[andyr]

Andy,
I struggled with the same question some months ago... bass driven by one souped-up 100 driving woofers in parallel or one 55w per driver?  SL certainly recommends one 60w amp per driver, and if I was in your position with six 55w modules, I'd buy two more and be done with it.  In my case, I only had four 55w modules and so it was a matter of buying four more 55w modules or two 100w modules.

With no passive xo components in the chain, 55w driving a 90.5db midrange driver should have plenty of punch ...

Hi Peter,

Thanks for chipping in.  Yes, after reading an earlier post of yours, that's what I understood you to have done.  My "problem" is - I don't have 6 x 55w AKSA modules (Hugh seems to have forgotten this fact   ). ).

So... this influences what I need to buy for the remaining 2 modules - should I buy a 100 (so each Peerless can be driven by it's own 100 module) or a 55 (and use my 100 on the mids).

You see, I want the "ultimate" - 4 modules per Orion.

I've read the reason why SL says "use only 60w (into 8 ohms) amps" ... so you can't burn out the Peerless voice coils (the amps just run out of puff, instead!).  However, I do not play my music at head-banger levels, so I'm never going to get to the dangerous situation.

Gut-feel tells me a 100 is better for the bass because of the extra dynamics that it exhibits ... and this also provides more headroom than a 55 (because of the extra power) for milli-second dynamic peaks - which I believe are important.  However, I'd like some one else to corroborate my thinking!  

Regards,

Andy

[AKSA]

Hi Andy,

I see now, thanks for the explanation.

I cannot see how 100W would hurt the sound, so, in the interests of using your existing 100s, you could add two more, one for each driver.

You could run them at lower rails, say 42V like PSPs, and then you could fit two onto the same heatsink!

Cheers,

Hugh

[PSP]

SL's rationale for limiting amplifier power in the bass is to avoid physical damage to the woofers.  Damage control will thus set the ultimate SPL limit.  If you want more bass, there is the Thor, one per side.  Most Orion owners recommend building the Orion first and then deciding whether to add Thors.

In my case, I'm quite sure that I'll be happy with the Orion as-is.  For movies, I will XO the Orion (at 50Hz) to my existing VMPS new original sub through the HT reciever.  For HT, SL recommends off-loading the bass to a sub, because in HT there are no reasonable limits to how loud the bass can be and damage to the Orion woofers could result.  In most music, the bass is in some sort of reasonable proportion to the rest of the spectrum... not so in HT.  In case you can't tell, I'm much less serious about HT than I am about music.

Another option is to build the Phoenix... perhaps not as refined as the Orion (but by how much?), larger, and--I understand--way louder.  Tinker seems to be very happy with his Phoenix setup.

So many options, so little time and money...

good luck,
Peter

[eweitzman]

You don't have to play music at headbanging levels to push the woofers past their stops with a bigger amp.

The first time I did it was when the subharmonics in Patricia Barber: Modern Cool got through. Never knew they existed before. It sounded like the CRACK that preceeds the boom of a thunder clap, or an elco cap exploding. The 12Hz rumble in McCoy Tyner: New York Reunion was also very unexpected. Pipe organ at 16Hz? If you play records, you can expect the cart/arm resonance due to cartridge compliance, normally in the 5-15Hz range when riding warps and off-center records, to push the woofers too far. Keep in mind that the lower the frequency, the higher the boost from the dipole EQ in the crossover.

- Eric

[andyr]

You don't have to play music at headbanging levels to push the woofers past their stops with a bigger amp.

The first time I did it was when the subharmonics in Patricia Barber: Modern Cool got through. Never knew they existed before. It sounded like the CRACK that preceeds the boom of a thunder clap, or an elco cap exploding. The 12Hz rumble in McCoy Tyner: New York Reunion was also very unexpected. Pipe organ at 16Hz? If you play records, you can expect the cart/arm resonance due to cartridge compliance ...

Hi Eric,

Thanks mmmm ... food for thought.  BTW - WHAT subharmonics in "Modern Cool"??     I've got the new MoFi 45rpm (I think?) and I don't hear no stinkin subharmonics through my Maggies!     Haha - that's why I want Orions!

