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So, how many watts are my speakers?

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#1
Hi, I got some old speakers that sounds really good and I need to buy an Amp.
The problem is that I don't know how many watts the speakers are.
We're talking about 2 speakers, each with:
1. woofer: Philips AD8061/W8
2. tweeter: Philips AD0161/T8
3. mid-range: MEROT 5030S, 8 ohms, 20 W

For the first two I found an old Philips catalog (attached, and I highlighted what matters).
In the catalog it is very clear that the tweeter and the woofer are 8 ohms, but I couldn't understand how many watts.
For the mid-range I couldn't find a thing, but it's written on it 8 ohm, 20 W.

So, how many watts are my speakers?
Is there a specific number or is it a range?
And how much watt amp do I need to buy?

Thank you,
Gal.
 

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Xulonn

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#2
The above pdf is from 1978, and lists the midrange driverss as "Squawkers"! I haven't heard that term for a midrange driver in decades!

4 watt power handling capacity for the tweeter? Is that common?
 
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solderdude

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#3
Suited for amplifiers between 15W and 50W !
Not a problem to connect it to say a 100W amp or so... just don't give parties in that case.
Wouldn't use them with less than 15W rated amplifiers. It is easy to destroy your tweeters that way.

When you hear distortion you have to dial back.
 
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Juhazi

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#4
Any hifi or AV receiver/amplifier will do. Loudspeaker drivers wattage is quite irrelevant for home hifi.

But you must measure them and create/desing a crossover and a box for them. Without crossover you can easily burn the voicecoil or break the suspension of the midrange and the tweeter, by sending low frequencies to them.

So, please start studying how to design a multiway loudspeaker! Websites worth reading eq.
http://speakerdesignworks.com/index_page_3.html
http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm#PAGE_INDEX scroll down to the bottom of the page!
http://www.zaphaudio.com/mantras.html
http://www.mh-audio.nl/
http://linkwitzlab.com/frontiers.htm
 

solderdude

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#5
I suspect he has an old speaker with an XO filter in it. Don't think he plans to build something with those drivers.
He is just wondering what power levels were needed and probably took out the drivers to have a look ?

For building your own speakers the links are excellent starting points (and beyond)
 

Juhazi

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#6
Oh, if it is a ready-made speaker, it has some kind of crossover. The problem with that old speakers is that the tweeter has too shallow xo slope and it is quite easy to burn it's voice coil with too high spl/watts. Or to blow the woofer if the box is ported.

3-way speakers often have quite high sensitivity, so an ampifier with 20-100W per channel is ok. Obviously the speaker is rated to have 8 ohm inductance, so that is easy for any ampllifier too. 20W is enough to break the speakers, so be careful with spl! An amplifier with say 300W per channel is okay too, but because of it's higher gain there might be some hiss or hum at low spl volume.
 
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#7
Thank's!
That's right, I just took them out to take a look.
What are the differences between "power handling capacity" and "operating power" ?
So the woofer is 30W, mid is 20W and the tweeter is approximately 10W. ---> 30+20+10 = 60W ?
Or only the woofer is determine the speaker wattage? so 30W?
I'll check about the crossover, if there is one..... :facepalm:
 

solderdude

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#8
There will be a crossover with 100% certainty, otherwise your tweeter would already have been toasted and the speaker would have had an impedance of 2.5 Ohm instead of 8.
It will be a simple one most likely

The woofer can handle a continuous sinewave of 30W for a specified time period (can be indefinitely).
The midrange (squawker) can handle a 20W continuous ? (I can't find any info on it)
The tweeter can handle 4W continuous.

The woofer dissipates the biggest amount of power as most energy is concentrated below 300Hz or so, the tweeter will only receive the highest frequencies which are a lot lower in amplitude (averaged) so the power handling capacity can be far less.

So it isn't a matter of adding it up.

A 30W continuous power will generate about the same amount of heat as music content with an average power of 30W.
In such a 30W average power music signal there can easily be (short) 100W peaks.
The tweeter as well can handle 15W peaks as long as they are short duration.

