Official Rythmik Audio Subwoofer thread - Page 273

Can someone help me interpret the graphs?? I can comprehend the common CEA2010 SPL vs Hz measurement graphs, where the dB axis goes from 0 to 120, and frequency axis goes from 0 to whatever. The graphs above have me perplexed. What does the -25dB and 0dB points on the X-axis correspond to in terms of actual dB SPL?? The following is a measurement graph for the Rythmik FV12, that has me wondering similarly. Help me understand these graphs in terms of SPL vs Hz on a 0 to ~120 dB scale. Thanks!

+1 thanks Bill!

Thanks for the reply. I don't think I've posted any of my settings, but either way, I've never turned the limiter off. I'm streaming the song from Spotify, but I'll try YouTube. I'll try matching your settings, too (although, off the top of my head, I think my settings might actually be the same as you -- even the 3db bump).

I have a test disc from Brian. I just need to find some free time when my two year old isn't asleep to mess with it. Unfortunately, it seems like the stars will align sooner than that actually happens

Ooops sorry, I was looking at Peen's settings. Hope we get this figured out.

No problem! Me too

After reading here the problems some people have had with MCACC settings I decided to go into my SC-35's menu and see what it set my FV15HP at, -12DB! I am a total novice but I bumped it up to -9DB and what a difference it made. I was already impressed at -12DB, now I am amazed.

I have the sub amp settings just like Rythmik recommends on the AVR section.

This post assumes that -12 is the maximum trim on the sub MCACC/your AVR supports which is how Audyssey works.

What happened was your subs gain was set to a level so high that when MCACC measured SPL it had to turn the sub down. When it turns it down to the max it likely means it actually wanted to turn it down even more. At this point sense we can't know how much more MCACC wanted to turn it down we do not know exactly how hot your sub is running. However it is running at least 3db hot and likely more than that. This is being considered calibrated to reference (at the comparable levels the director intended things to sound). That being said many, including myself, like to run the subs hot. I commonly run the subs 3db hot but I do so less often now with duals as they seem to provide more tactile feel for me. Other run hotter (6-8dbs). Also, with Audyssey anyway some feel it is important to keep your sub trim on the AVR within 3db of a 0 trim level so you have to adjust the gain knob on the sub to get pretty close. It's nice to have an SPL meter to double check any automated tools settings.

My recommendation is to adjust your gain on the sub down and re-run MCACC until you get with 3db of 0 on the AVR trim. Since your preference is to run the sub a bit hot You can do like I do and aim to have the trim after Audyssey around -3 so when I trim it up to run hot I am still within 3db of 0.

The Audyssey thread is filled with "where did my bass go" posts. Many are not accustomed to level/flat/calibrated sub levels. Usually they recommend trying it out for awhile to see if it grows on you. There's nothing wrong with preference and if you find you want your subs hot, trim it up. In the end it's all about what you like.

Noob Question. How you guys keep the kids away from the subs ?

dstew 100, running a sub to hot can damage the sub and bottom out the cone. You have a powerful sub and adjust the gain close to 0. Running 3db hot requires twice the power and is not that much louder. To double the loudness you need roughly 10 db. For example:
Using the same speaker specifications:

1 watt = 90dB

10 watts = 100dB

100watts = 110db

1000 watts= 120 db

I have a Pioneer and never exceed the MCACC settings by over 3-6 db on the sub on limit ocassions. I turn the sub up in the avr and leave the gain set on the sub one MCACC has adjusted things to reference level.
Edited by derrickdj1 - 2/4/13 at 4:23am

Adoption is always an option

I understand. I stay within the limits, keep the safeguards on, and run duals. I've gone to reference and my system stays clean there, but that's 1% of the time.

Have you tried mace?

