Author Topic: what's the best approach to have a +20dB rising house curve on subs?  (Read 1201 times)

Offline sevenz

  • Trade Count: (+16)
  • Full Member
  • Posts: 2440
  • home theatre lover :D
Need some help....

Currently I'm trying to use REW to generate a +20dB rising house curve (straight line slope) from 95hz to 25hz on the subs. Then port the file/ parameters to my DSP.

Assumptions:
- room EQ will be Audyssey.
- DSP is antimode DC.

Mains vol target (baseline) to integrate with subs >> Use 75dB here for discussion. ie. at 96hz onwards, it will start from 75dB.

Currently i know of the below approaches. Can help advise/ comment which is better? And if there are any other suggestions to do this best? =)

Method 1 (see screenshot below):
- Raising overall subs SPL such that at 25hz, the SPL is 20dB higher than mains. ie. 75dB(mains target)+20dB=95dB.
- then perform 'surgery' using REW house curve tool to cut the unwanted parts away.
- my experience is this takes away a lot of bass energy even though the FR looks swee


2) Method 2 (see screenshot below):
- keep subs SPL at 75dB same as mains, then apply PEQ to boost 25hz to +20db more than 95hz.
- FR line not straight never mind


3) Method 3 (hybrid method, see screenshot below):
- raise subs SPL by 10db only; and lower all speaker channels volume by 10db >> so that total still get 20db rise
- Raise subs' SPL such that at 25hz, the SPL is 10dB higher than mains. ie. 75dB(mains target)+10dB=85dB.
- then, reduce all the other channel levels by 10dB, such that overall, my SPL at 25hz is still 20dB higher than 95hz when playing.
- so mean when i watch movies, i now have to play at main volume that is 10dB higher than usual.


4) Method 4:
- Use Audyssey app to have an initial rising house curve first
- If not enough, then use Antimode to apply LIFT to reach a +20dB rising curve
« Last Edit: February 11, 2020, 16:41 by sevenz »

Offline desray

  • Global Moderator
  • Trade Count: (+4)
  • Full Member
  • *
  • Posts: 19748
  • Bring the "Cinema experience" back home...
Why did you want to do that?

Offline Boxerfan88

  • Trade Count: (+1)
  • Full Member
  • Posts: 1659
  • Life begins at 7000rpm
what's the best approach to have a +20dB rising house curve on subs?
« Reply #2 on: February 08, 2020, 12:47 »

3) Method 3 (hybrid method, see screenshot below):
- raise subs SPL by 10db only; and lower all speaker channels volume by 10db >> so that total still get 20db rise
- Raise subs' SPL such that at 20hz, the SPL is 10dB higher than mains. ie. 75dB(mains target)+10dB=85dB.
- then, reduce all the other channel levels by 10dB, such that overall, my SPL at 20hz is still 20dB higher than 100hz when playing.
- so mean when i watch movies, i now have to play at main volume that is 10dB higher than usual.


method 3

A conservative method to achieve your goal.
Reduce risk of clipping along the signal chain, with volume as the master control.

Sent from my iPhone using Tapatalk
« Last Edit: February 09, 2020, 16:43 by Boxerfan88 »
Soekris dac1541 | DA&T A38  | Usher MD2+X616 | Orisun DD12 | Samsung PS50B850 | Elementa BAC 2500 |
Yammy RXA3030 | RPi4+LibreElec | BDP-S5100 | PC+foobar2000 | Chromecast

Offline petetherock

  • Trade Count: (+8)
  • Full Member
  • Posts: 21989
  • Sidere Mens Eadem Mutato
    • My Music, Movie and Equipment Musings...
Have you booked a date with ENT ;)
Please post instead of sending a pm, so more can learn.

My gear:
http://peteswrite.blogspot.com/2019/04/my-setup-42019.html

Offline desray

  • Global Moderator
  • Trade Count: (+4)
  • Full Member
  • *
  • Posts: 19748
  • Bring the "Cinema experience" back home...
Have you booked a date with ENT ;)

LoL...

Offline ronildoq

  • Trade Count: (+2)
  • Full Member
  • Posts: 2419
Option 3 is a viable one

But you should first visit the purpose of boosting it +20db, can the dual 12” JL handle such a boost down Low?

