LS-9 tweaking and testing

Danny Richie · « **on:** 27 Jul 2007, 01:19 am »

I just thought I'd update you guys on the LS-9 progress.

I have the pair of prototypes up and playing right now. I still don't have the bases on them yet and the crossovers are externally clipped together on the floor behind the speakers. That mess of wiring behind them...

The crossover design was exactly what I thought it would be. The woofers and tweeters mate seamlessly. That was the easy part. I then spent a considerable amount of time tweaking the bass management system. I had to figure out how to best attenuate the range of gain and try to build as much flexibility into it as possible.

These things want to keep on playing in the lower ranges. It is really hard to tell just where it drops off. Right now I have the bottom end adjusted so that it is fairly flat in my room and it still leaves some room to pull more out of it if needed. I still have a rise from about 30Hz to 20Hz though that I don't think I will get out of it unless I plug the ports with foam plugs. Yes it is louder in the lowest range.

Since it is a little hot on the first half of the first octave, I have no idea where it's -3db down point might be in this room. My Clio only gives me measurements to 20Hz, and it is at least 5db up from flat at 20Hz. I sent it sign waves at 30Hz, 25Hz and 20Hz just to listen. It sounded like it got a little softer from 25Hz to 20Hz but I am pretty certain that is just my hearing dropping out. It still hit the room pretty hard at 20Hz, and the measurements confirm it. So I sent it an 18hz and a 16Hz signal and it sounding like it was hitting the room pretty hard there too. I'll have to get a SPL meter over here to see where it really falls off.

They certainly play lower than my dual SW-12A's with PR-12A's. In my room that sub starts rolling off some at 25Hz and is several db down by 20Hz. The LS-9's go way lower.

The real difference though is the speed and articulation of the bass response. These things will hit incredibly high output levels in the low ranges then immediately stop. It is easily some of the best bass response I have ever heard form any speaker or sub. And 24 6.5" woofers can really push some air. The Chinese percussion track from my Burmester 3 CD took on a new level of realism.

The longer line of tweeters had a nice smooth roll off into the lower ranges that put a natural crossover point at 850Hz. This is not much lower than the 1kHz crossover point on the LS-6's, but it sure made a difference. The LS-9's easily win out in detail level and resolution.

I think the deeper box may also be contributing to the woofers having a more transparent sound to them than the LS-6's too. They are really transparent especially for a large imposing speaker. I guess they are transparent as long as your eyes are closed.

Imaging is incredible and the sense of ease that these things have even when hitting big transient peaks is just amazing.

These speakers are going to be a lot of fun for a lot of people.

Bill Baker · « **Reply #1 on:** 27 Jul 2007, 01:45 am »

Geez, If I didn't loose my woodshop in the flood last year and actually had some free time, I would consider building a pair of these to have around for evaluation purposes. Very nice Danny.

Danny Richie · « **Reply #2 on:** 27 Jul 2007, 01:54 am »

Well, AV123 is offering them fully assembled and ready to play for a ridiculous price. So you don't have to cut a single piece of MDF if you don't want to. For me, building a set of enclosures is not a problem. Have the time to build a set of enclosures is a problem.

The kit price is only $2,695, but AV123's introductory price fully assembled was only $4,000. It maybe higher now. I don't know.

cujobob · « **Reply #3 on:** 27 Jul 2007, 02:34 am »

Whats the smallest size room you could see these working in, Danny?

Danny Richie · « **Reply #4 on:** 27 Jul 2007, 02:45 am »

I think that with the bass management system maxed out I might can squeeze them into the room at Rocky Mountain Audio Fest (13' by 19'). I don't think I'd squeeze them into anything smaller.

Any smaller of a room would require some agresive tube traps and room treatment.

There is always the LS-6's. That's not much of a let down. It is a killer good speaker too.

HAL · « **Reply #5 on:** 27 Jul 2007, 03:44 am »

Man, do I want to hear the LS-9's! aa

phoenix_rising · « **Reply #6 on:** 27 Jul 2007, 03:00 pm »

Quote from: Danny on 27 Jul 2007, 01:54 am

Well, AV123 is offering them fully assembled and ready to play for a ridiculous price. So you don't have to cut a single piece of MDF if you don't want to. For me, building a set of enclosures is not a problem. Have the time to build a set of enclosures is a problem.

Danny how does the bass on the LS9 compares to open baffle bass ?

Danny Richie · « **Reply #7 on:** 27 Jul 2007, 04:52 pm »

Quote

Danny how does the bass on the LS9 compares to open baffle bass ?

I'd say that the two are Apples and Oranges.

An open baffle bass system is clean because it minimizes room interaction (little or no room gain), and has no box colorations (no resonant boxes). However a lot of surface area is needed to hit any real SPL levels (even moderate levels) and this typically means several large and heavy cone (low FS) woofers. Stored energy and inertia is quite high due to the large heavy mass and noting but the suspension to control it.

