Axiom Home Page Forums General Discussion Technical Questions Thoughts on integrating a different into the mix

Hello fellow Axiom enthusiasts. I could really use some advice with a project I am seriously contemplating. I am currently running an Epic 60 system with the EP 500. Very happy with this setup for a few years now. Dennon 3808 powers all speakers.

I also have a very stout 15" Stereo Integrity MagD2 subwoofer that I previously used in my car. The sub sounds amazing in the car in a 3cf^3 sealed enclosure. After consulting the owner of the company about integrating the EP500 and the SI sub his responce was" I wouldn't run 2 different subs because you'll end up with 2 different sounding subs playing at the same time."You'll end up having 2 different f3s so one sub will loose output while the other sub is still playing."

I was wondering if there was an aux output from the sub channel of the EP 500 to drive additional amps and subs with the same processor functions. I was looking to enclose the SI magD2 in a 3.5cf^3 ported enclosure, and use it for below 60Hz and have a very strong 2.5 octaves of deep bass. The amp I would like to use for the SI MagD2 is a Dayton SA 1000 subwoofer amp.http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-811 The specs on the SI Mag D2 are 3.7 4 4.6 29.6 4.38 0.41 0.379 21.5 227 147 810 24 1000 91.5 I could really use some of your expert opinions here. Thank you for any replies

Demetrios, of course there's a line level output on the EP500 which allows for "daisy chaining" another sub. This is a minor convenience if the other sub is near by and a short connecting cable can be used between them instead of another one from the receiver sub out(where the processor is, of course)using a Y adaptor.

That is a valid point, but it really depends on your room. Some here have used different subs to good effect because two subs can really counteract a poor room response curve.

It is something you would have to try to see how it works in your situation.

Ok, so experimentation is the key to this project. The sub is a beast that has been designed as a SQL sub for car audio use. It has a fairly stiff suspension and recommended for a sealed enclosure with a volume of 3cf^3. According to the owner of SI, it also works extremelly well in HT use in a ported enclosure of 3.5cf^3 tuned to 30Hz. The sub is rated at 1000w RMS and has an efficiantcy rating of 92.5 SPL.http://www.stereointegrity.com/images/SI_Driver_List.pdf The model is MagD2V2.

If I daisy chained the SI sub from the EP500, would the processing of DSP circuitry be passed to the SI sub? I plan on purchasing a Dayton SA1000 subwoofer amp.http://www.parts-express.com/pe/showdetl.cfm?PartNumber=300-811 This is the only amp I could find with a dedicated infrasonic filter and delivers 1000w rms.

What are your thoughts on potentially utelising the SI sub to handle LFE at 60Hz and below, while allowing the EP 500 to handle LFE in the upper range above 60Hz? I have the time right now to construct a solid enclosure for the sub, but the $400 would hurt if the additional sub failed to enhance LFE and curb some of the peaks going on. I appreciate all input very much.
ps sorry for missing a key word in my topic. It was very late when I posted

No, the DSP processing is not passed through.

Demetrios, I suspected that you might be thinking that the EP500 somehow would do some processing for another sub, so I phrased my previous response to indicate that only the receiver would do the processing for the second one. The output for a "daisy chain" is simply an internal "Y" arrangement in the sub: one branch goes into the sub amp and the other just goes straight through to the output without being processed in any way. It's the same as if the connection to the second sub was coming directly from the receiver.

I'm really not following your proposal, especially the above and below 60Hz division. I don't know how that would be accomplished or what benefit would be had.

Although you have a sub driver now, it would seem that the expense and complication of an amplifier and enclosure for it might make simply buying another(less expensive)powered sub a better option.

Ok John thanks for the clarification. I may build the 3.5cf^3 ported enclosure since I have the driver and enough 1" mdf. I was thinking about borrowing an amp or even renting one and testing the sub in the listening room. If I'm not happy with the responce of both subs playing together, I can always sell the sub w the enclosure and put the money towards a 2nd EP500.

Using the subs to cover different frequencies is not going to smooth out any peaks. You want two full range subs properly placed in your room so that one sub will cover the voids created by the placement of the first.

WHat are you using to design/model this sub? To you have the Thiel/Small properties for it?

I have a buddy that uses pro box building software to design enclosures, primarily for car audio. He designed the 3cf^3 sealed enclosure that was used in my vehicle. The sub was powered by a JL Audio Slash 1000/1 amp and sounded amazing! A true SQL subwoofer. I am aware that car and home are two different animals. The Axiom system is my first HT experience as I have always been into high end car audio. The LFE in my home needs help.