Say u put in a high pass filter to protect the subs, things will be slightly more complicated , unless u have another big 18”  / 21” Monster subs for Low freq, they are best left untouched to roll off naturally. What follows is harmonic distortion when boosting past 20db

You may wanna try to limit the LFE instead, go to LPF for LFE and set this to 80hz, it will roll off earlier 80hz, doesn’t mean u will lose content. Then try not to boost too much

That way, your mains stereo bass will be much more balanced, but u still get your LFE feeling

Definitely revisit the purpose of boosting 20db

Last option, add more subs

Offline winwinc81

  • Trade Count: (0)
  • Full Member
  • Posts: 268
All is applicable with 3rd with slight advantage, but very impt point, is that cutting is more important than boosting, this is to prevent clipping. If either power amp or driver can't take boosting. Either one will fry.

Offline desray

  • Global Moderator
  • Trade Count: (+4)
  • Full Member
  • *
  • Posts: 19748
  • Bring the "Cinema experience" back home...
Option 3 is a viable one

But you should first visit the purpose of boosting it +20db, can the dual 12” JL handle such a boost down Low?

Say u put in a high pass filter to protect the subs, things will be slightly more complicated , unless u have another big 18”  / 21” Monster subs for Low freq, they are best left untouched to roll off naturally. What follows is harmonic distortion when boosting past 20db

You may wanna try to limit the LFE instead, go to LPF for LFE and set this to 80hz, it will roll off earlier 80hz, doesn’t mean u will lose content. Then try not to boost too much

That way, your mains stereo bass will be much more balanced, but u still get your LFE feeling

Definitely revisit the purpose of boosting 20db

Last option, add more subs

Precisely!

Offline desray

  • Global Moderator
  • Trade Count: (+4)
  • Full Member
  • *
  • Posts: 19748
  • Bring the "Cinema experience" back home...
All is applicable with 3rd with slight advantage, but very impt point, is that cutting is more important than boosting, this is to prevent clipping. If either power amp or driver can't take boosting. Either one will fry.

Precisely!

Offline sevenz

  • Trade Count: (+16)
  • Full Member
  • Posts: 2440
  • home theatre lover :D
method 3

A conservative method to achieve your goal.
Reduce risk of clipping along the signal chain, with volume as the master control.

Sent from my iPhone using Tapatalk

All is applicable with 3rd with slight advantage, but very impt point, is that cutting is more important than boosting, this is to prevent clipping. If either power amp or driver can't take boosting. Either one will fry.

Option 3 is a viable one

Thanks bros.

Yea wary about boosting. Will try to use cutting as much as possible.

One thing that bothers me about full cutting method is it takes away bass energy and energetic tactile feel. Winwinc - remember the difference u felt at my house when use the cutting method although FR looks perfect?

Trying to strike a balance kekeke
« Last Edit: February 10, 2020, 08:53 by sevenz »

Offline sevenz

  • Trade Count: (+16)
  • Full Member
  • Posts: 2440
  • home theatre lover :D
Purpose is to replicate something I recently heard that I loved and brought a smile to me :)

Offline sevenz

  • Trade Count: (+16)
  • Full Member
  • Posts: 2440
  • home theatre lover :D
Jag suggested another option.

First, use audy app to do whatever max rise the app allows on the sub channel. Then use antimode LIFT to settle the remaining rise needed. This way, the HC is first done within the room EQ filter itself. And minimise boosting.

Hope to have some good results on this.
« Last Edit: February 10, 2020, 10:11 by sevenz »

Offline ronildoq

  • Trade Count: (+2)
  • Full Member
  • Posts: 2419
A few other things u really got to zoom in other than the frequency response

Look at harmonic distortion as well. How much more distortion when +20db boost is applied, apart from compression test

Secondly, look at the timing response, how these filter Low pass high pass are affecting the frequencies

Finally look at the channel balance, stereo bass vs LFE bass, how is the transition with mains

These measurements will reveal lotsa information, the frequency response chart is just to let u know the tonal balance.

Harmonic Distortion and timing is far more critical that is highly audible

Offline ronildoq

  • Trade Count: (+2)
  • Full Member
  • Posts: 2419
Purpose is to replicate something I recently heard that I loved and brought a smile to me :)

This other sub u heard, was it also a JL 12” subs ? I would be surprised if it doesn’t go into distortion territory boosting +20db...

Unless played back at very Low volume levels , still 20db boost post eq is a lot, especially down lower frequency, quite massive

Offline sevenz

  • Trade Count: (+16)
  • Full Member
  • Posts: 2440
  • home theatre lover :D
Dual e112 subs.

Measured the thd. Depending on method, the highest thd ranges between 3-6% (20hz @ 95db) at ard 20hz area . Boost method gave it a slightly higher thd.

3-6% ok?

Offline sevenz

  • Trade Count: (+16)
  • Full Member
  • Posts: 2440
  • home theatre lover :D

Secondly, look at the timing response, how these filter Low pass high pass are affecting the frequencies

Finally look at the channel balance, stereo bass vs LFE bass, how is the transition with mains

These measurements will reveal lotsa information, the frequency response chart is just to let u know the tonal balance.   