The LS-9 woofers have low mass and don't have to move very far to hit a high level. So stored energy and inertia is quite low. The result is a very fast start/stop time. It is also capable of hitting extreme SPL levels with ease. The negative is that it can easy load a room with low frequency gain. This is the reason for the built in bass management system.

Buzz38 · « **Reply #8 on:** 27 Jul 2007, 05:23 pm »

From what I have read, these are meant for two channel, but for those of us with a dual need, do you have anything for a center? Also, are you saying the LS-9's can do HT without a sub? If so that makes these a bargain.

doug s. · « **Reply #9 on:** 27 Jul 2007, 05:54 pm »

any chance of designing &/or building these w/four cabinets? from what you're saying, it seems as if the woofers should be in towers not necessarily so close to the tweeters...

doug s.

Milehighguy · « **Reply #10 on:** 27 Jul 2007, 06:24 pm »

Here's a couple of ideas for using the ls-9 as a sub without the tweeters. Make the box shorter and put 6 drivers on the front and 6 on the rear, so as to cancel vibrations and make the height more convienient. Secondly, to solve the problem of too much 1st octave energy, make the cabinet sealed. Naturally the height, width and depth would be modified to get the right air volume.

Danny Richie · « **Reply #11 on:** 27 Jul 2007, 06:33 pm »

Guys, the woofers cross to the tweeters at 850Hz. They have to be right on the tweeters to blend with them and minimize any off axis issues. As is they have the same output over a wide range left or right of the on axis.

These are meant for two channel use but can easily be used for left and right mains in a home theater system too. I will work on a specific center later on. Some will be using another LS-6 or LS-9 as a center too, mounting it vertically just like the left and right speakers but behind an acoustically transparent screen.

And when you have a pair of speakers that blow away just about any sub out there it makes added a sub a little difficult to understand. I guess if you want to over drive a room with explosions then additional subs can be used.

Milehighguy · « **Reply #12 on:** 27 Jul 2007, 06:47 pm »

My idea of a sub wasn't intended to be used with the ls-9's, or as the woofer section of the ls-9's. I was just thinking of a seperate sub to be used with "whatever" satelite speakers, just as a general all purpose sub by itself.
Now it also occurs to me, that putting 3 woofers on each of 4 vertical sides of a sealed box might also work very well to cancel vibrations and break up room modes, and the sealed format would also solve the problem of too much low end energy.

Danny Richie · « **Reply #13 on:** 27 Jul 2007, 06:55 pm »

Jack. it was a post before you that mentioned putting them in a separate box.

Keep in mind that the low frequency output is already omni-directional.

These also need quite a bit of air space.

Any time you put a group of woofers in a line (like a line source) you get some collective low end gain where the group plays lower than possible with a single woofer. You can get this same effect with other drivers as well.

HChi · « **Reply #14 on:** 27 Jul 2007, 06:56 pm »

Quote from: Danny

...
I think the deeper box may also be contributing to the woofers having a more transparent sound to them than the LS-6's too. They are really transparent especially for a large imposing speaker. I guess they are transparent as long as your eyes are closed.
...

Danny, hypothetically speaking, if LS-6 box is as deep as LS-9, would its bass go lower and be more transparent? How much deeper could we expect/guesstimate?

Milehighguy · « **Reply #15 on:** 27 Jul 2007, 07:25 pm »

It sounds like the LS-9's have exceeded expectations. I heard the original Alpha LS at the first RMAF and was very impressed, and have been waiting for the next generation since then. To say I'm looking forward to hearing these at the next RMAF is an understatement. Danny, you better start working out and lifting weights so you can wrestle these monsters to Denver.

Danny Richie · « **Reply #16 on:** 27 Jul 2007, 07:33 pm »

Both the LS-6 and LS-9 have the same air space per driver.

If the LS-6 were made deeper and tuned lower it would add some extension and give up output in the lower ranges with a more gradual roll off. For some applications that wouldn't be a bad thing.

Any time you add depth to a box and move back wave reflections further back and give them more area to be absorbed then it can make a speaker sound more transparent.

How much depth to add to gain more in this area is like asking how much better can good get before it doesn't get any better.

Yea Jack, I may have to get me a tandem axle trailer this time.

mgalusha · « **Reply #17 on:** 27 Jul 2007, 07:49 pm »

Quote from: Danny on 27 Jul 2007, 07:33 pm

Yea Jack, I may have to get me a tandem axle trailer this time.

Then you'll have to borrow your buddies race truck to pull it with.

Buzz38 · « **Reply #18 on:** 27 Jul 2007, 08:01 pm »

Danny... You have BC dreaming of a sub out of these on the AV123 site. Could be pretty cool if it all dialed out.

BillB · « **Reply #19 on:** 27 Jul 2007, 11:24 pm »

Yes, I sure am dreaming and scheming.

These speakers behave very odd in a ported box though, they are pretty efficient considering.

I am thinking a sealed enclosure for these, 46l per 4, it has a high F3 but would still do over 90dB at 20hz before the room factors in...kinda interesting.

Do you think 46 watts a piece is a good number for them Danny? Though it would probably be less, they appear to be, what about 6ohm instead of 4?