3ll3d00d

The overshoot on the upper end is handled by the very low slope shelf filter after it.

 

Had no idea JRiver couldn't support Slopes of more than 1.  Maybe a new beta release can if you ask the development team?

 

The correction differs some, but will help.  The correction will have some lumps in it from 10-30Hz, but should be decent.

 

Give it a try and report back.

 

JSS

ah right, yes I see what you mean

red is, I think, the sum of your LFE filter

cyan is using 2 LS with Q=0.707 plus 2 peaking filters; 1 at 17Hz, Q=1.5 and gain +5 & the other 12Hz Q=1.5 and gain +1

That would be great.  I learn better by seeing an example.

All of these are entered via the PEQ block in DSP studio. Note that if the PEQ block is before room correction then subwoofer means the LFE input channel, if the PEQ block is after room correction then subwoofer means the physical subwoofer output channel. You want the PEQ block to be *before* room correction. 

1. Gain -4dB

Click add/adjust volume

Enter -4

Select subwoofer from the channel dropdown

2. Low Shelf 15Hz, Q of 0.94, +6dB 

3. Low Shelf 15Hz, Q of 0.94, +6dB

As per the previous post, this is not directly supported in jriver so you have to approximate.

Click add/adjust low frequencies (low shelf filter)

Enter frequency 15

Bandwidth 1

Gain 6

Select subwoofer from the channel dropdown

Repeat

4. Peak 19Hz, Q of 2, +6dB

Click add/adjust low frequencies (low shelf filter)

You can now just repeat the same procedure for the next block, just choose the relevant LCR channels from the channel dropdown instead of subwoofer.

EDIT: see next post, the filters might need fine tuning for use with jriver.

 

LFE:

 

1. Gain -4dB

2. Low Shelf 15Hz, Q of 0.94, +6dB

3. Low Shelf 15Hz, Q of 0.94, +6dB

4. Peak 19Hz, Q of 2, +6dB

 

This is a v steep LS that has some overshoot at the top and bottom of the shelf isn't it? I guess this is because you wanted a steeper rise from the shelf?

A low shelf with this Q is not supported directly by jriver. It's low shelf is described in terms of Q but, as I understand it, it really mean S (shelf factor) and it limits this to a max of 1. The formula to convert Q to S is listed in http://www.musicdsp.org/files/Audio-EQ-Cookbook.txtand is

1/Q = sqrt((A + 1/A)*(1/S - 1) + 2)

where

A = 10^(dBgain/40)

If you solve for S you get 1/((((1/Q)^2-2)/(A+1/A))+1) which means you'd need jriver to accept a value of ~1.7 for the LS

If you go with a shelf with a S of 1 (roughly a Q of 0.707 in the minidsp terms) and increase the gain to 6.2dB then you get the following; black is your version, brown is what jriver can support. I suppose this is close enough?

OK. That. makes sense. Maybe some one can make a sticky on how to do this with Jriver, like there is a sticky when using that other device, if there are people who use Jriver. I just want to know that this can be done for individual movies. I would really like to try this so I can report back what I find.

Thanks

Will SpeakerPower make these available for purchase retail from the website?

 

JSS

they are already there aren't they? http://www.speakerpower.net/order.html

there is also http://www.speakerpower.net/dealers.html(I got mine from seaton)

Once I figure out how to do PvAs there will be plenty followed by spec graphs.

So I need the dvdhd and dts decoder?

you don't need the DTS decoder no, at least not if using a recent jriver as that's supported by LAV now.

you do need to be able to read BDs yes, I use anydvdhd. 

I can't find Mojave's tutorial.  I have my mad max bluray in my computer with jriver and speclab waiting.  What do I do?

post 8835 in http://www.avsforum.com/forum/113-subwoofers-bass-transducers/1333462-new-master-list-bass-movies-frequency-charts-295.html#post23468771

it is page 221 of 566 for me but avs forum software is rubbish so working out a direct link is always tricky, the above is using the default no of posts per page

Before doing that with Jriver, you need to extract the audio portion of the movie by either using MakeMKV or TSmuxer.

 

no you don't, you can do it direct from the disc or from a BD rip.

The XTZ 3x12 has some good reviews in the UK, especially at the c.£1600 pricepoint.

Yes, I have done that before but can I select something within spec lab from the input and output? 

go to File/Audio Files & Streams/ Analyse and Play File (with DSP) and choose the wav from the file dialog

remember to switch your mic cal filter to bypass

How do I graph the digital version to compare to my mic'd version?

One way is to use jriver to convert the track to a mono wav and then play that through speclab.

 

There should be a difference in levels of around 4dB going by the rating but I think the voltage out shows a bigger difference. I went to a voltage to voltage level calculator like this: http://www.sengpielaudio.com/calculator-db-volt.htm and when typing in the 2 peak voltages it shows a difference of almost 10dBV.

 

I guess I have no idea what the composite levels in dB are related to. Will someone please help me understand this?