U could be right

I suspect the hpf shifted the timing of the subs quite a bit. Cos after hpf applied, bad cancellation at the xover point with my centre.

Any recommendations how to fix bad cancellation at xover point...

Appreciated :)

« Last Edit: February 10, 2020, 14:30 by sevenz »

Offline ronildoq

  • Trade Count: (+2)
  • Full Member
  • Posts: 2419
U could be right

I suspect the hpf shifted the timing of the subs quite a bit. Cos after hpf applied, bad cancellation at the xover point with my centre.

Any recommendations how to fix bad cancellation at xover point...

Appreciated :)

Yea I thought so, too many filters messing things up. Ideally I would engage all filters first, meaning measure the raw response of each sub with the filters engaged. Once they are engaged, only then u proceed to align the impulse of the subs. After which, u align against the speakers woofer impulse, the first impulse from the speakers are the tweeters

Try this approach instead to blend in mains with subs.

No harm trying, nothing wrong. U will only gain more experience by trying. U can always revert to original settings if u don’t like it

Try and observe harmonic distortion as well, that’s the risk there of boosting too much

Nonetheless, aja aja fightin!

Offline desray

  • Global Moderator
  • Trade Count: (+4)
  • Full Member
  • *
  • Posts: 19748
  • Bring the "Cinema experience" back home...
Dual e112 subs.

Measured the thd. Depending on method, the highest thd ranges between 3-6% (20hz @ 95db) at ard 20hz area . Boost method gave it a slightly higher thd.

3-6% ok?

Sevenz, at who’s place you feel/hear the bass that makes you want to go for this approach? It’s interesting. I can dig deeper for my dual JL Audio as well but I chose to set around +6.0db so far to avoid any rattling to certain parts of my room/fixtures. The tactile effect will be “filled in” by the bass shakers with anything below 50Hz.

You have bass shakers right?



Sent from my iPhone using Tapatalk

Offline ronildoq

  • Trade Count: (+2)
  • Full Member
  • Posts: 2419
Dual e112 subs.

Measured the thd. Depending on method, the highest thd ranges between 3-6% (20hz @ 95db) at ard 20hz area . Boost method gave it a slightly higher thd.

3-6% ok?

3-6% is ok, as Long as below 10% good to go. But do check the playback levels. Assume it’s a +20db boost, that means when ur mains and centre measures 85db at -20 dbfs, and u play at MV-10 above reference, your subs are playing at +10db above reference . Unless u playback at -20mv, then your 12” subs are playing back at reference 115db for the LFE. Check the limits on the JL, can it handle 115db without distortion? The KK 12 I had in the past is good for 100db at 30hz, anything beyond and massive harmonic distortion kicks in. That’s why it’s only ideal for midbass. But I’m not sure on the JL. U gotta do the measurements to find out

Some movies are mastered extremely hot, u will have these peaks that surpass 125db at 20-30hz.... everytime u push the subs to its limits, that single DB rise will swing the entire harmonic distortion easily past 20-60% distortion levels

That’s why for subwoofers it’s good to have ample headroom, as it approaches demanding scenes, the LFE will be hot and will demand lotsa amplifier power

Ideally u want the subwoofers to be cruising, much more pleasant

The moment the subs are playing at its limits, the sound is very different . Just playback your mains without any XO, load in a simple 2 channel music, push your listening levels higher, observe how the speakers sound as u push the volume higher

Exact same thing for the subs

Offline ronildoq

  • Trade Count: (+2)
  • Full Member
  • Posts: 2419
3 options.

1. As mentioned by desray, use the subs for lower midbass and above, 30-40hz and above and actuators/ shakers for Low bass

2. Add on another 2 more subs to make it to 4, co locate them or stack

3. Change to a bigger 15” or 18” subs

As u were coming from a rythmik E15, u will miss the rumbles etc, the JL can give u that, but I suspect at lower levels. The difference between a bigger sized woofer and smaller one is the excursion and power also plays a part and the bigger woofers always have an edge in that it can playback effortlessly on demanding scenes, down lower frequencies

Unless Low bass is not the priority , then it’s ok

Then u will find big difference when you watch the movie “Ford vs Ferrari “, just won the Oscar 2020 for best sound editing . The engine roar from the cars...

