Mission 720 bass unit repair

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Contact Mission directly at UK.
They will help you if they have stock of those drivers.
They are VERY helpful.
I just bought some replacement drivers for my Mission speaker.

Alternatively you can buy replacement surrounds ( preferably rubber ) from the web and use them to fix the driver. Driver parameters will change. But we did this to some Dynaudio 12 inch woofers whose foam surround rotted in less than 2 years. So we bought some rubber ones ( bigger than we needed ) and then cut it to size and glued it on. The unit works fine and actually looks better than with the original foam surround. Surround was bought in Germany.
I've come up with:

http://www.ampaholics.org.uk/VINTAGE SPEAKERS.htm


LOUD SOUND URL! http://www.rmjloudspeakes.co.uk/



for the UK, but;


will supply from the states do a kit for $35-40 delivered to the UK.

Now i have two follow up questions;

1. is that price approaching that of a replacement driver ? (which i don't seem to be able to source readilly)

2. I've heard that older speakers cannot handle too much power, as voice coil glue technology, etc was not so good a few years back. So was wondering if a modern equivalent driver may have other advantages over a repaired original? which would justify extra cost, although if TB, etc do something suitable that would prob work out cheaper than the newfoam kit anyway, i guess :confused:

TIA Mark
right, we're probably going for the new surround option because we feel:

Mission relacement drivers will be NOS, so the surround of the 'new' driver will be as old as the rotten one we have.

OEM drivers are not 'generally', good value for money.

better value can be had from replacement drivers, although no options have been suggested yet i.e. NO $35 - $40 replacement drivers have yet to grace this thread..........let alone ones that have good recommendation in terms of sound quality.

please tell us we're wrong b4 we opt for the new 'newfoam' surrounds.....

cheers Mark
Mark, can you give me the diameter of the edge of the cone and also the inner edge of the frame of the speaker ( where the foam was originally glued). I might be able to find a low cost rubber surround for it in our local market. I have someone who is going back to London late next month. He can mail it to you locally.
They don't cost much here. Maybe $2 for a pair !
But the size has to be right.
Let me know if you are interested.

I'm the owner of these speakers that Mark is helping me renovate. Unfortunately, Newfoam have advised that Mission used unusual sizes and they can't supply a surround which would match.

Ashok, thanks for your kind offer. The details of the surround are as follows:

Outer diameter of original surround: 9 3/4"
Inner diameter of original surround: 6 1/2"

Inner diameter of speaker frame: 8 3/4"
Outer diameter of speaker cone: 7 1/8"

The cone doesn't have a flat section, it's a constant taper to the dust caps. If you could have a look to see if there's anything that would match it would be very much appreciated.

BassAwdyO, just in case you can find a replacement driver which you think would be suitable, there is some info regarding the original specifications on the Mission website at http://www.mission.co.uk/archive/Org700series/710_720_730.pdf

Thanks in advance

Hold on..

Hi Greg,
I haven't been to the market yet . My contact will be in India only on the 14th of this month and will be here for two weeks I think.
Even if the local surround is not exact , we can hope it is bigger because you can cut it and get the size you want. I did that for the Dynaudio subwoofer. Works very well.

I should be going to the market before the weekend. Our day time temperatures are close to 40 Deg C every day for the past one week . It's not just hot for you guys it's hot for us too ! VERY hot !
We already had a few 42 deg C days. Can't move around much in that heat.
well from what I found looking at the specs is that the driver is 250mm or ~10" with 86db efficiency crossed over at 700hz.

Info about the enclosure would be very helpful also, but all I could get out of the manual was "3-way infinite baffle"

So is it in IB speaker... or is infinite baffle the british way of saying a sealed box or acoustic suspension? Or maybe even open baffle?

Anyways.... if the owner could please submit any information about enclosure size that would be of great help. Also if you really want to make this sound golden take a look at the crossover and see how it's layed out.

I think a replacement driver would do a superb job in this case. A 10" would probably fit with only minor hole size adjustment. Finding a driver efficient enough is NO PROBLEM, and finding a 10" that plays up to 700hz is NO PROBLEM. The only thing there would really be to worry about is the enclosure/driver combo and it's resultant LF response, but there are sooooo many 10" speakers available that I'm sure we could find one that would work nicely with the box and probably even add a bit of LF extension, clarity, and detail in the lower register
So its a sealed box?

A few more questions....

How much might you be willing to spend on replacing the driver?
Where would be a good place for you to get it (what brands are available in your part of the world).

Just off the top of my head Peerless makes some 10" woofers I think one called CC and CSX which are relatively inexpensive (less than $70 U.S.) which might not be too far off....

Any thoughts mark?
Great idea to replace the driver with a low cost substitute . However the end result might not be exactly like the original. Might involve more work trying to get that to work properly if it turns out to be a problem.

Having gone through several similar situations earlier , I now always try to fix what is already there because 1. I learn a lot more doing it 2. It is fun and 3. It costs much less . I'd put the money saved into more music.
If it doesn't work , then I'd opt for a replacement and wouldn't have lost much money in the meantime.

Both ways you will need to spend some time on the repair. It normally is not a drop in replacement .
So.... you guys are still wanting to replace the surround? Good luck

No, i normally goto wilmslow audio for this sort of thing, they usually have a replacement which is tried and tested to a greater or lesser extent.

I see they carry many brands which are well regarded by many here.... If that surround replacement doesnt work out. It would be no problem replacing it. If you find something with more excursion, lower Fs, and less voice coil inductance you will probably like it better than the original 250mm Plastiflex driver
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