[MaxCast]

Jay, the xo is what I was getting at in my post on the first page.  I have the Hypex sub amp and sm6.9's which start to roll off about 40.  I find a bit too much overlap.  I wish the sub would start at 40 or even better 35 like the ACI's.  The Hypex does have great thd specs and has a built in high and low pass xo's.  It also has a variable boost feature which you can use if needed.  I have not needed to use it.  Now that I have a different preamp I will try the internal high and low pass xo's on the Hypex.

Since your speakers go even lower I think you will need a xo point of 30-35 to intigrate well.  You may even want to consider a merchand or IRD xo(if he ever gets it to market).  This would allow you to choose any xo point you want and off load the first and second octaves on your 9's if you wish.

And you thought adding a sub was going to be cheap and easy     more wires more ac cords more challenges!!  I don't have a record player but I think subs and monitors are the hardest to get right.

Are you going for one sub or two subs?  Do you have an idea of where it will be?

[Jay S]

Yeah, I was hoping to be able to plop down a single box and be done with it!     It may still be possible since the XO of the ACI Force goes down to 35 Hz and has a 4th order slope.  Too bad the Paradigm X-30 is only 3rd order (though maybe that's steep enough if I use a 35 hz cutoff?).

The VBT has been reviewed to blend well with the SM6.9... I am not too clear on exactly what the low pass frequency cutoff and filter slope is as the specs and the review given unclear/contradictory info.  

An external XO (IRD, Marchand) would let me choose an even lower cutoff frequency but I really don't want to go that route, for reasons of complexity and cost.  Its for that reason that I will not high pass my 9.0s.  I really don't need another main amp and another high quality IC.  

In terms of placement, I am thinking of putting a single sub between and slightly in front of my main speakers.  If I get 2 subs then I'll have one to the outside of each main speaker.  Having continuously variable phase control will help me to compensate for any differences if the subs are closer/further from my listening position compared to my main speakers.

[MaxCast]

Don't you ever sleep?      

Subs are like buying a house:  location, location, location.  I never believed in the posts saying, "I moved my sub just a few inches and it made a big difference."  I do now!

There may be a sub out there that comes with a plate amp which goes sown to 30 on xo, but I'm not sure...stryke maybe???

I crused through that review and found it hard to follow also...one of those must read three times reviews.

Good luck, Jay.

[Psychicanimal]

 I can't imagine shipping a 130 lb sub all the way to Hong Kong.

Why not get a driver and have a cabinet built?

[KevinW]

Another thought... use the built-in internal active XO of the Hypex HS200 amp?  This XO uses very high quality parts, and doesn't degrade the sound of the high pass outputs at all.  You would almost certainly benefit from reliving the 9.0s of their duty below 80 Hz.  Bass would be improved, as well as mids.  And you wouldn't need an extra amp or external XO.  All you would need is a second set of cables.

It's also important to realize that anytime someone says that they hear "boomy bass", it could also be a room response peak causing this, and not the brand of sub or XO point.

[MaxCast]

Another thought... use the built-in internal active XO of the Hypex HS200 amp?  This XO uses very high quality parts, and doesn't degrade the sound of the high pass outputs at all.  You would almost certainly benefit from reliving the 9.0s of their duty below 80 Hz.  Bass would be improved, as well as mids.  And you wouldn't need an extra amp or external XO.  All you would need is a second set of cables.

It's also important to realize that anytime someone says that they hear "boomy bass", it could also be a room response peak causing this, and not the brand of sub or XO point.

Kevin, I'd be interested to know more about the ingredients of the hypex xo.  I can't find their web site anymore, but from what I remember it didn't have that much detail anyway.  I have this amp and was considering dualing   subs but am concerned with running through that xo.
TIA,

[KevinW]

The Hypex brand of amps are built by Hypex exclusively for Adire Audio.  Here's a link to the HS200.. http://www.adireaudio.com/diy_audio/amplifiers/hs200.htm

The quality of the active XO certainly approaches that of the Marchand XOs.

The Rava SE uses the Hypex amp.  I have one very happy customer who is using the active XO of this amp with his full-range speakers.

[MaxCast]

Thanks Kevin.

[Jay S]

Kevin,

That's a good reminder.  I have read great things about the high pass XO of the Hypex and it does represent an incredibly good value.  If I were reasonably sure that I would place the sub between my main speakers then I would be able to use the high pass XO (though I would have to get 2 2m interconnects, which may well match/exceed the cost of the sub since I would not want to degrade the signal going to my main speakers!).  

That said, if I end up putting the sub further away (and I am not sure how likely this would be) then it would not be practical to use the high pass XO, in which case the low pass of the Hypex (just 50 Hz) may not be low enough if I am running my 9.0s full range.   If only the low pass XO went lower... and while we're at it, it would be good if the phase control of the Hypex were continuously variable instead of being a 2 position (0, 180 degrees) switch.

[KevinW]

Yeah, using the Hypex for active XO certainly does have some placement limitations.  However, I would also highly suggest that if you cross over at a low frequency, you should absolutely place your sub in the same plane of the speakers.  Or else you will have phase problems, even with a continuosly variable phase control.  

