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I have a set of c5 _ 1 compact mordaunt short book shelf speakers and  I would like to know what wattag they are if anyone has a idea it only says impedance  80 hm any help would be great thanks as trying to sell them and keep getting asked for wattag but people won't go for they sound great they want the wattag lol

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Don’t they have a nominated number of ohms on the plate?
The lower the number usually indicates ‘the harder to drive’ so you need more power feeding into low ohms speakers to drive them properly.

As I understand it 4ohms  Speakers are ‘less efficient‘ than 8ohms by a fair margin.  

Nominating a wattage limit for a passive speaker is a bit strange to me as wattage is generally a unit of electricity.
Definition: The watt is a unit of power. In the International System of Units it is defined as a derived unit of 1 joule per second, and is used to quantify the rate of energy transfer. 

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Do you mean the cs1 sold as a surround speaker--but with good sound?

 

Frequency response : 80Hz - 20kHz
Sensitivity : 87dB
Power rating : 10 - 100watts
Enclosure : Mica loaded polymer
Impedance : 8 Ohms
Dimensions : 160mm x 233mm x 131mm

MordauntShortCS1_zps3717cac2.jpg.6a74f3e173e93dd34dbc926d9be863c1.jpg

dsc_1619.jpg

Edited by doogie44
better photo
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Your speakers themselves are zero watts. Perhaps if you push the driver in and out you may even get up to 1 watt out of the binding posts.

 

All the speaker manufacturer is saying is “an amp outputting 10-80 watts should run these” - but it’s largely bollocks, knowing people would be wary if there wasn’t a wattage rating.

 

A ten watt amp clipping can blow tweeters in seconds, a 1000 watt amp outputting 50 watts will be outstanding.

 

Power ratings on speakers are about as useful as putting Kw ratings on tyres.

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On 02/10/2020 at 3:18 AM, Alan Goodman said:

I have a set of c5 _ 1 compact mordaunt short book shelf speakers and  I would like to know what wattag they are if anyone has a idea it only says impedance  80 hm any help would be great thanks as trying to sell them and keep getting asked for wattag but people won't go for they sound great they want the wattag lol

Watts 100 they are. Ohms 8 are they also.

 

Pleas econsider going somewhere else next time you want information - like doing a quick search on the internet.

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3 hours ago, Cloth Ears said:

Pleas econsider going somewhere else next time you want information - like doing a quick search on the internet.

but 80 "hms" and wattag was entertaining...well done @doogie44 for deciphering ?

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55 minutes ago, almikel said:

but 80 "hms" and wattag was entertaining...well done @doogie44 for deciphering ?

My speakers used to 'hm', but I taught them words and they're fine now!

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19 minutes ago, Cloth Ears said:

My speakers used to 'hm', but I taught them words and they're fine now!

my speakers used to hm, but I tracked down the earth loop...but singing in a rock covers band, when I forget the words a few hm's, yeah's, mmmm's, and repeating the 1st verse gets me through... :)

It's amazing how you've sung a song many 100s of times and your mind goes completely blank about to start the next verse...it's quite disconcerting in front of a big crowd  :(

 

Mike

 

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On 03/10/2020 at 3:46 PM, Tony Martello said:

As I understand it 4ohms  Speakers are ‘less efficient‘ than 8ohms by a fair margin.

completely off topic but the OP's question was answered....

 

Hi Tony,

A speaker's nominal impedance (eg typically 4, 6 or 8 ohms) doesn't relate directly to a speaker's sensitivity (ie SPL at 1W/1m).

Plenty of 4 ohm drivers have a higher sensitivity than different 8 ohm drivers, and some drivers that are available in both 4 ohm and 8 ohm versions have the same sensitivity/SPL at 1W eg the drivers I use for mid bass http://aespeakers.com/shop/td/td18h/

 

When you connect an amp that has a low output impedance (all typical modern solid state amps, which try to be constant voltage sources) to the 8 ohm and 4 ohm driver versions of the TD18s above, the amp will try to keep the voltage the same, but as the impedance of the 4 ohm version is lower, the amp pushes more current, and delivers more power (approx double), and SPL (expected as you're delivering more power from the amp).

