[dpetey]

I like the tighter bass, Qtc of .7 or lower- I'd probably aim for .55-.06, even.  I realize there's a bazillion options, too.  It seems to me sealed would be best, for me anyway.  Two tower X 4 drivers would be huge no matter what you did; think how huge they'd have to be if they were ported!     The extra sensitivity wouldn't be a big issue anyway if you have a total of 8 drivers.

A pair of bass towers based on 4 X Shiva's or 4 X Tempests would certainly rock in a sealed type array.  I don't kno ...

If you have a room in which you can build an IB (you need an adjoining space), and you don't require your sub to move from place to place, an IB gives you the best of all worlds.  The bass is of very high quality, tight and quick, you can build it as big as you want to get as much output as desired, and the in-room footprint is non-existent since the sub lies outside the listening room.  Also, you don't need to put any kind of fancy finish on the manifold, nor do you have to worry about making the manifold any particular size or shape, or deal with porting issues.  IMO, if you meet the two criteria I mentioned above, an IB is THE way to go.

[Rob Babcock]

Yeah, that'd be nice, but my landlord might not care for it!   Unfortunately I don't own my house.  For the near future that probably won't change, so I'll need something a bit more portable.

[wshuff]

I read somewhere that the Neo8 has limited disperson vertically when mounted vertically. If you flip it on it's side, it would have limited horizontal dispersion, which seems to correlate with what you experienced, right? I was thinking along the lines of a horizontal center which had a four-faceted front, each facet facing a slightly different direction into the room, and each one having one woofer and one vertically mounted tweeter. I imagine it'd be quite a challenge to build a cabinet like that. At least, that was my thought...

I's been done.  Here's a pic.  A bit hard to see, but I thought it looked cool.

[Danny Richie]

Pros and cons to everything.

Let's take the Shiva for example (nice little woofer) and load it in a sealed box with a .6 Qtc as mentioned. That makes 2.9 cubic feet per woofer.

Then it is over 11db down at 20Hz and will require a transform circuit to keep it flat.

It will require a really large amp too because it will have to deliver 3 times as much power to the bottom end to keep it flat and still have any head room left.

There is a lot of added cost in transform circuits and larger amps too.

But the real bummer is that loaded this way it will have a limited acoustic output in the bottom end as it's power handling will go down.

By the numbers it looks like one Shiva loaded in a .6 Qts sealed box can only hit 94.8db at 20Hz before reaching its acoustical limits (mechanical in this case).

Now take our SW-12A used with the PR-12A.

It needs a smaller box of only 2.4 cubic feet and will reach a -3db down of 20Hz without added boosting (more amp head room). At 20Hz it is only limited thermally which is a limit of 116db.

I don't know how long it will last driven that hard but it is a lot longer than a Shiva in a sealed box.

I would also load each one in a separate enclosure, brace the crap out of it and load it with Blackhole 5. Killing the resonances is a big deal if shooting for good clean bottom end.

[dpetey]

I's been done.  Here's a pic.  A bit hard to see, but I thought it looked cool.

That looks pretty close, except I'd like to see the tweeters oriented vertically to reduce sound reflection from the ceiling.  I think the Neo8 radiates out from the sides more than it does to its top and bottom.

[ekovalsky]

Danny, would you mind posting specs for the PR-12A passive radiator here or on your website?  

The SW-12A models very nicely for sealed and ported/PR enclosures.  Looks like a real bargain at $99.

[Rob Babcock]

I'm not seeing the subs or passives on the GR site- what am I missing?

[ekovalsky]

I'm not seeing the subs or passives on the GR site- what am I missing?

Look for the menu bar at the top of the GR webpage, go to DRIVERS then NEW! Subwoofer/PR.

For some reason the bar doesn't show up in Firefox, use IE instead.  Or just click here.

Rob, six of these 12" subs/PRs built into a tall cabinet would be pretty killer, don't you think  

[Rob Babcock]

Ah, I see 'em.  Very cool!

[Danny Richie]

To model the PR set box volume to 2.4 cubic feet.

Set Vap to 6 cubic feet.

Set Fs to 12.2Hz.

Updating and re-designing the web site is on the list. So hopefully everything will be more user friendly soon.

[Danny Richie]

To model the PR set box volume to 2.4 cubic feet.

Set Vap to 6 cubic feet.

Set Fs to 12.2Hz.

Updating and re-designing the web site is on the list. So hopefully everything will be more user friendly soon.

[ekovalsky]

To model the PR set box volume to 2.4 cubic feet.

Set Vap to 6 cubic feet.

Set Fs to 12.2Hz.

