2 amps, 1 cab, your thoughts?

Liberate247 · #1 January 10th, 2008

I have an idea that I would really like to have come to life. I've been playing guitar for about 7 years now and Metal is what I love to play the most. What I was thinking is having 2 heads, one solid-state and one Tube. I currently have a tube Randall RGT 100. I would be adding a pretty heavy sounding solid state amp, however I have yet to decide on one. I would like to pick one up for $500-$600. So if you have any suggestions let me know!

I would be using 2x12 400w Eminence speakers per head in one 4x12 cabinet. Also, I will be using an A-B-Y selector box to run my guitar to both heads so they can run Simultaneously. 2 amps, one solid state, one tube, same time. How could I go wrong? I would think the sound would be so huge it would melt faces. Your thoughts?

fly135 · #2 January 10th, 2008

Just make sure that your pairs of speakers are wired to separate jacks and isolated. Don't tie the output of your amps together by plugging into a daisy chained output jack.

Liberate247 · #3 January 10th, 2008

I know, I've got 2 input jacks on the back of my cabinet so I can have two of the speakers per head, but do you think having 2 seperate amps going thru one cab is going to distort the sound? The two sounds aren't going to be seperated into different cabinets so I hope the tone from one amp doesn't effect the tone from the other since the speakers are going to be so close together.

fly135 · #4 January 10th, 2008

All you can do is try it. Another consideration is polarity. If the sound is thin try swapping the polarity of one set of speakers to make sure the bass isn't canceling out.

Liberate247 · #5 January 10th, 2008

awesome, thanks for the advice. Any recommendations on a good Solid-state head to mesh my Tube sound with? I was looking at the Fender Metalhead amp, but thats a little pricy and 500w for a solid-state head? Sounds like overkill, but I've heard nothing but good things about it.

P-90 · #6 January 10th, 2008

Quote:

Originally Posted by Liberate247

I was looking at the Fender Metalhead amp, but thats a little pricy and 500w for a solid-state head? Sounds like overkill, but I've heard nothing but good things about it.

I typically use speakers that are rated at double what I intend to put through them, and never more than maybe 40 watts through a 12", if that. I realize that some may be rated at hundreds of watts each, but have you ever tried it? The rating may assure you that your voice coil won't melt when hit with 200 watts at 1 KHz, but the same 200 watts at the fundamental frequency of low E (80 Hz) would send that voice coil flying right across the room. It has to move literally 100 times as far to produce the same acoustical energy at 80 Hz as at 1000, and, since no cone can move a few inches forwards and backwards, the only way to deal with that is more cone surface area. Half a dozen 15s might be happy with 500 watts, but two 12s? Naah.

So my only thought would be: what good is 250 watts per speaker going to do you?

Liberate247 · #7 January 10th, 2008

The 400w Eminence speakers should be able to handle the 500w metalhead amp. 2x 400w =800w handling for a 500w load, should be alright as long as I'm not cranking it to 11. Guitarists who use HUGE amounts of wattage thru their speakers aka. Zakk Wylde, have at least 200w per speaker. Also, all Eminence speakers are tested for like 9-12 hours with the same amount of wattage handling the speaker is designed for. so.. 400w speakers get 9-12 hours of continuous 400watts of power.

P-90 · #8 January 10th, 2008

Let me bore you with a little math to clarify what I meant.

I'll start by defining an acoustical watt; this is the amount of sound your speaker would make with 1 watt of input, if it were 100% efficient. A typical guitar speaker is between 2-3% efficiency, so expect it to take 30-50 watts of amp power to make one acoustical watt.

For a 12" speaker to make one acoustical watt at 1000 Hz, the cone has to be able to move forwards and backwards about 1/200th of an inch. Does this sound challenging? Not at all. To produce one acoustical watt at 80 Hz, it has to be able to move forward and backwards by over half an inch. This is not just challenging, it is impossible without breaking the speaker; to take a look at the Eminence Tonker (12", 150 watts, 300 watts peak), for example, its maximum cone excursion ("Xmax") is 0.8 millimeters, or about 1/32 of an inch. So it would be physically impossible for that speaker to produce over 1/16 of an acoustical watt at 80 Hz without bottoming out or breaking.

At 3% efficiency, 250 watts would translate to 7.5 acoustical watts per speaker. To produce that level at 80 Hz, the cones would need to be moving forwards and backwards by almost 4 inches!

So that's the problem, you see. It may be a 400 watt speaker at 1 KHz, but at the fundamental frequency of low E, no 12" guitar speaker can handle much more than 10 or 15 watts. The cones just can't move that far.