191919][font=Verdana, Arial, sans-serif]Thank you[/font][/color]
[/quote]
The Beta 12A2 is a good choice. The delta has a really strong peak in the frequency response, you might like it but I don't think they sound good for bass, just too coloured. The Gamma isn't good either excursion is too limited for bass. The Fane 12-300 and the two Celestions you mention are designed as the bass driver in PA speakers and will work but aren't ideal for bass. The 250TC is a full range driver, it might sound 'interesting' but again bass isn't what it is designed for. The other speaker to look for is the Beyma SM212 used in a couple of designs here or maybe this http://www.bluearan.co.uk/index.php?id=CELBL12200X&browsemode=category

In the end though I think this would be a mistake. You are putting two different speakers in the same box and they will interact. That means you won't get a predictable sound out front and at the same time the excursion of one speaker will affect that of the other potentially reducing power handling. If there is any difference in their tuning then you can't tune the cab for both speakers at the same time. You really need to replace both speakers at the same time.

I'm hoping you find a fixable problem on you speaker, if not I'd strongly advise you to look into getting another GK speaker, it'll be cheaper in the long run.

[casapete]

[quote name='Phil Starr' timestamp='1489825603' post='3260083']
The guys here will work out the tuning for you, I'm going to take a slightly different tack.

Buzzing from a speaker doesn't mean its terminal. possibly the most common cause is something loose in the cab. Check all the screws holding the speaker are tight, that there are no loose joints near the speaker or foreign objects loose inside. Check the speaker cables inside the cab aren't touching the cone.

Now examine the speaker itself, any tears in the cone? examine the dust cap in the middle of the cone, has it come loose? Now work your way round the corrugated surround, has it come away from the speaker frame or from the cone itself.

Just about all of these things are a very simple fix, just re-glue with a latex adhesive like Copydex. If you find anything let us know and we can give details of what to do.
[/quote]

+1 to all of this.

Also, don't forget that if the speaker is at fault, you can probably get it reconed. Can't remember which thread on
here recently mentioned a couple of places that do reconing, but think it worked out at around £45 plus postage for
a 12" driver. If I find the details will add to this post.

[lagartortazo]

[quote name='Phil Starr' timestamp='1489825603' post='3260083']
The guys here will work out the tuning for you, I'm going to take a slightly different tack.

Buzzing from a speaker doesn't mean its terminal. possibly the most common cause is something loose in the cab. Check all the screws holding the speaker are tight, that there are no loose joints near the speaker or foreign objects loose inside. Check the speaker cables inside the cab aren't touching the cone.

Now examine the speaker itself, any tears in the cone? examine the dust cap in the middle of the cone, has it come loose? Now work your way round the corrugated surround, has it come away from the speaker frame or from the cone itself.

Just about all of these things are a very simple fix, just re-glue with a latex adhesive like Copydex. If you find anything let us know and we can give details of what to do.
[/quote]

Hello, Phil, I already tried all that, and also swapping positions of speakers, I can see clearly that the buzz comes from one of them, although I cannot find any visible damage.

[quote name='Phil Starr' timestamp='1489826765' post='3260096']
The Beta 12A2 is a good choice. The delta has a really strong peak in the frequency response, you might like it but I don't think they sound good for bass, just too coloured. The Gamma isn't good either excursion is too limited for bass. The Fane 12-300 and the two Celestions you mention are designed as the bass driver in PA speakers and will work but aren't ideal for bass. The 250TC is a full range driver, it might sound 'interesting' but again bass isn't what it is designed for. The other speaker to look for is the Beyma SM212 used in a couple of designs here or maybe this [url="http://www.bluearan.co.uk/index.php?id=CELBL12200X&browsemode=category"]http://www.bluearan....semode=category[/url]

In the end though I think this would be a mistake. You are putting two different speakers in the same box and they will interact. That means you won't get a predictable sound out front and at the same time the excursion of one speaker will affect that of the other potentially reducing power handling. If there is any difference in their tuning then you can't tune the cab for both speakers at the same time. You really need to replace both speakers at the same time.

