16 replies to this topic

[mayday]

I just picked up a set of boston acoustics spz60. I bought em off eBay an since I haven't got the rest of my system yet I wanted to make sure they work. Is there a way I can test them safely to ensure they work ok?? I only have a home theatre amp unfortunately.

[Big_Valven]

Basic test consists of a AA battery and some scraps of wire. Touch it to the midbass, with the polarity correct, and the midbass cone will move outwards without any scraping or bad noises.
Same for the tweeter - it will 'crackle.'

Only do this momentarily - ie no longer than one second.

Most home theatre amps are capable of running 4 ohm loads but since the SPZs are 3 ohm, I wouldn't risk it.

Edited by Big_Valven, 22 December 2011 - 02:05 PM.

[Damon]

Don;t worry abou the nominal 3ohm impedance. The home theater amplifier will happliy run the speakers for a quick test.

[mayday]

Is it just long term when damage can be done using home amplifier?

It is a Cambridge audio amp, it was around $2000 new so it's fairly decent. So you think Internals should be able to cope with a 30 second test?

[268669♫]

if you keep the volume down it will be fine. If your really worried and you just want to check that the speakers work, connect both up in series for a 6 ohm load on just one channel. The amp will happily run that.

[Big_Valven]

^what he said

[ubernoob]

Just remember to use the crossover as you would in the car, you don't want to feed the tweeter full range signal.

[mayday]

Thankyou very much I'll give it a try. I just remembered I have a mini Hifi in my bedroom so I'll use that so at least if it does break it ain't so expensive

[Damon]

Don't fret of the impedance load thing. It is actually more about exceeding the current capability of the amplifier's power supply than the amplifier 'seeing' a low impedance. At a couple of watts of output the current flow capabilities of any amplifier will be no problem whatsoever for a 3ohm load.

Its a non issue.

[mayday]

Ok, but im coming after you if it breaks! Jokes:)

Thanks for help

[KGB]

I agree with Damon - the impedence "issue" is about allowing too much current to flow (due to low resistance) and the amp cooking itself. For a short test at low volumes it really is a non-issue. Apart from that, most decent amps will shut down or go into "protect" mode before anything bad happens anyway.

Did you test it and find out?

[mayday]

Thanks everyone, yes connected it up and they ran fine. I didn't turn them up loud just enough to make sure they worked. I'm dying to get it all installed.

I picked up an alpine pdx6 amp which I will bridge two rear channels for a sub.

Out of curiosity would you recommend a g2 (300 rms)or g3 (375rms)Boston sub? Bridging will produce 300rms. The g3 will be a bit underpowered. Although the birth sheet for amp has 174watts so maybe 348watts is produced?? Is 300 enough to run a 375w sub?? My main concern is the g2 won't keep up with the spz60's??

I don't want obnoxious loud, just quality sound which I can turn up at good volumes.
Also iDon't want two amps

Btw I really appreciate the honest unbiased views of this forum, inexpected a car audio forum full of know it alls with show off attitude. It's good to see a mature attitude on here!

[DrBoom]

• which ever amp you decide to use for the component speakers, the general rule as indicated by David Navone of autosound 2000 magazine is the ratio of 2:1 so for 100watt high pass amp, you would need a 200rms amp for subwoofer duties, Another important factor to consider is the use of one or more subwoofer as every additional subwoofer will give you a 3db gain, which most newbies like but over time as you learn to appreciate sound, a single subwoofer which blends in with the front stage is an ideal concept most SQ buffs would like to achieve ( including me!)

Good luck mate, you will find that 150rms would be more than efficient to run them Bostons!

[mayday]

Definitely only want one sub! I don't want huge loud bass, just clean tidy sound. I've decided to get a boston g3 sub now. From everything I've read they seam to be very good sq. (my ears are always goin to be the best judge) but the small box required for it is a huge bonus. I've done some measuring and I'm forced to go with a 10" as it requires only 0.5ft box. I can't fit much bigger in the required space.

Thanks for the help

[KGB]

Go and read the "setting the gains" tutorial. Running a 300W amp to a sub thats rated to 375W is fine. The 375W is a nominal figure from the manufacturer and is a recommendation for the max safe power handling. "Underpowering" is not a problem - how much power do you think the sub gets when you turn the volume down?
Its all about the gains.