6 DIY eD A7S-650 kits with FP14K clone - Page 6

"LTD is basically claiming that all DACs are exactly the same and send an exact copy of the input signal to the output jacks..."

that is not what i said dave. i said "the dac conversion rates that modern gear run at do not degrade bass signals."

if the gear is rolling off your frequency response such that you can't get 2hz out of your system, that is a different matter.

analog gear can just as readily roll-off frequency response, but you know that.

It shows a bi-quad curve for a specific sub with +10dB of boost and alteration of the naked knee in a loopback measurement. One is using the Berry DCX, one is my SEQSS, one is the Marchand Bassis and one is the MiniDSP 2x8.

It's answering bass addict's Q. Yes, you can successfully use a shelf and several additional PEQ filters to get very close to a bi-quad, but I wanted to show that all of those solutions has a different roll off result. Many digital PEQ solutions have a roll off that eats into the shelf, so I didn't include those because the answer in those cases would be 'no'.

LTD,

My answer showing roll off variance was directed to bass addict and had nothing to do with my answer to your claim that all DACs are the same. There are variations in DAC architecture and the results have not been tested in the case of a subwoofer. The introduction of noise would be my 1st area of investigation. There is already nearly zero available information for below 20 Hz reproduction and absolute zero is the case for Delta Sigma converters, much less the rest of the components in a $300 do-it-all outboard digital EQ.

There are a huge majority who say that limiters are 100% transparent, the fact that they constantly and infinitely change FR is irrelevant and DSP is also transparent, especially so in the subwoofer passband. They also apparently agree that the values chosen for DC blocking caps is arbitrary and that that approach is 100% acceptable.

I believe I've done more research on the subject than anyone. My conclusion is that known and unchanging preset curves is better than limiter-induced infinitely and constantly changing curves and analog is the more transparent way to achieve the goal vs digital. I'm not going to say more than that (as I did in years past regarding everything else I was constantly put on trial for and had to slog through, over and over) because I don't have the time or the inclination. Folks believe what they want and like to hear what they want to hear anyway.

"the 10hz sine wave blew the theater doors open"

lol, mk, you are awesome.

nice frequency response and nice set of measurements.

What mic were you using there? When I was measuring at these levels, I was hitting the limits of my wm-61a. I was also nearing the edge of the power that the MA5050s could put out. I'd measure again after the FP14000 upgrades, but don't have any mics that can give me a good reading at these levels.

... first world problems ... I know.

Yep. 130dB at 10Hz messed up the seal on one of my doors to the patio. What are you calibrating your spl levels with MK?

Wow 130DB at 10hz?!

How do you know what spl level the tone being sent to the meter is? I guess that is my question is what signal are you referencing the spl to?

My ACO Pacific rig (7012 mic, 4012 pre, PS9200 power supply) is rated to 160dB, but I can't measure that high because the interface will clip, so it isn't the mic that dictates the max dBSPL.

What Josh is asking is what calibrates your rig. You answered that you use your RS meter to 106dB, but you have to be more specific. Do you place the RS meters cap at exactly the same spot to calibrate as your Berry mics cap when you measure and what frequency do you generate to read 106dB?

When you say sound bad, do you mean in terms of mechanical noise from the drivers (since 10hz is definitely the feel range)?

So you are able to HEAR the distortion at 10hz?

Damn dawg!
That is a sweet setup! Nothing like subs galore!

Ah I get it now! The distortion down low influences higher up. I've heard the effect before but never really thought about the root of it.

I can't testify as to whether James' subs can hit 130db at 10hz since he didn't do those sweeps when I was there. We just didn't have time. I did go there to see if I could detect ULF and how noticeable it is. I see why many who have the capability, Bosso, MK, NOT, Ricci etc, tout its effects on a movie and listening experience and why if you can, get a system that can reproduce the full soundtrack. We watched WotW and the lightning strikes that have content below 10hz when they run in the house wobbled the chair and my body pretty good. The LotR with the Balrog was equally impressive and noticeable. We did play Bass I Love You and the 7hz note was played clean and loud as well.

The funny thing is it's hard to describe the feeling for me. I've seen some say its like being under water. There is a pressure, but to me it just feels like my whole body is tingling and the air in the room is pressing in on me. Every time I felt it I recognized it was ULF. No it's not all the time of course, but I would definitely spend whatever I could to achieve that feeling in my theater.

To me a massive screen and being able to play at or close to reference makes the experience like being in a movie theater. To have subs that can play as low as these guys' systems just completes the effect. IOW I gotta have it.

Here's a short video my friend made while we were there. He's a pro, but unfortunately James has a dark theater and we dragged a lamp in there just to get any shots.

Sorry I took so long James.

http://vimeo.com/53050429

Whoa, great vid, however.... all it did was wet my appetite for more!

I didn't note the running time prior to viewing.


"I did go there to see if I could detect ULF and how noticeable it is. I see why many who have the capability, Bosso, MK, NOT, Ricci etc, tout its effects on a movie and listening experience and why if you can, get a system that can reproduce the full soundtrack."

"but I would definitely spend whatever I could to achieve that feeling in my theater."

"To have subs that can play as low as these guys' systems just completes the effect. IOW I gotta have it."

Yah sorry about that FOH. Eric wasn't too happy either. I guess until you see the video on the computer you can't get a good idea of how it'll look. He took plenty of video but it's pretty dark in there as James said. We'll probably head up again sometime and try to get some better footage. With James' consent of course.

Eric isn't that much into audio as much as me and after watching a couple demos he looked at me and said "you gotta get this". That summed it up for me. I really can't wait to enjoy movies that way, and he can't wait for me to get a system that HE can enjoy that way. James' screen goes from the floor to the ceiling too so the effect is just perfect. A screen that is matched by the sound.

I do wish we could've changed the HPF setting to see how dramatic the change is when a sub is filtered at different frequencies, but we barely had enough time to watch what we did. All I know is it just takes movies to another level and I'll spend a large chunk of my budget to obtain it.

Ahhh yes. The DR-250's. Man I love those speakers. I wish I had more depth in my room so I could put them behind the screen. Actually I *might* be able to if I can put all the subs up front. It could happen.

I really don't understand why in that speaker shootout they didn't like them. I have NEVER listened to movies that loud and only once did it bother me and that was LOTR in DTS at reference. That is insane loud. I also think that movie is recorded very hot. Every other movie clip sounded amazing at or above reference. Never once did Eric or I think it was too bright or harsh. They just sounded nuetral. I wonder if maybe the amp/electronics they were paired with made them sound bad because for us it was a pleasure to hear them.

What's crazy is James had two of them for each LCR channel. One is plenty. They handled every thing with ease and could've easily gone louder.

I would put them in my room in a heartbeat if they weren't 22" deep. They're bulky but that's the only negative I can think of.
Edited by Madaeel - 11/26/12 at 11:16pm

Something was wrong for sure, I couldn't even take the sound of those speakers at 30 under reference they were so painfully bright and I don't have a big sensitivity to supposedly "harsh" sounding speakers. We played with the eq but it didn't seem to matter. It would be great to be able to hear them in a treated room with the eq dialed in right. At our GTG they sounded like someone turned the eq up as high as possible between 2 and 4 khz, it was like a very sharp needle going into your brain.

There is NO way what you heard at MK's is what we heard in my room.

Awesome stuff guys, love that video - want to see more!