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Run a Spider IV 75 with a 2 x 16ohm speaker cab?
by westicle1986 on 2011-12-12 16:51:47.1240

Hey all,

I have the Spider IV 75 watt 1x12 combo. It currently has the 12" 8ohm speaker.

If I was going to build a parallel cabinet with 2 x 16ohm speakers, could I hook them up to the speaker wires of the Spider IV 75?

I know the Spider has 8ohm setup for the single 12" speaker, but would there be any other variables I need to think about? Wattage differences? I'm still kind of a noob at this haha


1) unhook the 12" 8ohm in the spider iv 75

2) hook up cab with 2 x 16ohm speakers to speaker wires of the amp

Basically, I have a bunch of speakers at my disposal and I'd like to take on a new project of building a cab and I was wondering if this was possible or if it would be a waste of time?

In doing some research, I came across this thread and the discussion turned towards more efficient speakers.">">

If my first question is ridiculous... I'll ask another based on this thread linked above. What kind of a volume gain would one get from a more efficient speaker? Would it be significant or miniscule?

Thanks in advance! Any info will be greatly appreciated


Re: Run a Spider IV 75 with a 2 x 16ohm speaker cab?
by spaceatl on 2011-12-12 20:22:57.1640

Two 16 ohms speakers should work....that would be an 8 ohm load...As long as you left the internal speaker disconnected I don't see much of a problem with that...I don't think that amp would play well with a 4 ohm load...

This kind of stuff voids the warranty, but it can be fun for those that enjoy this sort of thing...I did a similar modification to my Flextone III XL several years back to run a 212 in tandem...

More efficient speakers would give you more peceived loudness... Stock, you have 75 watts running into an 8 ohm load...The stock speaker is basically a Seventy80 or very close to that...That SPL rating is 98 db...If you found speakers with an SPL rating of 101 db or higher, then you would have the same loudness as using a 150 watt amplifiers with the same stock speaker...Basically a +3 db increase in SPL is the same thing as doubling the power...Sometimes SPL is called "Sensitvity"...Doubling the cone space by using two speaker will give you some additional volume increase...Also, if you use something like a sealed design you will gain some addtional efficiency...

Re: Run a Spider IV 75 with a 2 x 16ohm speaker cab?
by westicle1986 on 2011-12-12 20:31:16.9010

Thanks for the quick, super detailed response!

Ok, I will roll ahead with Project: Cabinet as planned. I had planned an open-back cab but I'll try the sealed route now.

I intend to keep the speaker (stock Celestion for now) still in the box, but I'll just disconnect it when I play live and use the cab I'll be building. My girlfriend bought the amp for me and I can't bring it back for the larger 150 now.

Thanks again! Your insight is greatly appreciated

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