Can you just run this logic by me again?  If I have a 60w amp powering each Peerless driver then, when the subharmonics in "Modern Cool" arrive, the 60w amp will start pushing the woofers out ... but they won't get to their stops bcoz the amp will run out of steam before the driver reaches the critical (damage) point?

Whereas with a 100w amp there'll be so much more power available that the driver will just keep on going out past its stop!!??  

Do I have this right?

Regards,

Andy

[eweitzman]

Andy,

You have it right.

When the 60w amp clips, you might hear the clipped signal. It can't sound too nasty because the driver won't reproduce the higher harmonics. With my Haflers, the clipping makes a very brief "whoop" noise on the beat. Most people don't notice it until I show them the amp's clipping LEDs.

- Eric

[eweitzman]

I ... put additional tantalum caps as bypasses for all the opamps in the ASP. I read somewhere that it was a good idea and it is also in the BB application notes. I think I followed their suggested values of 3.3uF tantalum and 0.01uF (the SL specified Panasonics)

I was curious about this so I checked the application note. It say to bypass with 10nF or higher ceramic caps, but doesn't mention 3.3uF. Perhaps you read this somewhere else.

- Eric

[andyr]

Andy,

You have it right.

When the 60w amp clips, you might hear the clipped signal. It can't sound too nasty because the driver won't reproduce the higher harmonics. With my Haflers, the clipping makes a very brief "whoop" noise on the beat. Most people don't notice it until I show them the amp's clipping LEDs.

- Eric

Thanks, Eric.

Regards,

Andy

[stvnharr]

Don't mind if I ask a side question since so many of you here have experience with Orion. Have anyone here listen to John Kreskovsky (aka John K) NaO and how would you compare it with Orion?
http://www.musicanddesign.com/naomain.html
As NaO only need 4 channel of amplification, it is a better dipole option for me.

TIA,
Sam

Yes with Orions now the rage of the moment, it's good that Sam mentions John K's Nao speaker.  There are some variants to the original design, including one with Seas Excel W18's, which SL really liked if you read his mid woofer tests.
But in order to really have a dipole speaker one must have a dipole friendly room, meaning large.  
Another option worth considering if room, finances, etc. need time to work out, is to go with a speaker with the same drivers as in the Orion.  The Seas Trym kit uses the W22 woofer and TC25 Millenium tweeter in a 1.1 cu.ft box.  Kit design is on the seas website at www.seas.no.  Then one can construct a subwoofer with a Peerless 12" XLS driver.  There are many designs one can use here.  Of course additional XLS drivers would still need to be purchased in the future.
While the Trym-subwoofer option is not really a poor man's Orion, it still get you part way there, while everything else shapes up.

[eweitzman]

I don't think of the Orions as the speaker of the month. People have been building them steadily for three years now.

The Joseph Audio Pearl uses the Seas drivers. It's a fantastic sounding speaker for $20K.

[MikeC]

I ... put additional tantalum caps as bypasses for all the opamps in the ASP. I read somewhere that it was a good idea and it is also in the BB application notes. I think I followed their suggested values of 3.3uF tantalum and 0.01uF (the SL specified Panasonics)

I was curious about this so I checked the application note. It say to bypass with 10nF or higher ceramic caps, but doesn't mention 3.3uF. Perhaps you read this somewhere else.

- Eric

My memory is partially (but not completely) fallible. I checked through my disc of files - it is the AD826 application note. Almost all the schematics show this configuration. I also think it is mentioned on DVV's site.

Cheers

Mike

[stvnharr]

I don't think of the Orions as the speaker of the month. People have been building them steadily for three years now.

The Joseph Audio Pearl uses the Seas drivers. It's a fantastic sounding speaker for $20K.

The Pearl is very expensive.  It does use the Millenium tweeter.  The other drivers are the W15 and a pair of L22's.
Another commercial speaker that uses all Seas Excel's are these http://www.tyleracoustics.com/linbrook.html, for considerably less money than the Pearl.

The Trym and sub would be at around $1k if done completely diy.

I remember reading about the Orions when SL first was writing about the project.  They looked to me to be "The One".
You are correct in that they are not exactly the speaker of the month, but the speaker of the past 3 years, and for the next umpteen years as well.