That movie just reminded me why Low bass is a must, never mind the midbass, Low bass if done correctly, can be very satisfying . Especially for all the Hollywood movies , mostly focused on 20-30hz for the special effects

Offline sevenz

  • Trade Count: (+16)
  • Full Member
  • Posts: 2440
  • home theatre lover :D
Sevenz, at who’s place you feel/hear the bass that makes you want to go for this approach? It’s interesting. I can dig deeper for my dual JL Audio as well but I chose to set around +6.0db so far to avoid any rattling to certain parts of my room/fixtures. The tactile effect will be “filled in” by the bass shakers with anything below 50Hz.

You have bass shakers right?



Sent from my iPhone using Tapatalk

Ha my place la. :) Trying to replicate what I saw/heard on Dirac live. ;)

Hoping to get 80-90% near it for the subs' house curve and also the subs integration vs mains.

Yes I have shakers. Trying to get the best balance because shakers tend to make the tactile unnatural if played loud.

Using the dual e112 for low end to 25hz gives a more natural feel and has that low end room pressuring feel which the shakers can't give
« Last Edit: February 11, 2020, 16:38 by sevenz »

Online Tiktokape

  • Trade Count: (+9)
  • Full Member
  • Posts: 3309
  • Nothing to compare, be happy and enjoy while alive
Just because you are running NAD AVR with Dirac Live room correction does not necessarily means that your current subwoofers are capable to replicate your old subwoofers - specifications and sound signature still plays a part in it. On top of that, Dirac Live room correction is meant to aid one in tackling the room issues especially for an untreated room.

Offline ronildoq

  • Trade Count: (+2)
  • Full Member
  • Posts: 2419
Sevenz,
Here is an article on harmonic distortion, Hope that helps

https://www.audioholics.com/loudspeaker-design/audibility-of-distortion-at-bass/total-harmonic-distortion-thd

Using REW, Go with CEA-2010 burst tones to verify your distortion numbers when u dial in a steep +20db rising curve

+20db boost down to 20hz post eq is massive, that’s why u can’t find any settings on REW that allows that much boost. I’m guessing that the 12” JLs will be in distortion territory...it may not bottom like the kk. But could well be in distortion territory

Even on the seatons f18, I don’t dial past +8db. There are guides that an ideal number ranges from 4-10db. Most of the bunch settle at 8, including me. Heck even mark told me to use one that’s +4-6db... but I went with +8db

http://www.brentbutterworth.com/cea-2010-measurement-manual.html

Use this manual above from Brent Butterworth to do a CEA-2010 test for distortion . Zoom in to 20, 25hz and 31.5... I think the measurements will tell u immediately if it’s worth pursuing this route...

Any other JL E112 users here ? Able to share the limits on this sub and their distortion numbers ?

Offline sevenz

  • Trade Count: (+16)
  • Full Member
  • Posts: 2440
  • home theatre lover :D
Thanks Ronil. Understand on the distortion, will be careful on the very low frequencies. Trying to see if can reduce the rising by a few more dB yet not sacrificing the tactile. The natural curve of the dual E112 at my MLP has a 3-5db natural rise to 25hz.

Actually, u reminded me of 1 thing. Think i forgetful liao. I've been always using 25hz and 95hz for my E112 for the house curve. Slipped my mind. I'll stick to that instead of using 20hz-100hz.

Typically, I watch at main volume 65-74 on my marantz AVR depending on the source content. Like True Legend mid bass scene, i watch at about 74. Gravity at 65-69.

here's the data from databass.
https://data-bass.com/#/systems/5c12cb567f98c40004412ea6?_k=cfwk29

« Last Edit: February 11, 2020, 16:50 by sevenz »

Offline ronildoq

  • Trade Count: (+2)
  • Full Member
  • Posts: 2419


See this, I have the same experience, why I moved away from 12” subs and kept the 18” seatons . The above is coming from other members in avs. I prefer to read comments from users, rather than online paid reviews

Once u have experienced / owned a rythmik 15”, going back to JL 12”, this is what u will be missing.

This is precisely why I recommended u either move to a bigger sub or add more subs, for the tactile. Boosting like the above doesn’t really work, it only makes it worse with all sorts of distortion and headache when dialing in.

When it is too steep, the other problem u have and gotta ask is,

What if that particular sound track already has a built in house curve?

Say that sound track has been mastered with a +6db curve Low frequency rising, u will now have a +26db curve!  Then u start to grab that remote, lower the levels, and the next thing u find out, the centre channel dialogue sounds too soft.

Then u grab the remote adjust the centre channel levels.

In the end, u sell the centre channel speaker, thinking it is not good enough... then the cycle continues. Actually all the issue lies in dialing in a correct house curve for a good balance

Nonetheless, no harm trying and experimenting, u will be able to personally experience and understand your subs better