Jon, about the Shivas...

 

Suicide-Shifter
Unregistered guest
You say the shivas are run good on the jbl 600.1 but if they are run on the 1200.1 would they be any louder or would they hit any harder? and on the 600.1 would it be run on 2 or 4 ohms?
 

Bronze Member
Username: Jayj

Post Number: 63
Registered: May-04
Well since they will have more power going to them yes they will be louder but the risk of burning them up is higher. Due to the heat build up. And if they are running on a JBL 600.1 and if they are the 4 ohm SVC version then they should be ran @ a 2 ohm load since this will give them all the power the JBL can give.
 

Silver Member
Username: Jonathan_f

GA USA

Post Number: 382
Registered: May-04
Really it depends on the box. If the box is small, you'll need more power to get full mechanical x-max of the sub. If the box is larger, or a good ported box, the sub won't need as much power to reach it's mechanical limit. I'd do a sealed box 1.5 cu ft. per sub, off a JBL 600.1, it's plenty. If the box is small (less than 1.0 cu ft per sub) I'd do a 1200.1. Basically if the box is big enough to allow the sub to reach full excursion at 300 watts RMS, then that JBL 1200.1 will hit full excursion more often on less demanding songs (songs with a less intense bass line). But assume you play a song where the 600.1 will push the sub to max excursion, the 1200.1 on the same song will also hit max excursion, SPL will be the same at that point in the song, but the 1200.1 will pull more current and the voice coil will generate more heat. If you want the total maximum capabilities of that sub over a broader requirement, then a 1200.1 will hit max SPL more often than a 600.1. The coil will be very close to it's thermal rating, though, and the amp will draw a lot more current, just keep that in mind.
 

Silver Member
Username: Jonathan_f

GA USA

Post Number: 387
Registered: May-04
More simply put, say two Shivas in the right box needs 300 RMS each, 600W total for reaching x-max, any point where the 600.1 isn't putting out full RMS output, say a quieter part of the song where the amp puts out 400WRMS, 200W to each sub, then the 1200.1 will put out 800W on that same part of the song, 400W to each sub, pushing the subs to x-max. But the 100 watts more than 300 (which was all that was needed to reach x-max) will be wasted as heat from the voice coils and current draw from the charging system. That's why you'll see max excursion more often with a 1200.1. You'll see more SPL because the sub will hit full excursion more times with the 1200 than with the 600, but the maximum SPL will be the same (give or take a little).
 

Silver
Unregistered guest
Awesome. this was a really good answer to a question I had in another post. Thx Jonathan
 

Bronze Member
Username: Virulentv

Post Number: 18
Registered: Mar-04
Well, i had the same question as i was getting jbl1200.1 cheaper than the jbl600.1. jbl1200 is costing around $215 and the jbl600 is around $240. the difference is not a problem but i was just thinking if at any point i would like to upgrade to brahmas or anyother than jbl1200 would come in the right role. anyways is there any way for the jbl1200 to perform for 2 shivas without heat dissipation or current drawing?

thanks all.
 

Silver Member
Username: Jonathan_f

GA USA

Post Number: 426
Registered: May-04
Just turn the sub level on the head unit down, or turn the gain down on the amp, that way the amp isn't as sensitive to the input signal (If your head unit puts out 4V, and the amp is set to be sensitive to 5V, then you will only reach 4/5 of the power before the head unit sends a clipped signal) Anyway, that 1200.1 won't harm the Shivas unless you're extremely aggressive with it and drive the amp into clipping, but you'd be deaf by then, anyway.
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