26 replies to this topic

[shiny_car]

The gear is all awesome. Of course, ebay poses various risks, so just be prepared to accept them (eg: fakes, refurbs, no local warranty, etc), but you can save some money for sure.

[Semes]

shiny_car, on 15 January 2012 - 08:38 AM, said:

no local warranty

I can buy it twice from Ebay before I even get one local

[shiny_car]

You might need to!

[Semes]

Am I going to be able to run the SPZ60 off a Pioneer AVH-P3350BT without the use of an amp?

Edit: Is it going to be bad if I under power it?

Edited by Semes, 21 January 2012 - 04:09 PM.

[shiny_car]

To underpower means they won't be as loud as they possible could. Not necessarily a bad thing.

The SPZ are 3ohm speakers, and the HU is designed to run nothing lower than 4ohm speakers. It will probably work, up to a certain volume, before the risk of the Pioneer overheating and/or shutting down. So it could prove unreliable.

Not to mention it's a total waste of the potential of the Bostons. Only a proper amp will provide the proper hard-hitting dynamics, frequency response, and clarity. For a temporary measure, until you fit an amp, fair enough, you might consider running off the Pioneer. But because they are 3ohm, the HU may not like it.

[Semes]

shiny_car, on 21 January 2012 - 06:46 PM, said:

The SPZ are 3ohm speakers

Can any amp be made to run at 3ohm? Because all of there amps only list 2 and 4ohm.

Thanks for all the help.

[shiny_car]

Yes. Thing is, you don't 'set' the amp to operate at a particular ohm; it just does it depending upon the speakers. The ohm (impedence) does determine how much power the amplifier produces though.

If you wonder why speakers aren't just 2ohm, to have the amp produce more power, it's a compromise. Usually, an amplifier operating at 4ohm produces enough power for speakers without needing to have 2ohm speakers. At 4ohm, there is lower distortion from the amp, and lower power consumption.

To estimate the power the amp might produce with 3ohm speakers, it will be approximately midway between the 2ohm and 4ohm specs.

[Semes]

shiny_car, on 22 January 2012 - 03:18 PM, said:

To estimate the power the amp might produce with 3ohm speakers, it will be approximately midway between the 2ohm and 4ohm specs.

In that case I'm thinking the GT-2125 would be the best choice?

4ohm: 125 Watts x 2
and
2ohm: 200 Watts x 2

So I'm guessing it would be around 150 watts at 3ohm.

Do I need to factor in the tweeters to this equation too? Or on there site when it says 150watts is that already including the speakers?

[shiny_car]

The Boston GT amps are very good, so would be a good choice for the SPZs. 150WRMS at full power is probably about right, at 3ohm.

The power handling of the speakers is for the 'set', with the passive crossovers. The tweeter - without the passive xovers - would have quite low power handling, say 50WRMS. One function of the xovers is to attenuate the power (ie: reduce the power reaching the tweeter), not only to avoid overpowering them, but because they don't need as much power as the woofers to go loudly.

[Semes]

shiny_car, on 23 January 2012 - 10:56 AM, said:

'set'

One last question then I'll stop annoying you

Do I want 75 Watts x 2 or 150 watts x2 you said 150w for the set, so I'm assuming I would need 75 watts each side and that 75w x2 means each side is getting 75w?

[shiny_car]

Haha, it's ok. Good to ask questions.

By 'set' I was referring to 'one side': woofer + tweeter + xovers. As such, a 2x150WRMS is what you probably want.

[Semes]

shiny_car, on 23 January 2012 - 12:29 PM, said:

Haha, it's ok. Good to ask questions.

By 'set' I was referring to 'one side': woofer + tweeter + xovers. As such, a 2x150WRMS is what you probably want.

Cheers, yeah I want to go into the shop knowing exactly what I need. That way if they try to pull a sheet over my head and sell me stuff that I don't need I can look else where.