Also, it's not the act of running the sub hot that that causes the possibility of damage. -10 on AVR with the sub at level/0 will put the same amount of strain on the sub as running at -13 on the AVR with sub 3db hot.

thats cruel, my suggestion at least provides the kid a chance of getting better parents

Seriously, i would just put some form of obstacles to prevent the kids from getting at the sub

@derrickdj1, here's a stab at my situation
watts, db
1, 90
2, 93
4, 96
8, 99
16, 102
32, 105
64, 108
128, 111
256, 114
512, 117
1024, 120

However, every doubling of this distance results in a 6dB drop in SPL. Not sure where you got that 90db measurement but I'll assume it is 90db@1meter. I don't see sensitivity on the Rythmik website for the FV15HP, is that the right number?
@6 feet, 114
@12 feet, 108
but I'm at 9 feet, about 111db
and I run duals (at least +3db), and I've got room gain, and my subs are close to the wall, and one of the subs is about 2 feet from a corner
I should measure but I should be right around the 115db LFE peaks of reference, note those are peaks, not avg level. Perhaps I'm a touch below and compression has started a tad by then.

Note the data-bass short term peak numbers for this sub stay below 120db at 2 meters with CEA outdoor ground plane testing
Edited by dstew100 - 2/4/13 at 6:34am

Have you guys installed room analyzing programs? The reason I ask, properly integrating a subwoofer system into a room's acoustics can raise your frequency curve by three to fifteen dB. That's a lot of free power with no additional stress on either driver or amplifier.

Graph; before graph is purple and the after graph is red.



Don't worry about the mid-bass dip as these are example graphs, highlighting my above comment about getting more energy from your subs into the room for one's listening pleasure.

Without a room analyzing program, nobody can see what's what with what regarding their integration efforts. Just saying.

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Edited by BeeMan458 - 2/4/13 at 6:29am

In addition to Audyssey XT32 I do run REW with a RS SPL meter. Haven't set it up since I picked up the second sub yet but it's on the shortlist. Considering one of the new USB mics too, prolly the Dayton.

When my daughter was young I was just consistent with her. I have B&W 805's on stands that are very prone to getting knocked over but it was never an issue. Sit and talk during the close calls and keep it clear that close to speakers is not the play area. Just being consistent was the key for me and never got to the point of time out or anything like that. It's amazing what a little communication can accomplish.

Allow me to encourage you to get your REW up and running as what it shows is "phenomenal." In my opinion, Audyssey XT32 or otherwise, anything else and the individual is guessing as the best out of XT32 is done when the best is already gotten out of one's integration efforts. In my opinion, XT32 is the polish to the raw efforts.

That second sub will create it's own maelstrom to confound your integration efforts. From personal experience, I've found that the addition of a second sub adds it's own foibles. When a second sub is added a null will be created and curing the null creates a dip, and raising the lower end drops the mid-bass end and every parametric change created their own particular equal and opposite reactions. Simply moving a sub one or two feet will create/cause more positive/negative changes but none is "visible" without the aid of a room analyzing program.

Sub integration efforts are, in my opinion, very vexing. Hence the overly repeated recommendation of including the use of a room analyzing program during integration efforts.

Roger that and tyty. I prolly wasn't clear. I've been using REW for about 8 months now and absolutely love it. For some strange reason the wife doesn't like the boom stand hanging over the sofa and wires running all around the walk ways so I do REW sessions, and then put everything away to keep happy wife happy life in check

I recently added the second sub and haven't run REW with it yet. I'm going to incorporate a minidsp and play with positioning when I do though (not that I have a lot of placement options). Since I was like a kid at the candy store when the second sub came in I just did the quick gain match, place equidistant, run XT32, minor distance tweaks with sine wave at crossover frequency and an SPL meter, and some integration sanity checks with the SPL meter. I'm pretty sure they are integrated decently right now, but know when I have the time I can take it up a notch with the insights REW provides.

I really need to do some room treatments but then we are back on the happy wife happy life issue. I may be able to get away with some panels on the front wall behind the mains though, just not sure how worth while that would be.

Rythmik posts content which is of interest to me.

Thanks for all the technical gouge. I wasn't understanding the excursion graphs from last week very well either so this recent one cleared it up a lot for me. I greatly appreciate you sharing this knowledge.

Brian, Out of curiosity, what are your mains?
Edited by dstew100 - 2/4/13 at 8:23am

.......

Gee. Funny. That's how things are at our place. A few days with REW up and running with a break of about two weeks or so and then REW up and running again. Like you, I'm currently in the REW on the shelf phase of our relationship. Next week I'll have cables all over the place with REW up and running again.


