8x 18" LMS Ultra 5400s in 4 sealed enclosures - Page 6

I still think those Polk SRT's are cool. Pretty much the only Polk product I'd like to own. I remember drolling over those years ago.


Dude! Nice find.


Hell yeah! The explosion in the openning is awesome. Better yet is the .50cal machine gun mid way through the movie.

Stdgz,
I agree I normally listen 20 below, 15 max, anything higher is just not comfortable,dialog wise, I do run the subs hot though.

Very nice. You now have an image that matches your sound. I looked at a couple of used RS1's, but decided to buy new. I am picky about my image and send them off for repair (under warranty) for things that others ignore. I am as bad with projectors as some of you guys are with speakers and subs. I now have and use three projectors in my house. Two in the dedicated room and one in the family room.

To OPer.
You have subs that most of us can only dream about. Beautiful looking speakers and subs. Love the look of black uncovered drivers in black boxes. That is how my speakers and subs look.

I missed this. The Maelstroms were defective? What gives?

It is interesting that both distortion and and perceived SQ were improved albeit slightly. I wonder if it is inherent to the difference in drivers or the fact that the the LMS's are in a lower Q alignment given the same size enclosure. By my calcs, the LMSs should be around .56 Q whereas the MX's were around .68 Q.

I know eq was applied to both and the end results should be similar. I'm just curious if there are other nuances at play.

Nyt, do you get any rocking of the enclosures when playing 125db at 10hz? That should be significant excursion.

All in all, that is very impressive in a room that size.

Search is your friend.

I'll make it easy for you; as of right nowthe answer you seek is only 20 or so posts down from this one.

Wow! Three PJs. Initially, when searching last year, I looked hard at the Pro8100 - but lots of guys were having banding issues and would exchange 3,4,5+ units til they got a good one. Did Viewsonic address the QC issues, more recently?

OP, sorry for the tangent. Love the subs - would like to do something similar next year, although for budgetary reasons I'd spec the LMS-R 15" driver instead in my build, and probably only 4 of 'em.

Was that thunder I just heard or just the sound from notnyt's subs making its way to me on the south shore? In all seriousness I bet it feels good to be done with the build saga and to just be able to enjoy working subs.

Short rings gone.

This is great...

When the pre-post Audyssey FRs at the LP were posted, I used Ricci's GP FR and THD data to compose this approximation of how room gain reduces THD in-room.

I've been too busy to upload and post the graph and since then notnyt has posted the actual in-room 10 Hz THD data.

This is usually a very approximate exercise because room buzzing and rattling is an unknown, but it dispels the conventional wisdom that high GP THD below 20 Hz transfers to high THD in-room.

notnyt must have a very buzz/rattle free room. Nicely done.



I've done these calcs many times in my own room using Ilk's Tumult data and it never quite seemed to click with most folks, but it is simple physics and math and shows the value of the data from GP measurements exercises to real world expectations.

Now, if we had the 5-10 Hz GP data, we'd see same results or even lower in-room THD at 6-9 Hz, which is also what I've experienced with these calcs vs actual in-room measurements.

Again, awesome system. Over the years, I've gotten scads of comments like; "well, not everyone has 8-15s and tons of power", to which I reply, be patient, soon enough they will.

Bosso

Sorry, OT. I've had my Pro 8100 about 6 months now. I had banding issues, but installed a timer to "disconnect" it for 4 hours every night. That solved the problem. For $1200 this is an incredible PJ. Great lens. And I only paid $1245 for my lightly used 4622's! MK was my inspiration and like James, I LOVE a bargain!

An opinion I've suggested for years; the Inverse Square Law becomes irrelevant at 10 Hz in most rooms. At 110 feet long, the wave has reached the boundary limits and returned (even in your 50' space) before the driver has completed the cycle of a single 10 Hz wave.

This makes it impossible to radiate as the ISL dictates.

Look at the bump in response below 10 Hz (it only rolls off below that because the input signal and amps response roll off). As you change distance from the subs to mic, you should find that the bump stays at the same level, regardless of distance.

Bosso

Looks much better than most waterfalls I've seen. You're doing great!

Look very good, but usually I think you set the scale to around 45db and not a high 70db on your Y scale.

But looking at the slopes I suspect that there isnt much ringing past 300ms at all, which is very good.

Must sound awesome

It does look nice but I still wonder what scales are standard for doing those? It seems every other waterfall plot has a different scale.

Most of the banding problems are solved by removing power for a few hours every night by use of a timer. This projector has a great lens and throws a very nice image. I visited a guy that was using one in his room. Since I have a back up projector and could send in for repair or replacement, I decided to take a chance. I paid less than 1K for a new unit with 3yrs warranty. First year has express service. Viewsonic pays shipping both ways.

The measurements of notnyt's subs looks great. I think he is done with subs. I don't see anything that could be an improvement. Even power wise is not going to give him anything that he will be able to notice in real world use.

i have a Pro8100. it is freakin AWESOME , for the money. i have seen $5000 projectors that could not touch this unit.

Hey Notnyt,
How many cubic feet is that theater of yours ?

That is one impressive room. I can remember how odd the bass felt when i built my subs. I was so use to distortion. I was quite limited as far as my mains also, which you are NOT ! It caused a chain of events, like new mains, bass traps, sweeps,sweeps,sweeps galore....

They were set up and calibrated almost 8 years ago and i havent done a thing with them since....kinda sad when you build the best

Sealed subs rock !

bosso...i can't follow your plot in #162. which measurements go with which colors?

"An opinion I've suggested for years; the Inverse Square Law becomes irrelevant at 10 Hz in most rooms."

as you move into pressure vessel gain the inverse square law becomes irrelevant.

this happens at about 1/2 wavelength. for a reasonably well sealed room, that will occur at 1130 f/s / (h^2 x w^2 x l^2)^0.5 all divided by 2 where h, w, and l are in feet, or more simply
565 / (h^2 x w^2 x l^2)^0.5.

for most home rooms this is usually somewhere in the 20-30 hz ballpark, but may be lower in a really big room.

"Two enclosures on one amp, each on a channel at 2 ohms clip the amp 3db sooner than one amp on one enclosure, running each channel at 4ohms per driver."

can you restate? i'm not completely following. also, what are your test conditions? pink noise, sine sweep, test tones, something else? and...watch your power. i forget how you are wired in, but a 20 amp circuit can't haul more than about 2400 watts for any duration.

It's just Ricci's GP FR vs notnyt's in-room FR, from which you can use Ricci's THD data to anticipate the reduction of THD in-room and increase in dBSPL at 10 Hz.

The 3rd trace is just notnyt's FR after Audyssey.

When I first suggested the idea that the ISL ceased to apply in the PVG region, posters said I was confusing ISL with something else (I believe Seaton said something like that).

I posted this graph to illustrate:


1M vs 4M equals a drop of -12dB. My PVG begins in the low 20s Hz. This is back when I got comments that the low end was noise, HVAC, a truck passing by, etc.

Point is that every room will exhibit this phenomenon at some point going down in frequency. It's just that most measurement systems used are not accurate enough to show it.

Bosso

Agreed with Bosso here. This is akin to critical distance at higher frequencies. When you are very close you still have more direct sound vs. reverberant. When you get back far enough, you have more reflected energy arriving than direct. In large rooms with very directional speakers this can be a longer distance. In a small, home listening environment this is typically 2-10', and only at higher frequencies. The same situation is in place at VLF, but you then also have the modal variations, so levels can still vary.