Newbie - 3 way replacement speakers

Hello everyone

I'm looking for help on replacing an old speaker set.

I have recently gotten an old speaker set from my dad. A pair of AKAI SR-H310's (Photo attached).
As you can see they aren't in the best shape.

I am looking for help on how to replace these speakers and with what speakers I should go with.
Or if it is beter to just buy a kit (speakers and cabinet)?

Info:
Sizes of the speakers:
Tweeter: 65 mm
Mid: 100 mm
Low: 200mm

Impedance: 8 Ohms
Rated power in: 45W
Max. power in: 55W

Couple questions:
I was wondering if it possible to find some replacement speakers to put in the cabinet?
Is it worth looking for replacements or should I buy a kit somewhere?
Are there any sites/service you can recommend on this topic?

Could you guys give me some pointers to where I should look for replacement speakers and what to look out for?
Suggestions are also welcome.

The speakers are going to be hooked up to the AKAI AM-U3 amp.
(See photo attached)

I do not have any experience on this topic so any help would be appreciated.

Thanks in advance
Michiel
 

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Hi, an interesting restoration challenge.

By the looks of things only the bass unit may need a re foam, the mid and tweeter drivers might be fine. If you have no sound from any of the drivers you may have to use a resistance meter to verify that the voice coils are still connected.

Firstly i suspect removing the trim rings will allow you and others here to see what the midrange and tweeter are like. The paper mid may have a paper suspension and hopefully that will be intact. As to the tweeter it maybe another smaller paper driver behind the fancy cover. Some more images will help.

For re foaming the woofer you will have to carefully measure the outer diameter and measure the width of any remaining foam and then measure the diameter of the speaker mounting basket with these dimensions you can at least search to see if a matching dimensions re foam kits exist. Possibly you don't feel confident about doing a re foam, so maybe a friend or local repair shop could do this for you and there are YouTube videos you can watch on how to do this.

If the other drivers are fine, but the refoam doesn't appeal we will have to know the speaker dimension's, easy when you have removed the trim rings to see the chassis. Then you will carefully need to unscrew any other mounting screws and gently ease the speaker out of the chassis to enable you measure the internal cut out dimension's/diameter. Also needed are the box dimensions and the approximate thickness of the box material so people can work out the box volume. Once speaker size and box dimensions are known somebody should be able to suggest a replacement and maybe a tweak to the crossover components.

A quick look on the web suggest its a sealed, 8 ohm design dating from 1982. I haven't looked for further info but maybe some more searching may allow you to gather more information.
 
Hi

Thank you for taking the time to response.

I have attached the pictures without the covers.

I have done some resistance measurements on the terminals and one speaker gives about 9-10 ohms the other gives a infinite resistance value.
I do have the original documentation for the amplifier but nothing on the speakers.
 

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This is something i found on the internet.

Which suggest the Xover shouldn't be difficult to de bug.
If you can find which driver is broken or which wire has fallen off, or a component that gone open circuit that a bit more progress..
 

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Just took out the speakers and one cable was missing from the woofer terminals.

So that is an easy fix to resolder that.
As for the components inside everything seems too look fine (See photo).

I did some measureing on the tweeter and the mid and the resistance seems to be all over the place and not stable.
Am I doing something wrong here?
 

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To verify the drivers impedance or the resistive element you need to measure across the driver terminals without the Xover components being connected. if the driver is not disconnected for the measurement you will see the impedances of the crossover components and the capacitors being charged from the Meter battery which will give you an initial low reading and then very high resistance.
 
Hi

It's been a while.
Sorry for the late reply.

I have measured the woofer foam ring (or whats left of it) and these are the following measurements:

Basket diameter14.8cm
Outer foam ring diameter19.3cm
Width of the foam ring on the outside8mm

Cabinet measurements:
Volume170mm x 265mm x 550mm = 24777500 mm³
Tweeter diameter (hole)94mm
Mid diameter (hole)90mm
Woofer diameter (hole)180mm

Would this foam ring work for the woofer:
Site: Foam ring

1695233435733.png

The exact sizes of this ring are, in CM: 19,25 - 17,85 - 14,8 - 13,7
This surround is angled.
The flexibility of this surround is indicated with number: 2.

Some additional questions:
What would you guys recommend in terms of speakers if I wanted to replace them entirely?
What adhesive do I need to refoam the woofer?
Any precuations I should take?
What sealant is used when mounting the speakers in the cabinet?

Thanks in advance!
Michiel
 
I think that foam you have picked should fit your measurement's and the links you have provided look to be right, although the flexibility property is one that is a bit more tricky, but the value of 2 seems like a sensible choice with the sealed cabinet.
As to suitable glue they should suggest or sell you some with the foam surrounds.

I imagine you could also drop an email to the provider and tell him they are for your particular Akai design, he may have this information in his customer database or his own references. They are usually helpful in my limited experience of re foaming.

As to a suitable replacement for the bass speaker possibly a monacor SPM 205 (89dbs Paper and relatively cheap) or SPH 210, (90 dBs Polypropylene, more expensive, probably better for a completely new design) you will also need to check their dimensions.

There is a Polish drive unit manufacturer STX who may have something in their catalogue see,
https://stx.pl/w-20-80-8-mc.html
They suggest on their website a sealed 25 Litre enclosure, so that good.

There are some caveats here, in that a replacement driver, even if you find one that fits is not going to have the same parameters as the original bass speaker. That's why a re foam is a very sensible option.
Using a different from the original design bass speaker may need some small or worst case large adjustments in the crossover components and there isn't much in the original design to change, and without measurements its a risk, and difficult to suggest anything more than using resistors for some attenuation or increasing the size of the inductor on the new bass driver.

However, if you want to repair these for nostalgic reasons, or you enjoyed the original sound, or simply because they belonged to your father I would look at the paper coned drivers and if they fit make your choice and try them. knowing that you might have to make adjustments

If thinking about a new design there are several here to check out just do a search.

I am also sure there are many German Klang and Ton kits that are also worth studying to understand design and overall costs.