My tactics for improving vintage 3 way open baffles

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Bumpy

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Re: My tactics for improving vintage 3 way open baffles
« Reply #100 on: 9 Feb 2019, 11:51 am »
Lets look at the Bass driver amps etc. which will be run independently of the mid and tweeter.

I am taking a separate output from the speaker terminals of my power amp. It's difficult to get a real fix on the voltages involved but Googling reveals between 20 and 40 volts. This will need to be knocked back to 2 volts which is typical of line level.  As a reality check, it seems that most sub manufacturers build this into their kit, hence allowing a high level input in addition to the line level input.

A forum friend has purchased for me a unit like this.



https://www.ebay.co.uk/itm/SPEAKER-TO-RCA-CONVERTER-HIGH-TO-LOW-LINE-LEVEL-ADJUSTABLE-ADAPTER-2-CHANNEL/361987845604?hash=item5448282de4:g:gPoAAOSw~o5ahv5-:rk:5:pf:1&frcectupt=true

It looks to be suitable but with a 40 to 1 reduction he has modified that to just 20 to 1 with a change of resistors. I should get it in the post next week hopefully with a diagram of whats inside :)

If this works OK by feeding the resultant signal to a Rotel integrated amp then I am good to go on ordering the MiniDSP to set up a low pass filter.

Long term there may be higher quality speaker to line level converters that I can get, but for now its a step forwards.

Bumpy

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Re: My tactics for improving vintage 3 way open baffles
« Reply #101 on: 18 Feb 2019, 11:33 am »
My matching super tweeters are now in place. The mounting is intended to get the voice coils of all drivers close and in the same vocal plane.

Initially they are upward firing and a variety of caps are available to set the high pass frequency. Let the experiments begin. :)




Bumpy

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Re: My tactics for improving vintage 3 way open baffles
« Reply #102 on: 18 Feb 2019, 05:56 pm »
Result.

With a 0.47uF capacitor they have slipped into the OBs perfectly. Their presence can’t be detected, but there is an additional ‘air’ to the presentation which I like a lot. I suspect as they run in, there may be further gains.

Happy boy. Thanks Matevana for the recommendation

Bumpy

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Re: My tactics for improving vintage 3 way open baffles
« Reply #103 on: 14 Apr 2019, 12:21 pm »
I am now looking to improve the 4" high frequency drivers.

I have available vintage Alnico drivers including Saba, 'small' magnet Grundigs, larger magnet Grundigs and my latest purchase is a pair of Klangfilm drivers. These have BIG horse shoe magnets (see picture)

If the weight of drivers correlates to the weigh of the Alnico magnets there is an interesting comparison.

Sabas  105gm
'Small' magnet Grundigs 236gm
Larger magnet Grundigs 330gm
Klangfilm 555gm





FullRangeMan

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Re: My tactics for improving vintage 3 way open baffles
« Reply #104 on: 14 Apr 2019, 02:46 pm »

Wow, looks a great driver large magnet, how is the sound from this driver?

Bumpy

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Re: My tactics for improving vintage 3 way open baffles
« Reply #105 on: 14 Apr 2019, 02:58 pm »
Just got them and at present I have only checked that they are working OK. Certainly sound more alive than the Grundigs they will replace.

They don’t have screw holes, so I need to find a way to mount them. :)

FullRangeMan

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Re: My tactics for improving vintage 3 way open baffles
« Reply #106 on: 14 Apr 2019, 03:17 pm »
The pressure ring dont came with the driver?
The magnet cover cant be put near metal.

Bumpy

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Re: My tactics for improving vintage 3 way open baffles
« Reply #107 on: 14 Apr 2019, 03:46 pm »
The pressure ring dont came with the driver?
The magnet cover cant be put near metal.

No there isn’t a pressure ring, but the drivers are probably 65 years old so they went missing along the way.

My drivers are recessed into the baffle from the rear so may hold them in place with a rubber strap stretched across the magnet and fixed into the rear of the baffle either side of the driver.


FullRangeMan

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Re: My tactics for improving vintage 3 way open baffles
« Reply #108 on: 14 Apr 2019, 03:53 pm »
Wood or alu rings are the material less prone to disturb the magnet.

Bumpy

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Re: My tactics for improving vintage 3 way open baffles
« Reply #109 on: 14 Apr 2019, 04:01 pm »
Good suggestion. I am currently thinking something like this. https://allensportsusa.com/products/4-rubber-straps.

This will also add some damping.

FullRangeMan

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Re: My tactics for improving vintage 3 way open baffles
« Reply #110 on: 14 Apr 2019, 04:25 pm »
How these belts could be implemented?

Bumpy

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Re: My tactics for improving vintage 3 way open baffles
« Reply #111 on: 14 Apr 2019, 09:52 pm »
How these belts could be implemented?

I will post a picture when I experiment later.

Bumpy

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Re: My tactics for improving vintage 3 way open baffles
« Reply #112 on: 18 Apr 2019, 02:17 pm »
Here's a picture of a cobbled together prototype.



« Last Edit: 18 Apr 2019, 03:29 pm by Bumpy »

FullRangeMan

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Re: My tactics for improving vintage 3 way open baffles
« Reply #113 on: 18 Apr 2019, 04:16 pm »
Hm, there is any photo from the face cone side?

Bumpy

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Re: My tactics for improving vintage 3 way open baffles
« Reply #114 on: 18 Apr 2019, 05:48 pm »
Hm, there is any photo from the face cone side?

There will be one along later :)

FullRangeMan

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Re: My tactics for improving vintage 3 way open baffles
« Reply #115 on: 18 Apr 2019, 05:51 pm »
There is any space for metal clamps?

Bumpy

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Re: My tactics for improving vintage 3 way open baffles
« Reply #116 on: 19 Apr 2019, 07:22 am »
There is any space for metal clamps?

No room for metal clamps in my baffle, but this system will work out ideal. From the front one would never know.