OT - Home Stereo Hi-Fi - Help Me Plan

Thanks so much for the reply. Sorry for the slow response. I've been working like mad lately. Getting a few hours of sleep has taken priority over posting on lengthy replies. Finally I have a bit of a breather today...

1.   Alright. First question. I read conflicting information all over the web regarding whether 2 subs are better than one in a stereo system (not HT). It would seem to me that it makes sense to use 2 unless you have a steep xo point below 80hz (that's where bass starts losing it directivity, right?).

2.   Ever since my recent enlightenment regarding the benefits of the 'shortest path' I've been trying to think of how to best design my system around that goal. On that note, do the speaker outputs of those subwoofer plate amps degrade the sound quality?

3.   I've been thinking about trying one of those passive pre-amps. Do you know if the Creek OBH-10 was built to the same quality as the OBH-12? I know it doesn't have the switching feature, but I don't anticipate needing that.

4.   I've been thinking about moving to an RME-Audio card with analog outs. Reviews have said the DACS + Analog outs on these cards rival most very expensive external DAC solutions. My question is this: if I go passive, do I need to concern myself with some sort of output spec (voltage, resistance, etc.) to ensure that I don't need the gain that an active pre provides?

5.   Here's my "realistic goal" system right now. It will have to be a work in progress, but let me know what you think:

RME Analog outs --> Creek OBH-10 ---> Marchland 48/db 2-way xo @ 70hz --->

6.   With a 48db xo at 70hz it would seem reasonable to seal the Kit61 because of the great extension the extremis provides. The low xo point the extremis can handle, combined with the 48db octave slope should allow me to run a single subwoofer successfully, right? Am I mistaken here? I've always liked the sound of sealed speakers better.

7.   On that note. In your opinion, would it be better to seal the subwoofer, then with a plate amp provide a gentle low freq. parametric eq boost around 25-30hz, or port the subwoofer?

Thanks again! -- Oh, I'm located in good old Iowa, quite a distance from so-cal.                               

The extremis mid is more designed to work in a ported enclosure.  In a sealed application you are only going to get response down to the 65 Hz range.  This means you aren't really going to take advantage of the huge excursion it has available.  It will allow you to play the mids at a higher volume level without breaking up, but that really wasn't an issue anyway given my experiences with these speakers thus far.  I'd recommend porting the mids and running a single sub crossed over at say 30 Hz and down.  This way you won't have to worry about soundstage issues as the front speakers will be taking care of any directional content. 

This will also allow you to design the sub for a smaller bandwidth, narrowing your options.  Although the CSS 10 is a great performer, I don't think it would be the right choice for my suggestions above.  I'd recommend a sub that will play down deep (low Fs and long excursion) in a tiny enclosure.  According to Hoffmans Iron Law, this means you are going to need some power to run it and an amp with a good parameteric EQ.  Just don't be surprised if you need a 600+ watt amp. 

Steven Kephart

Adire Audio

Steven,

Tumult w/ ADA1200 more what you're thinking for me?

An extra $1k bumps up the cost to this little system - I guess the Tumult and ADA1200 would be fit to make a long haul though.  In the interest of saving money, with that low of a xo (~30hz) point, you're right - I wouldn't have the stereo image issues - even with a 2-4 order xo. 

Your ADA amps don't have a high pass out either via low or high level, right?  Does anyone know of a cheap(er) than Marchand xo that would sound great for crossing mains over to a subwoofer at ~35hz?  A DIY solution even? 

I'm assuming y-cables won't do the trick.  What kind of effect on sound quality would y-cables have in the chain? 

On the ADA, any chance your engineering boys could throw on a fixed frequency 24db high pass pair of pre-outs for an extra $200 or so? ;-)

Thanks!

Well I was actually thinking a 12" Tumult when they finally come out.  Either that or a Brahma 10 in a 1 cubic foot sealed enclosure  But I figured the ADA amp might have more capability than you need.  So if someone else offered a decent plate amp with a single eq, that would work fine as well.  It would probably also save you some money. 

How large of an enclosure are you willing to go?  Remember, the larger the better for low frequency extention.  It will be much easier on the subwoofer, amplifier, and system.

We do have a high pass filter on the ADA amplifier.  It is 4th order set at like 2 Hz (disabled).  It is designed as a ruble filter that we could add for a customer.  I talked to one of our amplifier engineers and he said that it would cost a lot of money to add the outputs with crossover functionality like you want.  But he said the best thing to do is buy a car crossover and a wall wart to power it.  That's what he did for a while.  His is an a/d/s/ unit that he is trying to sell right now.

Using a Y-adapter shouldn't effect anything.

Steven Kephart

Adire Audio

Tumult 12", huh, interesting.   :-)

On the enclosure..  I could live with anything less than 3ft^3.  I don't need an ultra small box.

Thanks for checking on the high pass filter for me. 

Also, how do you feel about running the Tempest instead - in the name of sound quality would I really miss the XBL technology?

Thanks!

Ah, I was under the impression that we were going as small as possible.  That is good to hear.  Then actually the CSS 10 would probably work just fine.  Although since you can go with a little larger enclosure, then I would recommend going with a 12 or even a 15. 

The Tempest is a great budget sub.  It has awesome sound and performance, especially for the price.  But I am hooked on the XBL^2 sound.  It's like what high definition is to tv IMO.

Steven Kephart

Adire Audio

Unfortunately no I haven't.  But I do have one of his Clarus subs at home for my small system.  It is a great little performer.  But I haven't tested it on the really low stuff as I live in an apartment. 

I do have some good listening time to XBL^2 ported in our Sadhara sub.  But I haven't heard a PR alignment with one yet.  I can't see it being much different though.  The Sadhara is one of my favorite subwoofers for movies.

Steven Kephart

Adire Audio