I'm hoping you find a fixable problem on you speaker, if not I'd strongly advise you to look into getting another GK speaker, it'll be cheaper in the long run.
[/quote]

I know that, my plan is replacing both speakers. I can't buy the original GK driver in my country (Spain), the distributor is not providing it anymore.
Thank you very much for your help, by now I think the beta12A2 can be the winner.

[lagartortazo]

[quote name='casapete' timestamp='1489828145' post='3260112']
+1 to all of this.

Also, don't forget that if the speaker is at fault, you can probably get it reconed. Can't remember which thread on
here recently mentioned a couple of places that do reconing, but think it worked out at around £45 plus postage for
a 12" driver. If I find the details will add to this post.
[/quote]
That's another interesting option. Thank you!

[casapete]

Here you go. I'm guessing international postage shouldn't be a problem either.

http://www.audioloudspeakers.co.uk/boultons.shtml

http://www.wembleyloudspeaker.com/

[lagartortazo]

[quote name='casapete' timestamp='1489829469' post='3260124']
Here you go. I'm guessing international postage shouldn't be a problem either.

[url="http://www.audioloudspeakers.co.uk/boultons.shtml"]http://www.audioloud.../boultons.shtml[/url]

[url="http://www.wembleyloudspeaker.com/"]http://www.wembleyloudspeaker.com/[/url]
[/quote]
Great! Really appreciate your help

[casapete]

No problem, hope you get it sorted!

[Beer of the Bass]

Phil's suggestions seem spot-on regarding which speakers would work in that cab volume. You would want to double check the port tuning if you did change speakers - anywhere from 40-50Hz is viable for the Beta 12 or the SM212.
Another possibility; I've noticed that Full Compass in the US carry some GK spares. Is your speaker there?
www.fullcompass.com/brand/GKR_Gallien-Krueger/Replacement-Service-Parts.html

Shipping from the US might be costly, but you would only have to replace one speaker and the cab would retain its value better if you ever sell it.

[lagartortazo]

[quote name='Beer of the Bass' timestamp='1489832849' post='3260155']
Phil's suggestions seem spot-on regarding which speakers would work in that cab volume. You would want to double check the port tuning if you did change speakers - anywhere from 40-50Hz is viable for the Beta 12 or the SM212.
Another possibility; I've noticed that Full Compass in the US carry some GK spares. Is your speaker there?
www.fullcompass.com/brand/GKR_Gallien-Krueger/Replacement-Service-Parts.html

Shipping from the US might be costly, but you would only have to replace one speaker and the cab would retain its value better if you ever sell it.
[/quote]
I couldn't find it on their website, but I sent them an email anyway. Thanks for your help.

[Phil Starr]

Beyma manufacture in Spain, you might get a better price than here. Just a thought. I'd still go for a like for like replacement though.

[lagartortazo]

Price is just a little bit higher than eminence beta 12A2 (15€)

Pros: 350w vs 250w of the eminence, I could push my BH550 head with no fear if I need it (rarely need to go more than half volume)
Cons:
;
Green: Eminence
Pink: Beyma
Of course I can be wrong, I never used WinISD until last night, probably I'm not doing it correctly.
Do you think Beyma can be a better option?
Thanks again

[Balcro]

Hi lagartortazo,

Having checked out all the choices on your list with winISD, I can't find any that produce a good response in
39litres (half the cabinet net volume). As Phil Starr has said, the Beyma 212 works well enough to be usable.
Without touching the existing second port it will have a tuning frequency of about 51Hz.

However, it will change the sound balance of the system because it probably has more low bass than the original GK unit but is probably less efficient (a fraction less loud) overall.

See winISD graph of the Beyma in 39litres of air space. Double click on the attached thumbnail picture.



Over here the Beyma is about €100. You'll have to wait for the reply e-mail to learn the cost of a GK original. Good luck.

[b]PS. Don't forget to check that the speaker mounting holes of any replacement are the same diameter as the GK originals.[/b]

Edited March 19, 2017 by Balcro

[lagartortazo]

Thanks again, Balcro, you're helping me a lot.
I'm waiting for the e-mails back to see if I can replace or fix the original speaker