Sony speaker project

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Dr Bunsen Honeydew
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Re: Sony speaker project

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I should add a note, this will increase the weight of the cone lowering efficiency so you may need to increase the value of the padding resistor in front of the tweeter. What ever it is (normally 7 to 10 ohms) increase by up to double, try in stages starting at low value. Three different values should be all you need to try. The higher the value the more the tweeter output will be attenuated.

Wallace (of racing lawnmower fame) has done this to the tweeters in his JPWs so he may want to join in here.

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gus3049
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Re: Sony speaker project

Unread post by gus3049 »

Dr Bunsen Honeydew wrote:I should add a note, this will increase the weight of the cone lowering efficiency so you may need to increase the value of the padding resistor in front of the tweeter. What ever it is (normally 7 to 10 ohms) increase by up to double, try in stages starting at low value. Three different values should be all you need to try. The higher the value the more the tweeter output will be attenuated.

Wallace (of racing lawnmower fame) has done this to the tweeters in his JPWs so he may want to join in here.
Interested in your views about this. My assumption was always that if you wanted to reduce the output of a tweeter, you just add a resistor. However, received wisdom seems to suggest it should be an 'L' pad. This is what I did on one project and it sounds fine although I have no idea how it would measure as I wouldn't know how.

Is there a right and wrong here? Does it sound different? Does it matter if it sounds OK?

floydfan
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Re: Sony speaker project

Unread post by floydfan »

Does not seem to be any resistors in the crossover. It looks like 2 inductors and 1 capacitor in the crossover. There are two coils of wire one marked 0.22mH and the other marked 0.5 with no units. I assumed these were both inductors.
If I dope the bass driver will I have to abandon my plan of just leaving the crossover alone and cutting the bass driver wires and come up with a new plan including a resistor?
Don't know what an L pad is.

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gus3049
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Re: Sony speaker project

Unread post by gus3049 »

Speaker L pad

A speaker L pad is a special configuration of rheostats used to control volume while maintaining a constant load impedance on the output of the audio amplifier.[1] It consists of a parallel and series resistor in an "L" configuration. As one increases in resistance, the other decreases, thus maintaining a constant impedance, at least in one direction.
A constant-impedance load was important in the days of vacuum tube power amplifiers, because such amplifiers often did not work efficiently when terminated into an impedance greatly different than their specified output impedance. This was only true of full range speakers. Most modern applications for full range speakers use tapped transformers. Maintaining constant impedance is less important to modern amplifiers using solid state electronics.


Wiki definition!!

Richard may have some views, maybe the valve amp bit is relevant.

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Dr Bunsen Honeydew
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Re: Sony speaker project

Unread post by Dr Bunsen Honeydew »

gus3049 wrote:
Dr Bunsen Honeydew wrote:I should add a note, this will increase the weight of the cone lowering efficiency so you may need to increase the value of the padding resistor in front of the tweeter. What ever it is (normally 7 to 10 ohms) increase by up to double, try in stages starting at low value. Three different values should be all you need to try. The higher the value the more the tweeter output will be attenuated.

Wallace (of racing lawnmower fame) has done this to the tweeters in his JPWs so he may want to join in here.
Interested in your views about this. My assumption was always that if you wanted to reduce the output of a tweeter, you just add a resistor. However, received wisdom seems to suggest it should be an 'L' pad. This is what I did on one project and it sounds fine although I have no idea how it would measure as I wouldn't know how.

Is there a right and wrong here? Does it sound different? Does it matter if it sounds OK?
No not an L pad - a pad - a series resistor.

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Dr Bunsen Honeydew
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Re: Sony speaker project

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floydfan wrote:Does not seem to be any resistors in the crossover. It looks like 2 inductors and 1 capacitor in the crossover. There are two coils of wire one marked 0.22mH and the other marked 0.5 with no units. I assumed these were both inductors.
If I dope the bass driver will I have to abandon my plan of just leaving the crossover alone and cutting the bass driver wires and come up with a new plan including a resistor?
Don't know what an L pad is.
Gus has created confusion it is just a series resistor you need, forget about L pad.

In the case of your crossover remove it and just put a 3mfd (good quality) capacitor in series with the tweeter and add a series ww resistor (about 5w) change value until the balance drops in with the doped woofer.

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Dr Bunsen Honeydew
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Re: Sony speaker project

Unread post by Dr Bunsen Honeydew »

There is the usual potential of creating confusion here.

So back to basics.

I am only talking about two way speakers.

The mods - remove *all* cabinet damping and line cab with steel plate - remove all crossover components from bass / mid driver and wire it directly to input sockets - remove all crossover component from tweeter and wire direct from terminals with a 3 or 3.3 mfd capacitor in series with a ww resistor in series with that.

Tuning - quantity of dope on bass / mid driver - value of series resistor on tweeter - both as already described - simples.

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gus3049
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Re: Sony speaker project

Unread post by gus3049 »

Dr Bunsen Honeydew wrote:There is the usual potential of creating confusion here.

So back to basics.

I am only talking about two way speakers.

The mods - remove *all* cabinet damping and line cab with steel plate - remove all crossover components from bass / mid driver and wire it directly to input sockets - remove all crossover component from tweeter and wire direct from terminals with a 3 or 3.3 mfd capacitor in series with a ww resistor in series with that.

Tuning - quantity of dope on bass / mid driver - value of series resistor on tweeter - both as already described - simples.
I was rather hoping you would tell me why! Us peasants would like to get even a glimmering of information sometimes. :shock:

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Re: Sony speaker project

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Because it sounds better / makes better music. Why should anyone need to know anything else.

PS I have already explained why before, here and at ask the designer.

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gus3049
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Re: Sony speaker project

Unread post by gus3049 »

Dr Bunsen Honeydew wrote:Because it sounds better / makes better music. Why should anyone need to know anything else.

PS I have already explained why before, here and at ask the designer.
Ah well, some of us are new here and don't necessarily want to read through an entire archive to get info. I realise some people are happy just to drive their car without any idea how it works. Some of us, particularly our generation (we are the same age) would like to know how stuff works and it is part of the pleasure of using things.

Sorry to ask to to repeat stuff but that's what comes of being an oracle 8-)

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