Aside from using the active XO on the Hypex, if you have DIY skills, I would highly suggest getting the basic Marchand... the XM1. It will set you back about $100, and will have better sound quality than the more expensive Marchand models (simpler circuit and no icky pots). Especially if you use the high quality Burr Brown op amps.  Then you won't have to pay a bunch for cables either.

I do recommend using an active XO, as that will indeed result in a large increase in midrange SQ for a 2-way speaker that attempts to produce bass down to 30+ Hz.

[EProvenzano]

I'm not sure about the rest of the Marchand lineup, but the XM44 has stepped 1db switches not "icky pots".

Also, I would guess that the bass overlap I was experiencing was not due to a room interaction because it went away entirely after I added the XM44. Leading me to believe that the bass hump I was hearing, was due to the xo low pass being set too high. In my case the lowest setting was 30hz after mods. This still wasn't low enough for my 1801's to integrate with. I know that the 30hz mark is not likely acurate, but the point is, if your mains are pushing 30hz f3...good luck filtering out the sub above that point. I don't think it's posible with the plate amps I've seen out there (and I've heard a few too).

I've been down the road Jay's on right now. I wish I would not have wasted my time. The flexibility of the active xo's is excellent. They are pricey tho, and I certainly needed to save my pennies for a few months.

BR,
EP

[doug s.]

hi ep,

when i ordered my marchand xm-9LL several years ago, i was gonna splurge for the stepped attenuator switches.  phil marchand talked me out of it, saying this was offered only for those who yust couldn't sleep well at nite, w/o 'em.        he said his "icky pots" were the sonic equal of the stepped pots, but he had to offer the stepped iterations cuz of audiophile marketing pressure.   i guess he's not from the frank van alstine school of marketing...  

but, this, i agree on - in the long run, the marchand active x-overs offer greater system flexibility & better sonics than any powered sub solution, regardless of what sub ya fancy.  

and, being able to transparently cross over yer monitors, eliminating their having to handle low frequencies, is one of the main benefits of subwoofin', imo - yer monitors' midrange & upper bass will improve markedly.

doug s.

[Jay S]

I agree that an active XO would be great to have.  But I think that it will be something to look into down the road -- not sure if I want to bite off on that level of complexity and cost at the start.  I'll probably just start off with an active sub with a good plate amp and a long IC of moderate quality so that I can experiment with different locations.

I could try the sub on the same plane as the main speakers, though it would then be several feet further away.

[doug s.]

jay, re: powered subs, remember what jerry said prewiously about the yamaha subs...

http://www.yamahashoponline.com/searchresults.asp?dept_id=17

the prices at that link include shipping, dunno if it covers the far east...  

doug s.

[Jay S]

Hi all,

Thanks for all your suggestions and advice.  After lots of consideration, I have placed an order for an ACI Force subwoofer (with rose walnut side panels).  This will be my first subwoofer.  I'm looking forward to a whole new experience!  

I'll also get ACI's 85 Hz passive high pass filters if they can be modified to work at the output of my preamp.  They are directional, designed to go at the input of the amp.  Is it as simple as swapping the male and female RCA connectors?  

Hmm.. how about an upgrade to the fixed power cord....  

[Marbles]

Congrats Jay....

Be careful with those passive filters..many think they rob the system of dynamics.

When your bank account recovers, Wayne builds Marchands now and IRD's PT-2 has gone to production, so you will have some very nice active XO's to chose from.

[DARTH AUDIO]

I own the force and like it a lot.. I use the Force with a pair of Merlin TSM-M's. The force is in my music only system..  The bass is great for a small sub. I like the fact that its small.. Not in the way.. Enjoy

[TheeeChosenOne]

Jay S,
Welcome to our side of THE FORCE.  

Rest assured you'll like it....a lot.  

[Jay S]

Thanks all!  I'm really looking forward to getting THE FORCE!  Speaking of letting the bank account recover... shipping charge to Hong Kong is no joke... US$199!  And that's with ACI's corporate discount.  

An active XO may well be in my future... just not now.  By the way, I've read of active XOs (from LC Audio, I think) that sit in the speaker and replace the passive XO board... which would be cool since they would eliminate one set of interconnects.  

I have read mixed reviews of the passive filters... but for $29/pair I am willing to try.  Who knows, I may end up with a tweaked version using Bullet Plugs and Unobtanium capacitors and resistors!  

[Jay S]

Hi all,

The FORCE is in the house!  It got delivered yesterday morning by UPS.  It was very well packed (double boxed, with thick packing insulation) and was in perfect shape after the long trip to Hong Kong.  

I got to unwrap it prior to running off to the office (yeah, busy weekend!).  The rose walnut panels are nicely finished.  I got to hook it up last night.  I plopped it in between my main speakers (using a "free" 1.5m IC I got with a tv or vcr; I've got a Bolder Cable 4m M-80 subwoofer IC on the way) and plugged it into my balanced power supply (which has a 1200 watt transformer).  So far, so good.  The Force is adding a bit of foundation and punch to music and movies, though I am not going to seriously listen till I get it broken in and can play around with setup.