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Discussion Starter #1
Hey Folks,
I have a questions. I'm running dual Shiva-X's off of a Behringer EP2500. This is a 3cuft box which is In-Wall and used for 100% HT only. The questions I have are regarding the Mode Switches on the back. What is the correct setting for my dual shiva setup in HT?

Low Cut Filter = On or Off? (If off, frequencies below 5 Hz are cut to prevent damage)

If ON Then 50 HZ or 30 HZ?

Clip Limiter On or Off?

Thanks for your help.
Cheers!
 

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You lost me there. The Shiva-X is dual 8 ohm, the sub is either wired in parallel for 4 ohms or series for 16 ohms. You must mean one sub wired for 4 ohms per channel of the amp.

With 650 watts into 4 ohms going to each sub, Xmax is not an issue.
Low Cut Filter = On or Off? (If off, frequencies below 5 Hz are cut to prevent damage)
If ON Then 50 HZ or 30 HZ?
That would be the high pass filter. Leave it off and turn the Clip Limiter on.
 

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Discussion Starter #8
Do you have an EQ? I am curious how those sound in such a small space.
No EQ. I'm on the market for a used SMS-1. Sounds great with Music, nice tight bass and great SPL. A little lacking in the low end for HT. I'm hoping a good EQ will fix that. If I had to do it all over again, I would just use a single Shiva-X for that box and go with a ported box.
 

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Your -3dB point if roughly 40Hz, which is why you don't get big impact with HT. Your Qtc is roughly 0.86 which is why you have "tight bass & great SPL". I would consider the EQ a bandaid and opt to rebuild in a large ported enclosure if budget can allow.
 

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mosconiac said:
Your Qtc is roughly 0.86 which is why you have "tight bass & great SPL".
Really it's an underdamped box and "tight bass" is actually bass with some ringing. That's the kind of sound the uninitiated like - nothing wrong with it, but I wouldn't necessarily call it tight.
 

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I wouldn't use an EQ to compensate for an under damped sub woofer. I've been there with my Shiva, and no EQ will help give you what your lacking. You can try stuffing the box with Polyfill first to loosen up the bass, this will extend the bottom end by a few Hz.

With a 3cu ft sealed box (and 3lbs Polyfill) I was able to get my Shiva down to 16Hz in room at -3dB. I was also feeding it 700 watts.

I was also able to get it down to 14Hz in room with a 5 cu ft box tuned to 16Hz.

They are very versatile sub woofers, and with 2 of them and a healthy amplifier, you have a lot of potential for some devastating bass. :hsd: Port those babies or give them at least 3 cu ft each sealed, that'll lower your Q to around 0.65 if I can remember from my Shiva days.
 

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Discussion Starter #12
Well, my options on the enclosure are limited. Here is what I've come up with so far:

Option 1: Remove one of the Shiva-X's and seal up the opening. This will give me a approx 3.5 cuft enclosure with 2lbs of polyfil for a single Shiva-X It will be powered by just one channel of my EP2500.

Option 2: Remove one of the Shiva-X's and install a passive radiator. I'm new to the passive radiator concept but from what I've been reading it's almost an "alternative" to porting. Since I cannot port the enclosure at this time (it's behind drywall) this seems like a viable alternative. The question I have here is with a 3.5 cuft box and 2lbs of polyfil am I pretty close to a single Shiva-X's limits already? If this is the case, a passive radiator may not be worth the minor help I'm getting from it.

I've been doing alot of reading over the last couple of weeks. I understand now that EQ is not the answer to acheiving lower bass frequencies. It's to get rid of the peaks which are making my bass response "uneven". Ie. boosting those boomy mids.

Please also note, I don't mind removing one of those Shiva-X's from the enclosure. This high quality driver will definetly not go to waist.

Once I figure out what my final enclosure will look like, I'll be moving on to the REWing stage for my setup.

Thanks alot for all your help, you guys are truley an invaluable resource.
 

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You are actually getting the most out of your sub as it is.

Purple is a single Shiva with PR's and a high pass filter to control over excursion.
Yellow is a single Shiva sealed with a high pass filter for the same reason.
Green is what you have, dual Shiva's with no high pass filter because over excursion is not an issue.

Shiva.JPG
 

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Discussion Starter #14
Thanks for the info Mike. I see around a 4db gain in the 20-30hz range and a much larger 9db gain in the 50hz region when looking at one vs two drivers.

My interpritation is that for music the two drivers are giving me great, high spl "mid-bass" but I'm not really gaining that much at the low end for HT. In fact I'm not sure I want that "mid-bass" for HT as it may overpower the sound track.

This sub is for 100% HT only. Am I on the right track in thinking one sub will suffice in this setup?
 

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You are actually getting the most out of your sub as it is.

Purple is a single Shiva with PR's and a high pass filter to control over excursion.
Yellow is a single Shiva sealed with a high pass filter for the same reason.
Green is what you have, dual Shiva's with no high pass filter because over excursion is not an issue.

View attachment 14757
To me that looks like he's not getting much out of his current set-up. With a QTC that high, your losing a lot of low end bass and getting a boost in the higher range. Those subs aren't getting used anywhere near there potential.

If you're going for a 100% HT set-up, tune low and go ported. Most people with Shiva's I've seen like 5cu ft and tuned around 18-20hz. Tune any lower and you start sacrificing mid bass. This thread has me wanting to dig out the old Shiva and build her a new home :T
 
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