To measure the sensitivity of 2 drivers of 8 ohm and 4 ohm respectively, you would have to dial down the volume knob for the lower impedance driver, so the amp was delivering the same power to each - which can be seen in the sensitivity specs of the TD18 for the 4 ohm and 8 ohm versions - the same 98 dB@1W/1m.

 

For this reason some driver manufacturers specify their sensitivity @2.83 V rather than power...it's much easier to get an rms voltage reading across the input of a driver compared to an input power measurement (which needs to be calculated from any 2 of voltage, current, driver impedance).

In the example of the TD18s, @2.83V at the speaker terminals, the 8 ohm has an SPL of 99.7dB, and the 4 ohm has an SPL of 102.7dB - a 3dB SPL increase. This is expected as 2 x the power is going into the 4 ohm version (P=VxI, V=IxR etc).

 

cheers

Mike

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On 04/10/2020 at 12:17 PM, Billy Shears said:

Power ratings on speakers are about as useful as putting Kw ratings on tyres.

it's a guide, and IMHO power ratings on speakers are generally useful to give consumers some idea about matching amps and speakers.

 

I would typically suggest to purchase amps and speakers in similar capabilities, but it's fine for the amp to be capable of a bit more...but use your ears, eyes and nose to identify system stress.

Obviously hearing distortion and seeing over excursion of drivers means turn your system down!...

...but smell is a very under-rated sense in detecting hi-fi stress - amps have a smell when they work hard, drivers also when the glue in the voice coil is about to fail :(

On 04/10/2020 at 12:17 PM, Billy Shears said:

A ten watt amp clipping can blow tweeters in seconds, a 1000 watt amp outputting 50 watts will be outstanding.

Clipping amps do generate higher harmonics, which end up needing to be managed by the tweeter, but that's not what blows tweeters up when amps clip - it's much more about what power is delivered to the tweeters, and that the power delivered to the tweeter goes up under clipping (power compression of the amp), with only a small amount of this additional power being due to the harmonics of the clipping.

 

A speaker designed for say 500W, with a tweeter capable of managing say 25W, is unlikely to be damaged by a 10W amp regardless of how much it clips...and it will sound so terrible when clipping hard, any sympathetic listener will turn it down!

 

On the other hand it's very easy to wind up the 1000W amp in your example from 50 watts to well beyond what a 100W speaker could manage - both woofer and tweeter would have melted voicecoils very quickly...parties with inebriated patrons in possession of the volume control will mean toasted voicecoils for breakfast...

...been there...and also have had plenty of toasted tweeters through no amp clipping but trying to push the crossover too low/loud on active setups.

 

I think power ratings on speakers and drivers are very useful as a starting guide, but from there, if you choose to push your kit (as I do all the time), a sympathetic ear/eye/nose goes a long way to not breaking stuff.

 

cheers

Mike

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On 04/10/2020 at 1:17 PM, Billy Shears said:

Power ratings on speakers are about as useful as putting Kw ratings on tyres.

 

Tyres do have speed ratings though - and much like power ratings for speakers, these have consideration for the physical/thermal capacities of the tyres. 

 

Power ratings on speakers do matter, if the manufacturer has specified them properly. However, they are grossly misunderstood by the majority of people, as you've outlined in your post. :)

 

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1 minute ago, pwstereo said:

That's PJ Harvey.

I saw her at a Big Day Out many years ago - she rocked! cool guitar also. 

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12 hours ago, almikel said:

I saw her at a Big Day Out many years ago - she rocked! cool guitar also. 

Polly Jean has an interesting dress sense - which means I have to be careful about which pictures I choose as my avatar. At least two have fallen foul of the 'taste police' (not, in any way, an indictment, Marc!) - one also with the Gibson and another with the 'Lick My Legs' tshirt (and little else). I'll admit to not being a total fan, but some of her stuff sends chills up my spine, even after the 100th listen.

 

We should get back on topic, just in case Mr Goodman wants to post a second time.

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