[andyr]

... But in order to really have a dipole speaker one must have a dipole friendly room, meaning large. ...

Steven,

Are you shure about this?     I've done some investigation of the NaO after Sam's mention of it and John K indicates there are few, if any, advantages of dipole bass in a large room (mine is about 4,500 cu ft).  I came across the following statement - as you'd be aware, the latest NaO can be changed from U-frame (dipole) to sealed box (monopole) by putting the back of the U-frame cabinet on:

"The major significant difference between dipole and monopole is the inability of the dipole to pressurise the room below the room fundamental.  This has an advantage when the room fundamental is above the cut-off frequency of the woofer (ie. small room), since a dipole will adapt to the room fundamental with little or no bass boost ... whereas the sealed-box woofer (with cutoff below the room fundamental) can exhibit significant bass boost and can 'boom'.  However, in a larger room this is not an issue."

So I'm wondering in my large room maybe a sealed-box woofer system would be preferable, since this means the same dual 10" Peerless woofers would have about a 1/4 the excursion they would have in a dipole setup ... so the potential for damage that Eric talked about would be avoided??  

Any comments, anyone?

Regards,

Andy

[eweitzman]

The major significant difference between dipole and monopole is the inability of the dipole to pressurise the room below the room fundamental.

That's an interesting idea but it doesn't make sense to me. At some frequency where 1/2 wavelength > the longest room dimension, standing waves don't appear and the room "pressurizes". I don't see why the air in front of and behind the dipole won't pressurize when the wavelength exceeds this, in opposite phase as usual, and why the pressurization won't continue to cancel in the plane of the baffle when these pressure zones run into each other.

I guess I'll have to take my Orions into the bathroom and see how they sound.

- Eric

[SamL]

 I came across the following statement - as you'd be aware, the latest NaO can be changed from U-frame (dipole) to sealed box (monopole) by putting the back of the U-frame cabinet on:

The u-frame that John K uses for his bass drive is cardioids (unidirectional) not dipole. There were heated discussion on madisound forum a while back when John K first brought it up comparing it with dipole. http://www.musicanddesign.com/u_frame.html

[stvnharr]

I've not read much on the Nao.  
My thoughts on a "large room", with no definition of large refer more to having a room large enough to have the speakers out quite a bit from the rear wall without a bunch of other stuff in the room.  I suppose a nice "audiophile type" room, whatever that might be, would be sufficient.

I just got thru looking at SL's website, for first time in long time, and I came across his new Pluto project,  http://www.linkwitzlab.com/Pluto/intro.htm.
Seems to me that a single Aksa 55 could work wonders here, although the amp and active crossover are all on the same board.  I'll have to look into the Pluto some more.


Steve

[Lexicon1]

Does anyone know if someone has used the DEQX PDC 2.6 as a digital crossover (to substitute the stock crossover) and room equalization or its possibilities?
I realize that the SL crossover is complex , but can it be emulated and adjusted for room tweaking?
If this is an option, it seems to make sense that you can tame room issues?
I believe there was one fellow in Australia that was working on it, but did not have enough memory to integrate a sub.
Any comments?

DEQX website is below

http://www.deqx.com/pdc26.html

[PSP]

Philip,
Many posts ago on this thread you mentioned using two ASP boards per channel to accomodate the GK-1's sub out option.

I have the GK-1R and will be building the ASP soon.  I'm wondering if I should follow your path and buy two more ASP boards from SL.  Can you comment on the Orion bass from the GK-1 sub out vs. the GK-1's main output?  How much difference does the tube stage make in the bass?

Many thanks,
Peter

[SamL]

I believe there was one fellow in Australia that was working on it, but did not have enough memory to integrate a sub.
Any comments?

Guess you must be refering to Steve Dodds.
http://www.doddsy.net/steve6_001.htm

[Lexicon1]

Thanks for the reply, but , the DriverRack is a different unit than the DEQX, and he did not use the same drivers as the Orion.
Was curious as to a side by comparison between someone who actually built the Orion and its crossover vs having the flexibility of room correction.
Thanks