Balancing speaker capacity with amp

[sliphorn]

Hey all,

I've got a Genz Benz Black Pearl 30w tube amp on the way and I'm gonna use a lopo 1x12 large cab loaded with an Eminence Red Fang 30w 8 ohm speaker.

Eventually I'd like to go with a 2x12 cab for versatility and would like to know if I should use 15w speakers in the 2x12. Seeing as the power will be split between the two speakers it seems to me that two 15w speakers would be optimum. Yes? No? I realize that even a low power amp can drive a high watt speaker, but when does it get to the point where there's not enough power for the speaker to be all that it can be?

If I really love the sound of the Red Fang I'd consider using two of them for the 2x12, but they're available only as 30w. I know the 30w amp would easily drive the pair but would I be getting the most out of them?

Also, any preference for wiring a 2x12 in series or parallel? Hope I didn't open a can of worms with that one.

Thanks....................

sliphorn

[In The Light]

Hi, Sliphorn. Well since your amp is 30 watts, only 30 watts total of speaker wattage capacity is risky, and may not even sound best, as speaker distortion onset will happen relatively fast with a speaker rated the same wattage as the amp, especially is you have a tendancy to really crank your amp, like I do. Yet, many vintage amps were indeed designed as such, with equal rated amp and speaker wattage, and it can sound great, bluesy and intense.

Some speaker distortion can be a good thing, but you might have a bit too much speaker movement happening. I always recommend keeping speaker wattage handling at 150% - 200% of an amps RMS wattage rating. This is especially important considering the fact that most amps are rated RMS wattage, so an amp rated 30 watts RMS can easily approach 40 watts or more under full volume/distortion. This is true with many amps - for instance, many vintage Marshalls, though rated at 100 watts would acheived 180 watts at full volume! So, be careful.

Two 15 watt speakers is essentially the same concept as a single 30 watt speaker - I would not go that route. Even though Vox did in the day - the 30-35 watt Vox "Top Boost" contained two 15 watt speakers, but they often blew. So, I'd personally recommend two 20-30 watt speakers or one 40-60 watt speaker. This will give you a more controlled speaker distortion and tone - it will sound tighter and have plenty of transients and response.

As far as worrying about not having enough power to drive a speaker, that is never really a significant issue in theory, as you could theoretically drive a 100+ watt speaker with your 30 watt amp with no problem at all. However, issues you would incurr are things like a lack of good transient response and speaker interaction, as the surround of the speaker is quite stiff at that high-wattage, so tone would be effected and might not be to your liking. But, it's completely safe to do, and many jazz and metal players do just this. But for Rock, Blues and most genres, I would stick to my 150% - 200% parameter for best tone (though you can indeed go with an equal 100% rating and get great tone - it's just you have to keep the issues previously explained in mind). Also, interestingly you would get less volume with a high wattage speaker (stiffer surround and cone) as you would with say a 30 - 40 watt speaker, given all other factor are equal - like SPL. This is because lower wattage speaker have looser surrounds and quicker response, so they will have more movement (and thus more volume) at the same input level.

And, SPL is what ultimately indicates the speakers perceived loudness - the higher the SPL, the more volume you will get. 96 - 98 SPL is considered low SPL and 100+ SPL is considered very efficient. This doesn't mean better sounding mind you - just more efficient and louder.

Lastly, regarding wiring, I recommend parallel wiring - as it's safest and fullest sounding as well.
Hope this helps...

-Mike

[sliphorn]

Mike, thanks a lot for the excellent information. It definitely helps me in my future speaker decision making.

The reason I chose the 30w Red Fang was based on the fact that Genz Benz uses it in both their 1x12 and 2x12 Black Pearl combos. I'm not the type to crank it all the way up anyway, so I'm sure it'll be cool. Thanks again..........

[In The Light]

Glad to help, Sliphorn.