Orion questions

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I heard a pair of Orions a couple of weeks ago and was impressed to the point that I'm seriously considering building a pair of my own this year.

Although the Orions look smaller in person than the photos I'd seen online, they're significantly larger visually than my current monitors, hence not needing to add a sub (for modest HT use) would be very handy.

So--how much impact would using one of the longer stroke 10" woofers like the new Adire units (18mm one way) or even a 12" like the DPL 12 have on the bass output?

A second question about amplification: would it be detrimental/problematic to hook up the 2 bass drivers in series? I've got a Nirvana'd 100W AKSA running my current 2 channel system. Adding 2x 55W AKSAs for the mids and tweets would probably be doable financially and space-wise in conjunction with my 100W for the two woofers, but 4x 55W AKSAs would break the bank. Or don't these speakers sound any better with amps like the AKSAs than with the chip amps?

Thanks for any inputs!

🙂 Dayne
 
I've heard the Orions, too, and I think you'd be hard to go wrong building a set of those if you enjoy DIY construction.

If you are comparing against the XLS Peerless woofers used in the original design, 18 mm Xmax isn't picking up all that much more than what the Peerless offer- be careful to compare nominal sensitivity, because that usually drops dramatically as the Xmax goes up, which ups you're amplifier power quickly. For example, between a driver with a nominal sensitivity of 90 dB to one of 87 dB (let's even ignore impedance for the moment), you could be talking moving between a 100watt/ch amp and a 200watt, especially considering the LF eq requirements. Of course, drivers with higher Qts than the Peerless will reduce the EQ mandates somewhat.

It also depends on how low you want to EQ; a set we built with 2 DPL12's from Adire on each side sound quite nice with just 6 dB of lift at 40 Hz, and stopping the EQ at that point. But they won't do the 20Hz stuff and below with HT material. Stopping the boost at a reasonable frequency may prefent over driving them, too.

For reference level HT playback, I'd consider using a monopole sub below ~ 50-60 Hz. Above this frequency is where you seem to get most of the dipole benefits.

Hooking up the bass drivers in series is possible, but then you need more voltage to drive them. I have one set of dipoles (not Orions) built with the drivers in series (they're 4 ohm drivers), and one set being built with them in parallel (they're 8 ohm drivers). The latter is more sensitive overall, of course, but requires a little more guts from the amplifier.

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I haven't heard any of the chip amps; the AKSA's I've heard and are good, and I'm using Ayre and Aragon myself.

The system with the parallel drivers using SCC300's will be an all passive crossover, and I'm not sure whether the Ayre V5 will be as much as I need (150 watts per channel), or whether I'll use something a little higher power, like some Aragon Palladium's I've been modifying.

Best regards,

Jon
 
Assuming you're not power-limitted, volume output will increase by 20 log (new useable Vd / Vd of the Peerless XLS). Other woofers are not useable out to xmax.

Monte Kay's angled driver mounting allows you to squeeze a 12" driver into a narrower width, perhaps where 10" fit so you won't mess with the polar response.

Before I built my Orions, SL's splx_max1.xls spread sheet suggested a maximum output of ~105dB at higher frequencies when you limit excursion to xmax. The woofers hit xmax arround 118dB @ 80Hz, 100dB @ 40Hz, and just 82dB @ 20Hz (which is 6dB down due to equalization, so you could consider the maximum input to be for 88dB).

Unless you can get another 10dB, bass is going to be insufficient for full-range home theater use. Running LFE through the mains will take 20dB beyond what they can deliver. IOW, even an unreasonable driver substitution is not going to get you the output you need - so you might as well just cross to a sub arround 40Hz 4th order (allowing for a maximum output of 106dB @ 40Hz). For music as long as the midrange can handle your loudness requirements the bass drivers will too. Conversely, if you need more at the bottom you'll need more at the top too.

Running the woofers in series is going to drop your maximum output by 6dB, which means you'll need to cross-over to your sub arround 50Hz if you want reference output levels for home theater use.

Obviously, different drivers are going to require cross-over changes w.r.t. the output levels, equalization, and perhaps the all-pass filters.


An externally hosted image should be here but it was not working when we last tested it.


My orion page
 
dayneger said:
A second question about amplification: would it be detrimental/problematic to hook up the 2 bass drivers in series? I've got a Nirvana'd 100W AKSA running my current 2 channel system. Adding 2x 55W AKSAs for the mids and tweets would probably be doable financially and space-wise in conjunction with my 100W for the two woofers, but 4x 55W AKSAs would break the bank. Or don't these speakers sound any better with amps like the AKSAs than with the chip amps?

Thanks for any inputs!

🙂 Dayne

Hi Dayne,

FYI, there is a post by at audiocircle about Orions powered by a stack of AKSAs. I provided one of the AKSAs and the buffered attenuator. A GK-1 was also used as an alternate to the buffered attenuator. See http://audiocircle.com/circles/viewtopic.php?t=7346

IMO, the Orions certainly have the resolution to highlight the difference in sound between amps. In fact, we were getting slightly grainy / fatiguing treble on a 55N, and this improved a little with a swap to another 55N. The 2nd unit was slightly tweaked (Auricap C1, schottky rectifiers, some minor component swaps), but the difference was audible.

One possibility to consider: a 55N on tweeter, the 100N on midrange, and TDA7294 chipamps, one for EACH woofer. Put generous p/s caps on the chipamp, they will need the stiffness in p/s. The rationale is that the sonic quality of AKSAs will come through most on the mid and treble.
 
Thanks a lot for the feedbacks!

I'm not quite sure how to interpret some of the responses--would it simply not be worth using DPL 12s since the increased output is almost never useful in normal stereo listening? Or that it would be positive, but still not enough for HT use?

I would definitely mount the 12ers so that the baffle width wouldn’t change--certainly don’t want to mess with the polar response etc. up top.

mb, we exchanged posts in that link you sent me, asking about whether the AKSA 100N could handle the 2.5 ohm dip in the paralleled Peerless XLS 10ers. Hugh’s response:

The Peerless at 2.5R would certainly rock the boat; since power is required here I'd suggest two, one per driver. That would be a walk in the park....

I like the idea of using 2 chip amps for the bass drivers and just adding one 55N (or N+ 🙂) for the tweeters. I think I read somewhere that the gain of the amps should be the same. Is that the case with the LM3886/TDA7294, or is this not a problem?

By the way, how did the GK-1 sound with them? I'm currently building a GK-1R. . .😎

Cheers,

Dayne
 
dayneger said:
Thanks a lot for the feedbacks!

I'm not quite sure how to interpret some of the responses--would it simply not be worth using DPL 12s since the increased output is almost never useful in normal stereo listening? Or that it would be positive, but still not enough for HT use?

As long as the single midrange meets your volume requirements I don't think DPL12s will help any for stereo listening. For HT they're not going to get you the 10 (no LFE) - 20 (with LFE) dB you need.
 
I use a pair of DPL12s in my dipoles and Drew is right that they won't give you huge HT bass, although mine are fine for normal music (inlcuding organ and reggae).

To get a lot more bass you would have modify the bass section of the Orion's considerably or add a monopole sub.

Steve
 
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