I contacted the subwoofer manufacturer and the owner highly recommended a 3.5cf^3 ported enclosure tuned to 30Hz for exceptional HT results. The Stereo Integrity Mag D2V2 sub has been widely used in HT applications with great success. The sub is a beast weighing in at 56 pounds. I can't see how this sub won't make an amazing HT sub when enclosed properly and fed at least 1000w rms.

Here are the Theil/Small parameters
Re 3.7 Z 4 Le 4.6 Fs 29.6 Qms 4.38 Qes 0.41 Qts 0.379 BL 21.5 Mms 227 Vas 147 Sd 810 Xmax 24mm Watts 1000 Spl 91.5

I am currently running a JL Audio 12w7 sealed in my vehicle and have reached bass nirvana. This is the best sounding SQL subwoofer I have ever heard. No chance the SI Mag will ever make it into a future car install again. I appreciate any ideas and or feedback regarding this project.

OK, I gotta ask... cf^3? I keep reading it as cubic foot to the third power, which doesn't make sense.

It's a nine dimensional box.

To be honest I'm not quite shore what ^3 means in regards to enclosure formulas in cf. That is how the owner of Steroe Integrity has presented the recommended enclosure size. When you look at adavaced enclosure design software, the formulas for calculating optimum speaker enclosures from small/theil parameters, is a series of complicated mathematical equations. This type of math is not my strong point. If anybody out their has experience in advanced enclosure design, please give your .2.

I suspect that it is, in fact, a mistake.

I say just put some Axiom M80's in your car and be done with it!

Demetrios, yes both the T/S parameter Vas and enclosure volume Vb are given simply in cu.ft., not cu.ft. cubed. You've probably seen the formula for calculating the resonant frequency of a driver with a free-air resonance Fs and an "equivalent volume" Vas in a closed box of a certain internal volume. Apparently here a small closed box with a internal volume of 3 cu. ft. is being proposed(about 49Hz).

Thank you for your informative responce JohnK. Nothing ventured, nothing gained. I will be fabricating a 3.5cf ported enclosure tuned to 30Hz for the 15" Stereo Integrity subwoofer. I am able to borrow an amp from a buddy that's a sound teck for dance clubs and concert halls. I'd like to see if I can get the Ep5oo and the SI to blend well while playing full range. I'm sure it will be challanging and possibley yeild good results. Expect some build progress pictures to show up in the course of a couple weeks. I'll be checking back once I get the ball rolling. Thanks for any ideas

Can't wait to see some of the build as it happens. Good luck.

After questioning Nick Lemons, owner of Stereo Integrity of what the meaning of ^3 in reference to a 3.5^3 enclosure is...His responce was "the ^3 is mathematical shorthand for Cf or cubic foot. "It is commonly referenced this way in speaker enclosure design".

My buddy ran some numbers for various vent and port dimentions. Waiting on a responce from the manufacturer on port dimension recommendations. So far the best looking box utelizes a 2"x12" capped vent with box dimensions of 18"Hx22"W and a depth that depends on recommended vent type. I'm hoping to get this build finished within a week, time permitting.

I need to start looking at amplication for this sub. After researching the Dayton SA 1000 sub amp, I found that the amp barely puts out half of it's rated output. Any recommendations for amps delivering around 1000w rms into a 4 ohm load with an infrasonic filter? Keep in mind this is an experiment so budget is alo a key factor. Thanks

The ^3 wasn't a problem. It was combining it with cf that was confusing. One should use ft^3, or cf, but not cf^3, which says "cubic feet cubed" (and why I said ninth dimensional).

The f^3 actually should be written as ft³ (³).

Yes, Demetrios; feet cubed is correct, but not cubic feet cubed, which is what you were originally showing.

International League of Pedants, attack!

this is a good thread about amps used for subs:
http://www.avsforum.com/avs-vb/showthread.php?t=855865

Yes indeed...I made a mistake and I apologise for typing it that way. Now I understand. Thanks

No shortage of those around here.

Your so-called "sentence" is lacking a verb.


Hey, grammar Nazis are pedants, too.

I could always switch to writing like BBigwyres. Well, maybe I couldn't but...

Just inject your knuckles with novocaine. The rest is easy.

You're on a roll tonight.