Another Erskine-designed masterpiece (if I don't screw it up). - Page 5

Make one louder to start, problem is every seating position is different. What you end up with is something that is the result of a weighted averaging process.

Ha, tell me about it. After demoing a couple walls, the drywall piled up enough for me to stand on top and rip down the ceiling, LOL!

If you have 70 dB at 3 feet from a speaker, at 6 feet you have 64 dB, at 12 feet you have 58 db. With a surround speaker (or LCR for that matter), you end up with a significant difference between the seats as you move across the seats in a row. To reduce this effect, you increase the distance between speakers and the ears so the percentage of the difference in distance between speakers and seats is minimized. This is very problematic in small rooms (residential sized spaces). Where you have a small room, with say, two rows of seats, the back row very near the back wall and the front speakers at ear level, in effect, any money you spent on seating for the back row is wasted (get a better projector).

The above is an over simplification to the extent the rate of decay over distance varies with frequency as well.

So now, back to our regularily scheduled program and let Kris proceed with his room without ulcer generating FUD.

fyi -
the inverse square law is only applicable in the absence of reflections or reverb.

That was the famous Richard Clark technique, right? Or maybe he was just an ardent practitioner.


I have found other autosound "tricks" work for the surrounds, too, even with conventional drivers. Aside from positioning the surrounds above the listeners, which increases the path length to the nearest seats as Richard mentioned, try aiming the direct axis of the speakers toward the furthest seats in the room (from that speaker). It helps reduce both the level and the spectral difference for the overall audience. The closer you sit, the more off-axis.

Line arrays are also a good way to mitigate the distance falloff effect. Toole discusses this in detail in chapter 16.4.4 of his Sound Reproduction book.

Fortunately, there's really no need to respond to posts like these.


I believe that this should work even better with speakers with more controlled directivity?


Do you have any suggestions to matching the line array surrounds to the front speakers, or do you suggest the use of line array LCRs?

KBlaw2010, the build looks amazing. I'm really enjoying reading and seeing your updates. I hope you'll be able to post some measurement data after you're done!

[quote=Roger Dressler;21051185]That was the famous Richard Clark technique, right? Or maybe he was just an ardent practitioner.
QUOTE]

Congratulations! Bingo! Clark's show winning Buick Grand National with the ugly graphics. Really the first to use compression drivers. He mounted a standard pair of tweaters in the doors and covered the horn mouths with grill cloth to keep his secret weapon secret. Lost touch with the car audio stuff, but don't think they are using horns any more. Coaxing a decent frequency response out of those early drivers was brutal.

Oops. Sorry. Off topic. Hey, nice theater.

I agree. Smooth off-axis response is very desirable. One particular concept, the concentric tweeter/midrange as in KEF or Tannoy might work well for surrounds as they have smooth off axis response both horizontally and vertically.


I feel line arrays are not necessary for the fronts since in typical theaters the distances are much longer to the LCR than the surrounds.

That's more like it, I knew the (2) P10's, had to be a typo. Two double 18's is getting closer

Great design, nice build, you're going to have a very nice room. congrats on all the progress to date.




I listened to some of 12" Tannoys recently, set up as mains. I really did enjoy what they had to offer. I think I'd prefer smaller diameter LF drive unit, if I were using them as surrounds, little less beamy as low as possible. Anyway, I hadn't seen anyone mention Tannoy much, and these were install series, mated with LabGruppen power,....quite the combo. They're doing something right, the MF/HF was wonderfully easy to listen to, even at killer live levels. Regarding coaxials, they've been at it for a long, long time.


Thanks

(subscribed) looks good so far

Glad to help. With the previous spec, (4)10"s for that many cubes just wasn't going to cut it for subwoofer duty. You had much more displacement above the crossover, than below. I don't think you're going to regret the increase in capability in that room.

I spent some time with Gerben, discussing several aspects of Procella's line while at CEDIA. Amidst the very hectic atmosphere, he was generous with his time. I enjoyed their room, however most of all, I was pleasantly surprised to see the internal amplifiers on the subwoofers were made by Powersoft. Powersoft, somewhat of a phenom in amplifiers with incredible products that pack record amounts of high quality, bullet proof dsp contoured power into extremely small units. Their K20 is truly an incredible piece in the world of pro audio. 18,000 watts into 4 ohms from a single rack space

I'm looking forward to seeing the continued progress of the space, I'm sure as move in time nears, things will get quite exciting. Again, I really like the design, especially the sidewall config/angles, nice. It's all about the room, and it appears you're in great hands. I only wish I was in a position to begin a new build. Exciting stuff.

Good luck

Hello, looking at your pictures, can you tell me where I can find that cooling unit? Thank you.

The boot print is an excellent added touch. LOL

What are the speaker backer boxes for?

Did the rotozip get away from you? That happened to me more than I care to admit! I finally went to using the handsaw because I could not figure that thing out.

Room is looking good.

Really like the tiered lines, nice,....coming together.

Continued good luck

Looking good. Where did you get that intake diffuser? Been looking for one like that.

Thanks.

That tiered look is really going to be sharp - Looking forward to much more !

THe drywall crew must really hate you.

Lookin great!

Are those nailor diffusers for hvac or bass trapping?

Looking really good. Can't wait to see more (hint hint ...).

Couldn't see it mentioned in your thread, but what is your ceiling height ??

I'm picking around 11'-12' and each tier is about an 8" drop ??