[jmd1982]

hello all,

id like to ask you all for some wiring/configuration help to make sure i don't end up blowing any of my equipment. I am going to try to explain everything in as much detail as i understand, which is hopefully enough to help you understand what it is i need help with.

My equipment

1) Two 12" shiva-x's (http://www.diycable.com/main/product_info.php?products_id=653)
2) EP2500 amp
3) Denon - AVR-1609
4) Sealed dual 12" enclosure about 1.5cubic each chamber. (to be upgraded eventually)

Okay, it is my understanding after reading the pdf that goes with my speakers (http://www.diycable.com/main/pdf/shiva_docs.pdf)
that I can wire the dual 8ohm voice coils together in parallel to drop it to 4ohms. Then by connecting voice coil from speaker A to the voice coil in speaker B in parallel i can then drop them down to 2 ohms. Being that these subs are being used for music only, and my amp can handle the 2 ohm load, id like to do this.

At this point in time, i have the + connected to the + and the - connected to the - on each speaker individually. I then have 1 wire for each the positive and negative which will run to the terminal plate on the enclosure. (as seen below)



http://img195.imageshack.us/img195/4138/img00110200910251842.jpg

Question 1: so now each driver will be powered by 4 ohms correct?

the terminal plate on my enclosure resembles this one:
http://i16.ebayimg.com/06/i/000/d9/de/378a_10.JPG

now, how exactly do i wire my terminal plates to wire both voice coils in parallel, dropping it to the needed 2 ohms?

also where do they hook up to the back of the amp?
(which black and red knob do i use?)

http://img245.imageshack.us/img245/331/helpq.jpg

 

[Wayne A. Pflughaupt]

First - Welcome to the Forum, John!

Then by connecting voice coil from speaker A to the voice coil in speaker B in parallel i can then drop them down to 2 ohms. Being that these subs are being used for music only, and my amp can handle the 2 ohm load, id like to do this.

Why? There’s no good reason to do that. To get a 2-ohm load, you’ll have to connect both drivers to only one channel of the amp. That channel will be putting out a max of 1200 watts. That 1200 watts will be divided between the two drivers – IOW, each driver will get 600 watts.

Wouldn’t it make more sense to just connect one driver to each amplifier channel? It puts out 750 watts @ 4-ohms. So each driver will get 750 watts!

Not to mention, it’s much easier for an amplifier to drive 4-ohm loads than 2-ohm. It will run cooler and last longer.

I’d suggest re-working your enclosure and put in one termination panel for each chamber. That makes much more sense than what you’re doing now.

Regards,
Wayne

 

[jmd1982]

hey thank you for the reply.

from the reading ive done so far, it seemed as if 2 ohms was better for music purposes, unless i misunderstood the article. (2ohms was louder?)

also the enclosure has 1 plate for each chamber, sorry if that picture was retarded.

going with the 4ohm setup, id just connect 1 driver to the top black and red, and the second dial to the bottom black and red on the back of the amp correct?

 

[Wayne A. Pflughaupt]

from the reading ive done so far, it seemed as if 2 ohms was better for music purposes, unless i misunderstood the article.

Can't say as I've ever heard that one. Doesn't make much sense actually. Home audio manufacturers have been making outboard power amps for decades, so if that were true, they would have been making them 2-ohm all along. They didn't, they were mostly all 8 and 4-ohm amps. Sure, that may have been because the technology wasn't available. But it is now, and virtually no audiophile company - Bryston, Acurus, Adcom, Krell, etc. - makes a 2-ohm amplifier.

Regards,
Wayne

 

[jmd1982]

sounds good, as far as the hook up to the amp is it what i stated?

thanks again

-john

 

[Wayne A. Pflughaupt]

Yes - negative to black, positive to red.

Be sure and pay attention to the dip switch settings on the amp - make sure the low cut filters are off. Also, if you're running the amp from your receiver's subwoofer output, switch the amp to "Parallel." That way you only need one cable from the receiver to the sub.

Regards,
Wayne

 

[jmd1982]

got everything working thanks for your help very much appreciated!


as for the controls on the amp/receiver

do i want to put the amp all the way up (full power to each sub) and then control the volume to prevent clipping through the receiver?

or do i want to set the amp low and raise the volume through the reciever to increase the sub volume?

 

[booksmrt]

i would set the amp volume so that everything sounds good at your normal listening volume. the receiver volume should beable to handle it from there

 

[jmd1982]

the amp volume?

do you mean the amp gain?

the problem iam having is really annoying. It seems that the amp/subs are clipping way before they should be. Iam getting a decent amount of bass from the two 12's but no where near room shaking(and its in a very small room) Something is not right and iam not sure what it is.

 

[dyohn]

the amp volume?

do you mean the amp gain?

the problem iam having is really annoying. It seems that the amp/subs are clipping way before they should be. Iam getting a decent amount of bass from the two 12's but no where near room shaking(and its in a very small room) Something is not right and iam not sure what it is.

First, diuble check all your polarities. Having one voice coil (or one sub) out of electrical phase will drop your output significantly. Second, how do you know the amp is clipping?

 

[Wayne A. Pflughaupt]

Yes, wrong polarity could nuke it in a heartbeat. Also, did you make sure the HP filters are off?

Regards,
Wayne

 

[jmd1982]

polarities are fine, hp is off

my amp is currently connected to my receiver via an rca cable in the pre-out area which then connects to 1 bi xlr cable (one into port 1 on the amp and one into port 2)

is this correct or should i be using the "ext in" panel labled SW on the receiver

messing with the crossover frequency on the receiver seemed to help a bit but iam not exactly sure what they should be set at for music listening only purposes.

my 2 front speakers are

energy c-100's
* Recommended Amplifier Power: up to 110 watts
* Nominal Impedence: 8 ohms; Minimum Impedance: 4 ohms
* Frequency Response: 55 Hz-20 kHz +/- 3 dB
* Useable Bass Response (-10 db Anechoic): 50 Hz
* Sensitivity: anechoic 87 dB; 2 speakers in a typical room 90 dB
* Crossover Point: 2.6 kHz
* Overall Dimensions: 11.5" tall, 6.75" wide, 8.5" deep
* Weight: 11 lbs

with the 2 12" shiva-x drivers.