Another old Pioneer SX-434 question-speakers

Thanks to all those who replied to my last questions about my old SX-434. I have done everything advised except actually powering it up. I have decided to power it up slowly by using my nice isolated output Staco variable transformer. I do not as yet have speakers for the thing and will be looking for some used ones. Besides being 8 ohms what should I look for? I have always bought speakers and amps at the same time, listening to them before buying. But since the SX-434 is going into my shop, and may not work when power is finally applied, I'm not too keen on buying new speakers. At least not yet. This amp has a 15 watt output. Besides listening what else should I look for when buying speakers? My plan is to power the thing up with speakers from another stereo just to see if it works. Then I'll be off to the local thrift stores to see what they have to offer. And I'll bring the SX-434 along to test the speakers. But it has been so long since I bought speakers I don't remember what to look for. Is there any easy way to test the efficiency of the speakers? Any brands to look for? These speakers will be hanging from a plywood wall about 12 feet up in my machine shop. I really don't care about the size because they will be totally out of the way. Thanks, Eric

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etpm
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The two most obvious points are that the speakers be rated to handle 15 watts, and that they be either 4 or 8 ohms. (The SX-434 can handle either.)

15 watts is a fairly modest speaker rating, but it's above the usual "computer speakers". Any ordinary "bookshelf speaker" will be probably fine. All are either 4 or 8 ohms.

To test efficiency (in the sense you mean), you'd need some sort of calibrated source material, plus a way to measure the output level. For your purposes, just listening should be OK for the latter. For a "calibrated" source, bring a portable CD player and use a piece of tape on its volume control so it doesn't get changed. On the SX-434, note the volume position and keep it the same for all tests.

However, I think that efficiency is probably not what you should be shooting for. Instead, go for decent frequency response. You can tell that by listening to your CD, and picking the speakers that sound best to your ears. As a general rule of thumb, smaller speakers will have reduced bass response. But bigger isn't automatically better: A poorly-designed big box can sound boomy, for example. That's why you have to listen for yourself.

You can enhance the bass in your shop by hanging the speakers near the corners. A 3-way room corner gives the biggest effect, followed by a 2-way (wall-ceiling or wall-wall).

Best regards,

Bob Masta DAQARTA v7.50 Data AcQuisition And Real-Time Analysis

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Scope, Spectrum, Spectrogram, Sound Level Meter Frequency Counter, Pitch Track, Pitch-to-MIDI FREE Signal Generator, DaqMusiq generator Science with your sound card!

Reply to
Bob Masta

Thanks for the reply Bob. As it turns out I can get close to then three way corner you suggest. So I'll mount the speakers there first and see how they sound. I guess I'll test the SX-434 first on low volume with some computer speakers and if it works then I'll lug it and an MP3 player to the thrift store and try some speakers. Eric

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Reply to
etpm

I forgot to mention one important detail when looking for used speakers: Back around 1980 or so they started using foam surrounds on the woofers. (The surround is that flexible ring between the moving cone and the rigid frame.) Used to be just accordion pleats in the paper cone, or treated fabric, or butyl rubber, etc. But the foam was very light and flexible (and probably very cheap as well), so it must have seemed perfect for this job. The only problem is that the foam breaks down over time, until it totally disintegrates. (You may have seen this on old foam ear cushions on headphones, for example.)

Dunno when they stopped using this stuff, or even if some speakers are still being made with it, but it is Bad News.

So, if you can remove the grille without damaging anything, take a look at the surround. Wipe your finger lightly around it and see if it is falling apart. Many grilles are just held in by Velcro or snaps, or press-fit into a molding around the front face of the enclosure.

Other than visual inspection, you'll probably know if the surround is totally deteriorated since the speaker will make horrible knocking and grating sounds on low bass notes. It's the just-shy-of-dying speakers that you need to watch out for. Hopefully, those foam surround speakers are long gone by now, but it doesn't hurt to check.

(Places like Parts Express sell kits to replace the surround, but it involves nerve-wracking major surgery... not worth it in most cases.)

Best regards,

Bob Masta DAQARTA v7.50 Data AcQuisition And Real-Time Analysis

formatting link
Scope, Spectrum, Spectrogram, Sound Level Meter Frequency Counter, Pitch Track, Pitch-to-MIDI FREE Signal Generator, DaqMusiq generator Science with your sound card!

Reply to
Bob Masta

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