Good to read you're a REW fan. Room analyzing programs are a type of sonic religion with me: "I was blind and now I can see." "Everybody needs to convert." That sort of thing. But no room treatments on this end of the web as the wife will cry if I try to plaster her walls with room treatments.

(Ahhhh, come on honey, you'll get use to them.)

Not going happen.

You mentioned a minidsp. Is one better using a minidsp vs the Anti-Mode we have? I'm all for what works the best to tame those peaks. Currently I tune with REW and then run Anti-Mode and XT but I want better and I feel I can only get better with better. Don't got no XT32 and to get XT32, I'd have to replace a recently upgraded AVR.

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Edited by BeeMan458 - 2/4/13 at 7:28am

Concerning REW set up permissible length of time and treatments...
I present a well thought out, rationale position based on sound scientific principles for each of these issues. I define and clearly present the benefits that will be achieved, yet somehow I don't even get close to success against an irrational and frankly unreasonable position

Totally agree, I can't imagine not being able to measure the impact a change to my system actually made (now that I do measure). When I look back at me throwing hundreds and sometimes thousands at upgrades blindly it is just madness. REW rules. Fortunately I never bought into the cable craze that my dealer pushed hard. Isn't it awesome how today we can actually back up "I don't believe you" with real measurements we run on our own system and not just some claim that contradicts some other claim?

I don't think I'm strong enough with this stuff yet to say anything definitive but here are some thoughts which probably aren't anything you don't already know. Also I don't have direct experience with antimode, I've just read up on what it does and read many positive comments on it. I think since you have the antimode the difference XT32 would make, if any, is minimal. The XT32 advantage over XT is higher resolution filters on the sub, and you're already getting quality sub EQ.

Now on the minidsp vs antimode and audyssey technologies. Antimode and Audyssey are super automated and very easy to use. That's nice but unless you have the audyssey pro kit you really can't play with custom curves and manual EQ. That being said minidsp can do some really really complex things, beyond what I totally understand yet, and you can do totally manual EQ with it. It is an amazing little gadget with tons of kewl stuff (low pass, high pass, delays, crossovers, splitters/duplicators/multiplexers, more complex filters, boosters, attenuators, filter bandwidth controls, etc...). It's super Kewl, can be hard, can be awesome if done right, easy to screw up and do bad things, you know. It should be noted though that REW can suggest EQ filters for you, and with a minidsp REW can auto-configure the minidsp to apply them. How that compares to antimode and audyssey, ????????????????

The kewl thing is with REW we can measure what all these tools are doing. Not only in the final speaker output but you can run a loop through any of these devices and measure directly what it is doing to FR. I think we should be careful layering EQ on top of EQ, but with measuring, some trial and error, and patience we can get some great results.

What do you think?

Where do I sign up.

(It's all good honey, I just need this one more DSP. And the president would be proud of you letting me stimulate the economy in this fashion.)

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Edited by BeeMan458 - 2/4/13 at 9:10am

Those Avalon's are works of art. Do It, Do It. I wonder what those LCR's run for, they look very interesting to me. The higher end ones look amazing, I need to hear them some time.

I need to get something for imaging tests. Which Chesky CD do you recommend, it appears there are several. My imaging tests right now are very sophisticated. Do instruments sound like they are at different places between the speakers? Does my wife think the center channel is playing? Yup, good, lol. (Brian just cringed).

I've heard my 805s be criticized for poor off axis response so the imaging sweet spot is pretty small. Seems big enough for my seat

EDIT: BTW your post made me look up the tracks on the CD which in turn caused me to make a Jazz/Phil Woods pandora station. Thanks.

I play 'The bass I love' on YouTube via my Denon AirPlay and it sounds fine on my FV15hp (550W). I was playing at -10db volume with sub 6db hot. Really did not know what a single digit Hertz sound like (feel like I should say). Wow, lots of air movement like a big fan blowing at full speed. I have not seen the driver moving so much since owning this sub. I was a little scare to crank the volume up pass that. Just curious what instrument used to play that single digit note?

A suggestion, get uncompressed recorded material for demo purposes as the YouTube stuff is very compressed using lossy compression algorithms. YouTube recordings destroy the ability of any system to be evaluated. For evaluative purposes, just saying, YouTube recordings bad, uncompressed recordings played from a CD, good. The difference is night and day as to depth of image quality.