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Permalink Reply by Ron "Oily" Sprague on August 28, 2015 at 5:15pm

You could get away with the 16, but your Hifi won't fully drive it, although it will come close. Better choice would be an 8 ohm speaker.

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Permalink Reply by Bufo Bill on August 29, 2015 at 1:23am

Thanks for the help, I wonder if you could clarify a few things? Will the under driven speaker just be quiet, or will it affect the sound quality as opposed to the db level? I heard that driving an ill matched speaker can fry the transistor circuit, do you think this speaker would do that to my amp long term?

I am in the UK and am having difficulty finding an 8 ohm 15 Watt speaker in a 12 inch size, this is why I am not just going with your verdict from the get go, Ron, I am not questioning your judgement.
Many thanks from Bill. :D

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Permalink Reply by Bufo Bill on August 30, 2015 at 7:07am

Found a more suitable 8 ohm speaker, but I would be interested to hear any responses to my questions in the previous post.
All the best from Bill. :D

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Permalink Reply by Ron "Oily" Sprague on September 1, 2015 at 9:55am

Bill,
Sorry, been busy the last couple days. Yes, it can be tough to find an 8 Ohm, 15 watt, 12" speaker. An underdriven speaker can sound just Ok at lower volumes, but you won't get the proper tone from it if the amp has to put too much power into trying to overcome the impedance mismatch. It will affect both sound quality, and perceived volume. You could potentially fry the circuitry with an impedance mismatch, but only, say if you were using an amp rated for gobs of power, designed to go through, say, a 16 ohm speaker at, say 50 watts, and instead hooking up a 4 ohm speaker rated for 5 or 10 watts. You'd fry the speaker an possibly damages the amp as well. Interestingly, if you get the wattage close, you can sometimes get away with using a lower impedance speaker, say substituting an 8 for a 16 ohm, but even then, that 8-ohm speaker will never sound as good as one properly impedance matched.

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Permalink Reply by Bufo Bill on September 1, 2015 at 10:37am

Hi Ron, thanks for responding again. Thanks also for the info, that's just what I wanted to know, and very succinctly put too, the amount of posts on electrics that I read through and need to google . . . but I am slowly learning, with help from folks like you.
Just for the record, I went for a 12 inch 8 ohm speaker rated at thirty watts, and I'm going to build another for a friend with the 16 ohm.
Once again, thanks Ron.
All the best from Bill. :D

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