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Help needed to Fix or Repurpose old Speakers
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Old 26th November 2020, 01:19 AM   #91
Galu is offline Galu  Scotland
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There's absolutely no need to test the capacitors. No way will they be faulty!

Run twin flex from the input terminal posts to the woofer terminals then from the woofer to the tweeter, but include the capacitor in the positive wire going to the tweeter. You could simply tape the capacitor securely to the woofer basket in order to support it.

Observe polarity i.e. red to red (+) and black to black (-).

The circuit diagram is shown in the attachment (ignore the values shown), but the physical wiring is as I've described.
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File Type: png Series Capacitor Filter.png (7.9 KB, 63 views)
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Old 26th November 2020, 07:34 PM   #92
NewGuy781 is offline NewGuy781  Italy
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Ok cool, sounds simple enough, thanks!! Had to google what was twin flex hahaha (never heard cables being called like that ).


So basically the wiring/soldering I do it already as its going to be in "the end product, and then once I do the new box I just move it al together right? Or is this just a test setup/dry run?


Also, what do I look for in the sound as far as to tell if something is wrong? I can think about the obvious like over-powering highs compared to lows and vicevesa when listening to music, and distortions; but is there some specific tests or things I should look out for to see if we need to do something else?
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Old 26th November 2020, 08:36 PM   #93
Galu is offline Galu  Scotland
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Quote:
Originally Posted by NewGuy781 View Post
1. ...once I do the new box I just move it al together right? Or is this just a test setup/dry run?

2. Also, what do I look for in the sound as far as to tell if something is wrong? I can think about the obvious like over-powering highs compared to lows ... but is there some specific tests or things I should look out for to see if we need to do something else?
1. I'll let you decide that. Do what you think is practicable.

2. No specific tests are required at this level of refinement, just use your ears!
It's possible that the tweeter will be louder than the woofer, but we'll cross that bridge if we come to it.
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Old 26th November 2020, 08:53 PM   #94
Galu is offline Galu  Scotland
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Quote:
Originally Posted by NewGuy781 View Post
Had to google what was twin flex hahaha (never heard cables being called like that ).
It's a term that's been long used in the UK.

The name 'flex' is short for 'flexible cable' and, of course, 'twin flex' is two core flexible cable as commonly used to wire up speakers.
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Old 27th November 2020, 11:13 AM   #95
NewGuy781 is offline NewGuy781  Italy
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Quote:
Originally Posted by Galu View Post
No specific tests are required at this level of refinement, just use your ears!
It's possible that the tweeter will be louder than the woofer, but we'll cross that bridge if we come to it.

Ok cool! I will be giving this a go this weekend and I will update you


Just a quick last question, provided it all works ok, can I also ask you a couple things about the box build, or should I make a new thread for it?
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Old 27th November 2020, 12:40 PM   #96
Galu is offline Galu  Scotland
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Ask away, but it might be a good idea to do some homework first.

There's lots of information on building speaker enclosures on the interweb e.g. DIY Audio Speaker Box Building Guide

I recommend this book: Designing, Building, and Testing Your Own Speaker System with Projects by David B. Weems (1-Jan-1997) Paperback: Amazon.co.uk: Books A good buy if you can source it locally.

You will find the book to be a valuable source of reference as you progress in your loudspeaker construction hobby.
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Old 27th November 2020, 09:39 PM   #97
PRR is online now PRR  United States
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Help needed to Fix or Repurpose old Speakers
> I recommend this book:

Weems in general is OK, perhaps the best readily-available basic loudspeaker book.

There are *several* titles with more or less in each one. I'd take Galu's suggestion but if it is not readily available take any Weems *speaker* book(*).

While searching I saw some "PDF" copies. The first one I poked-at was clearly NOT going to give me a PDF but maybe an infection.

(*) I did not know this. Weems wrote on goats, high-voltage, and historical fiction: "a young Scottish lord is kidnapped ...to place him in colonial America as a bond servant".
Click the image to open in full size.
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Old 27th November 2020, 09:51 PM   #98
Galu is offline Galu  Scotland
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David B. Weems certainly knew how to 'milk' a profit from his books!

Here's another!


Click the image to open in full size.
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Last edited by Galu; 27th November 2020 at 09:57 PM.
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Old 28th November 2020, 11:07 PM   #99
NewGuy781 is offline NewGuy781  Italy
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Thanks both for the recommendations

Yes, I am reading some articles I have been "collecting" (including your link) and learning a bunch, but there are a couple things that I don't see mentioned and I am wondering if they are "known/proven details" that don't get repeated much or if they are more like a "traditional"/conventionel preference.

So I'm not gonna go all crazy with re-designing, I'm basically gonna recreate with small modification/improvements, since 1 driver is out. Small things like less height and deeper box, and like what you mentioned once: to center the port.

So the question I had was related more to placement or alignment of the drivers on the front baffle. The "traditional" way is top to bottom: high-mid-low-port; or high-low-port. But what if its done high-port-low? Would that be ok, considering that the center of the drivers would be "within the length of a wave at the crossover frequency"? I have also seen some with low-high-port, so I wonder if apart from the distance between speakers and aligning the highs to the listeners ears, does it make a difference?

Also, related to the above and the port, apart from keeping the distance of 1 diameter from the edges of the port to anything else in the box, does placing matter? From what I understand the port kinda acts like a "second" woofer or well an amplifier of certain frequencies (the ones its tuned for), and also I have read that its good practice to raise low freq. drivers like woofers/subs to "even-up" the pressure within the room, "spreading" those freq. more evenly. So given this, would a port-high-low placement be a good idea (or even the previously mentioned low-high port)?

I'm sorry if maybe I just missed this or just have not gotten there yet in my reading, but I cant get this placement question off my head since I haven't seen it anywhere yet*

PS: btw galu, what was the crossover point with these, was it 1500?

Last edited by NewGuy781; 28th November 2020 at 11:10 PM.
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Old 29th November 2020, 01:53 AM   #100
Galu is offline Galu  Scotland
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Actually, there may be good acoustic reasons for having the tweeter and/or port offset. I suggested symmetry simply on the grounds of simplicity and so as not to involve any mathematics!

The actual location of the port is not too critical. I've seen speakers where the port is not at the bottom (see attachment), but I don't fancy it midway between the drivers. I favour the traditional tweeter - woofer - port arrangement. Note also how close the tweeter is to the woofer in the attachment.

The port may be also situated at the rear of the enclosure, which prevents any unwanted higher frequency noises that may emerge from the port from being audible at the listening position.

P.S. There's not a sharp crossover point with this simple arrangement. Rather, the tweeter will roll off very slowly from 6,000Hz and will still be contributing significantly down to 3,000Hz or lower. The tweeter should then blend in with the woofer. I actually changed my suggestion to 3.9uF to go a little lower, but you overlooked that change! No matter, 3.3uF should do, particularly if we have to attenuate the tweeter with a resistor.
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Last edited by Galu; 29th November 2020 at 01:59 AM.
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