Matching Speakers to Amp

[wiresnwood]

Have a Hartke 3500...want to build 2 x 15 cabinet. How do I figure out what wattage the 2 15" speakers should be rated at? Should I just get two 150 watt speakers for peak performance? Will be getting 4 ohm speakers if available.

[GrowlerBox]

Originally Posted by wiresnwood

Have a Hartke 3500...want to build 2 x 15 cabinet. How do I figure out what wattage the 2 15" speakers should be rated at? Should I just get two 150 watt speakers for peak performance? Will be getting 4 ohm speakers if available.

I hope you gotta thick skin, dude, 'cos you about to get yo' ass handed to you.

Bottom line, if you need to be asking this question, you need to be looking at the plans for an established cabinet design built around specific speakers. If you know as little about it as your question implies, you risk making a lot of very expensive and time-consuming mistakes.

Of course, if time and money is no issue, then knock yourself out!

[Sartori]

Two 150 watt speakers... only 300 watts total for a 2x15 cab. The head, if it's the one on their site, says it puts out 350 watts RMS. Not really a problem, but why not get speakers that handle a little bit more power in case you ever want to use a more powerful amp?

Also, if you're going to wire the speakers in parallel, you'll want 8 ohm speakers, not 4 ohm. Two 4 ohm speakers, wired in parallel, will make the impedance of the cab 2 ohms. On the site, it only gives the power rating for 4 ohms and 8 ohms, leading me to believe that 4 ohms is the minimum.

Now, you could wire the cab in series, with two 4 ohm speakers, but that would make the cab 8 ohm. And that would make more sense if you planned on building a second 2x15 in the future.

[wiresnwood]

Thanks Sartori, guess I wrote little too quickly...what I was thinking didn't match my typing. Anyhoo I meant I want to have a 4-ohm load.

re:- GrowlerBox - yes I have thick skin...got that way fighting in two wars. And if I play dumps and dives I don't care about cab specs as long as its loud, I get paid to play. But, none the less, your comments are duly noted. Thank you.

[Bass_Pounder]

For what the materials and raw speakers are going to cost you, it would be much easier (and cheaper) to buy a used 2X15.

There is a heck of alot more to it then throwing a couple of speakers into a box. Without the science and engineering behind it, you could get lucky and have it sound useable - or it could sound like crap, and actually damage the speakers because of improper box size or tuning.

[GrowlerBox]

Originally Posted by wiresnwood

Thanks Sartori, guess I wrote little too quickly...what I was thinking didn't match my typing. Anyhoo I meant I want to have a 4-ohm load.

re:- GrowlerBox - yes I have thick skin...got that way fighting in two wars. And if I play dumps and dives I don't care about cab specs as long as its loud, I get paid to play. But, none the less, your comments are duly noted. Thank you.

That's cool -- it seems that the usual "offenders" are asleep, but if they do start replying, pay attention, because the advice is good. Seems to rub some people up the wrong way, though.

Loud is easier said than done, is at least as hard to achieve as the other specs, and still requires close attention to design.

I think a lot of us get paid to play. Just wish it was enough to justify quitting my day job .

[billfitzmaurice]

Originally Posted by wiresnwood

Have a Hartke 3500...want to build 2 x 15 cabinet. How do I figure out what wattage the 2 15" speakers should be rated at? Should I just get two 150 watt speakers for peak performance? Will be getting 4 ohm speakers if available.

Take GrowlerBox's advice. The wattage rating of the drivers is moot. When you thoroughly understand what everything here means:
Understanding Loudspeaker Data | Eminence Speaker

and using this is second nature:
LinearTeam

then you can think about designing your own cab.

[wiresnwood]

Thank you everyone for your replies. I really do appreciate your advice. I will do my homework. I just thought it would be a fun project to take on and don't want to ruin the speakers or the amp when it's complete.