I would think the difference will be that the composite rating considers the whole film not just the most aggressive scenes. I don't see that there would be any difference between a actual voltage based reading and one based on dBFS as long as both are clean and you use an equivalent reference for the max signal.

I verified it for Q of 1,2,3 and they look the same to me. The spreadsheet has a rather low resolution for higher Qs but it still looks accurate to me. 

I tested Qs 1,2,3,4,5,10 with +10dB gain at 60Hz, graph attached. I can share the mdat if anyone wants it.

FWIW I bought mine from seatonsound, it was both cheaper and ships with http://www.neutrik.com/en/audio/powercon/powercon-32-a/nac3fc-hc on the end of the power cable.

EDIT: actually now I reread my emails I see he said it normally comes with the powercon but he includes a terminated power cable, not clear from the above whether the connector is the problem or the cable. I suppose not such a big deal for us in the UK anyway.

is BEQ for Tron Legacy available? (you can guess who got this for xmas!)

No I didn't, I don't think my current sub could have managed that.

Not sure about the midrange problems you are experiencing.  Do you mean midrange or midbass?

 

I'll post up the BEQ correction for Guardians of the Galaxy tomorrow.  It is a substantial improvement.

 

 

JSS

I mean midrange, it just didn't seem v dynamic. Thinking about it, this could just be the change in spectral balance as the mains are both absolutely and relatively quieter.

I watched all of PR with the BEQ engaged and my house curve tonight, just a massive difference, quite mental bass. Really nice job done there. I think the mid range was quite bad though, not sure whether that is the track itself being a bit crap or the effect of applying such a strong boost to the low end.

I have my new sub turning up in the next week (2 * uxl 18) so will have to give it another go once that arrives. I guess I need to get Godzilla now too.

Keep up the good work anyway!

This pattern has nothing to do with a house curve being embedded in the mix.  To the extent that this may have been done, it is unlikely one can tell by looking at a PvA.  Instead, what you see in the PvA has more to do with the fact that loudness perception drops off rapidly with decreasing frequency in the sub bass range and also the fact that many natural broadband sounds exhibit an increase in level with decreasing frequency.  For example Brown Noise increases at 6 dB/octave as frequency decreases.  From 30-40 Hz to 130 Hz is about 2 octaves, so a 12 dB difference is, in fact, very reasonable to expect.

I'd forgotten about this thread - http://www.avsforum.com/forum/113-subwoofers-bass-transducers/1487271-spectrum-labs-different-slope-than-room-subwoofer-frequency-sweeps.html - which goes round the houses on this subject & seems somewhat inconclusive in the end.

I do not run a house curve (not enough headroom under 10Hz to do so), and I only try to get back what I feel was filtered...  It is very hard to explain, but after many attempts at doing this I can come up with a solution for a film in a few iterations without it sounding too bloated, unless the filters are very steep.  Then it is a little tougher.  

I took a look at an assortment of PvA graphs from the various films in the google docs spreadsheet and they invariably have the same pattern, a 10dB (+/- 5dB ish) rise from ~130Hz to 30-40Hz. This is a pretty good description of the shape of the typical house curve, if not a bit stronger than that. The Q to my mind is whether that house curve is actually embedded at mix time as opposed to needing to be added at home? 

Pacific Rim pre:

 

PR71.jpg

 

Pacific Rim BEQ:

 

PR71 BEQ.jpg

 

This one is SIGNIFICANTLY Improved. 

 

Pacific Rim is now near 5-Star with this correction, and from the opening scene with 'Axehead', you know it right away.  I highly recommend people try this one. 

 

I don't know how useful this feedback will be but I definitely concur with that "you know it right away comment". I only listened to that opening battle and it does indeed completely change the experience. In my room there is a fairly constant low level tactile sensation while the jaegar is strutting around and then some serious impact when things get going. 

One question though, do you run a house curve on top of this or is that baked into those settings?

You're welcome. I've had no problems implementing the BEQ filters in JRiver. Basically, I create a custom zone specifically for the movie I'm going to BEQ, and then create the filters for that movie in the custom zone. I then use ZoneSwitch to automatically switch to the custom zone whenever I play that movie.

Thanks man, that little blop down to 20hz and a little below right after the roll is what I was looking for. When I had the gratuitous LT going my space, that part was a little hotter than what I see in that graph but really provided a cool effect to say the least. I honestly like that part better than the roll itself

there is something that vibrates like crazy in my room at ~30Hz and so is lit up by that scene, it makes my head feel like it's buzzing which is quite an odd sensation!

it's the scene where it does a barrel role & the propeller blade comes off the one engine slamming into the side of the plane. I've never seen the rest of the film tbh so not sure if there are other bits like that.

How do I run the output of the amp to the line in?

I don't know exactly. I googled a bit more on this subject and it seems like it is more involved than I thought, for example http://www.diyaudio.com/forums/everything-else/127882-how-protect-sound-card-during-amp-measurements.html, so basically some sort of resistor network to provide a load to the amp and divide the voltage down to a reasonably level & then possible ground issues to deal with.