Updating and re-designing the web site is on the list. So hopefully everything will be more user friendly soon.

Is the PR a slightly higher Fs version of the Peerless XLS 830548 ?  I needed to input a Qms value to avoid errors with WinISD Pro, so I used 15.2.

I can create a model flat to 20hz but only with a bigger box, about 4 ft3.  With a 2.4 ft3 box the models shows down 8dB at 20hz.  Of course with room gain in small to medium sized enclosed spaces, that may well boost output flat to 20hz with the smaller 2.4 ft3 box.

Equalization definitely will limit power handling and headroom, but sealed enclosures are nice in that one can take control over the transform function in the bottom octave if desired.  With vented/PR design is that the output below the bass cutoff falls so fast it is impossible to equalize.  Obviously when properly implemented so the cutoff is in the low-mid 20's or upper teens this isn't really an issue
 

[Danny Richie]

Is the PR a slightly higher Fs version of the Peerless XLS 830548 ?

Actually that one is 12.6Hz Fs. Ours is 12.2Hz Fs and fully adjustable.

I can create a model flat to 20hz but only with a bigger box, about 4 ft3.

In 2.4 cubic feet it is flat to about 25Hz and -3db at 20.8Hz according to Bass Box.



My impedance sweeps confirm the tuning frequency as well.

With a 2.4 ft3 box the models shows down 8dB at 20hz.

You've got an error somewhere there in your figures.

I have also measured the output and have found it not to fall off at all until after 25Hz. One other company using these showed the same in their measurements and held one woofer to 106db in room response that didn't drop off until 22Hz. Of coarse there is some room gain in those numbers.

Try this amp: http://www.apexjr.com/Apexsenior.htm

Bass Boost mods are as follows: R-26 is a 18K resistor by changing to a 47K you'll get a corner freq of 18Hz with a 2Db boost at 21-22Hz.

This makes it pretty much flat.

You can also power two woofers off of one of these amps. We measured this amp to actually output 400 watts into 4 ohms.

It is not expensive either.  

[klh]

Danny,

Can you update the progress of the new line array? What would the frequency response of the array be with a sealed box? Lastly, please describe the new Neo 8's (how they differ from the ones in the previous line array and what their measured anechoic frequency response is... that is how high they go). I'm particularly concerned with the high end extension as the previous Neo 8s were known for having some difficulty in that area. If you can, please back it up with graphs. Thanks a lot and keep up the good work. Oh yeah, I'm also interested in setting up an infinite baffle subwoofer, so integration with the speakers is critical; that's why I'm interested in the frequency response of the mids in a sealed enclosure. Sorry, one more question... what do you plan on doing in terms of the center channel? Have you thought of doing one like Azryan did? Thanks again!

[Danny Richie]

Can you update the progress of the new line array?

It is being delayed a little at this time to incorporate one more improvement to take it one step further. I am having the Adire XBL^ motor structure technology added to the woofers.

What would the frequency response of the array be with a sealed box?

Right now the -3db down point in a sealed box will be in the 55Hz range without room gain, but with the XBL^ added to the motor this could be lower.

Lastly, please describe the new Neo 8's (how they differ from the ones in the previous line array and what their measured anechoic frequency response is... that is how high they go).

The new ones are of the PDR type and will be 8 ohms each. They will play to 40kHz and have a much smoother top end than the previous version.

I'm particularly concerned with the high end extension as the previous Neo 8s were known for having some difficulty in that area.

Yea, the previous Neo 8's used in the Alpha LS dropped off some after 16kHz and was about 4db down at 20kHz then flattened out and extended to 40kHz. Pretty hard to hear actually, but the newer version is not the same.

If you can, please back it up with graphs.

When it is time for release all measurements will be made available, just like all of our kits.

what do you plan on doing in terms of the center channel? Have you thought of doing one like Azryan did?

I have a couple of options that I am looking at trying right now, but would rather not let the cat out of the bag just yet.

[klh]

That was a damn quick response! That smooth 40kHz extension is exactly what I was looking for. Great to hear you're implementing the XBL^2 technology. Since you have to pay to get it, I hope the prices don't  increase too much. Please keep us up to date as time and advances permit.

[wshuff]

A question about the new LS designs.  Do you plan to stock cabinets from MLS like you did with the Alphas?  That ebony looked really nice.

[Danny Richie]

Oh, I have a pretty good feeling that something like that will be made available, and that MLS will be involved.  

[wshuff]

Oh, you're an evil fellow with your green smiley face.  Don't keep us waiting too long...

[sonicboom]

Danny,

I Haven't seen any news on the progress of the LS-9/LS-6 lately. What's the good word?  Hope everything is coming along OK!