So the power handling capacity of the whole speaker will be between 30W and 100W (roughly) while the operating power will be between 0.1W and 1W while playing music at a normal level.
 
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#9
Ok,
I still don't understand the 30-100 range.
Is that means that the minimum amp wattage I need is 30W and maximum 100W?
Isn't it a big range? What will be optimal?

And another thing.
The box is totally ruined so I had to take everything out.
I will place them in another box I have (same size..).
I know it looks terrible, but the sound is good.
So I guess no crossover after all?

IMG-20190330-WA0009.jpg
 

Juhazi

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#10
Oh my good, there are just serial capacitors for mid and tweeter. No coil for the bass. Minimal built-in enclosure for the mid. Total garbage.

About that wattage, amplifiers "power rating" means their maximal continuous or peak power output to certain load, typically 4 ohms.. Even the most efficent integrated amplifier in the world has a knob to turn down output level/voltage. Just don't turn it up to 10 on first try and speakers will be fine.

https://www.themasterswitch.com/how-to-match-speakers-and-amps
 

solderdude

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#11
Ok,
I still don't understand the 30-100 range.
Is that means that the minimum amp wattage I need is 30W and maximum 100W?
Isn't it a big range? What will be optimal?
No it's not a big range.
30W is only twice as loud as 3W
The difference between 30W and 100W is merely 5dB

As stated in my first reply:
Suited for amplifiers between 15W and 50W
That's your optimal range but 60W, 75W or 100W amplifier is not a real problem, just don't play it very loud.

And another thing.

So I guess no crossover after all?
You guessed wrong. There are 2 (bi-polar) electrolytic caps that function as a high pass filter.
The woofer gets full range and drops off naturally above 4 kHz.

The midrange is high passed (6dB/octave) probably at around 3kHz.
The tweeter is high passed at an even higher frequency maybe even 7kHz.

The XO is the simplest (and poorest) one can find.
As Juhazi already said there are no low pass filters so the crappiest filter around but a filter none-the-less.

When you give us the values of the 2 capacitors (the grey and black 'cans' near the midrange and tweeter) we can calculate from which frequency upwards they mid and tweeter do something.
 
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#12
It's bad, I know...... :facepalm:
I have one or two crossovers from other speakers(I can upload a photo tomorrow), but I don't know their condition and if they can fit these elements. how can I tell?
these are the capacitors:
mid.jpg tweeter.jpg

Now I'm confused, should I try and connect the crossovers? is it fine like that? change capacitors? throw it away??
really appreciate your time, Thank You both!
 

Juhazi

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#13
Solderdude is better in calculating highpass with those caps. (but we don't know inductance curves of mid and tweeter) if your friend has extra 5$ to use, change them to new ones with similar values.

Switching to some other speakers crossover circuit just makes things even worse! Keep it as is or throw to recycle bin! Actually those paper/polycone drivers are pretty good for minimal xo.

The effort to measure their response and inductance to create a modern well done crossover circuit is only worth as a learning process.
 

solderdude

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#14
2kHz for the midrange (maybe a tad lower) and about 4kHz for the tweeter.
The filter for the tweeter is on the low side and would put in 2.2uF myself.
I reckon you can even remove the midrange and still get about the same sound as the tweeter comes in where the woofer drops of by itself.
The woofer won't do very well there so maybe that's why they added the midrange.

I would not worry too much about it.
Slap some wood around it, lightly fill it with some damping material and call it a day.
You would have to know more about the midrange to design a proper filter for it.
 
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#15
Ok, I did a lot of reading about fitting the right capacitors and crossovers, but with lack of information for the midrange I decided just to replace the old capacitors (and cables) to new ones and finish it.
I think it will be good enough for a while.
Btw, reading the specs of the woofer and tweeter it really seems like the mid doesn't have to be there, and I guess it's like you said, to support the woofer in the drop. the woofer has a big range 30Hz-5000Hz.

Thank you very much for everything! :)
 
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