Bass Management

[Titanium Dome]

The recent animated discussion on the relative merits of the 2242 and 2245 (I have the near-indestructible 2242-HPL ) lead me in another direction.

Having had the chance to observe and benefit from the Synthesis® DACS calibration, I now know the extent to which correct use of this tool improves the overall performance of a great system. I've commented elsewhere about the significant leap such a process is from the now-typical one in receivers and pre/pros:

1. Set speaker size.
2. Set speaker distance.
3. Set speaker crossover points to sub(s).
4. Run SPL calibration either manually or automatically.
4. Boost or cut treble and bass.

And you're done.

Of course, even that process is a big step up from the stereo days when you had a balance control, plus bass, treble, and (maybe) mid controls.

There are more auto setup systems coming out, though most seem to require some human intervention to get everything right. Sometimes they just don't work well at all.

The biggest improvement I got from the Synthesis® calibration was in the LF. In fact, this is an area that vexed me over the years, since the bass can sound fantastic in one spot and be dreadfully inadequate in another, then be overly boomy and intrusive somewhere else. Using the midpoints of the front and rear walls for sub placement, a la the Harman Multisubs white paper, the DACS and its five mics found the right mix for the LF that turned every part of the room into a very good seat.

Since not everyone has or wants a Synthesis® system and calibration, the questions arise as to how the rest of our systems get close to the same great LF and what are the tools we use to get there? I'm aware of JBL's BASSQ™, the Velodyne SMS-1, and Audyssey Sub Equalizer.

Have any of you used these or others? They strike me as different products. I'm considering a BASSQ™ for my Performance Series, since the single-mic, auto calibration on my Outlaw 990 doesn't have what it takes to get it right. IMO :D

Your useful experience is appreciated. If you haven't done anything in this regard, opinions are welcome, too, though much less useful.

[rdgrimes]

The tool is not nearly as important as the mechanic using it. One needs to understand the tool, what it can and can not do and what things effect it's performance.

Seems to me like JBL's BassQ is intended for use in a system where effective bass management is not available in the AVR or processor. IMHO, the exact same results can be obtained in that situation with the level and crossover knobs on the sub(s). Locating and eliminating standing waves might benefit from an SPL meter.

I'm not familiar with the OutLaw's setup tools. Have used Yamaha's YPAO for a few years and am pretty happy with it. But I stick to a single sweet spot setup - to hell with the rest of the room as long as MY spot sounds right. :)

Ausyssey is extremely popular, but comes in different flavors in different units and performance seems about as varied as the people using it.

IMHO, bass management is a fairly small part of what's needed for total system setup, with EQ and level balancing being most important. But then I'm now accustomed to full-range speakers that don't need much bass tweaking.
Your PS system would be pretty comparable I'd think, room conditions outstanding.

[BMWCCA]

And what happens if it all goes out the window when you put on a poorly engineered CD tweaked to sound good in a hooptie in traffic, or going down your street late at night? Or a DVD movie soundtrack that overemphasizes what you so carefully EQ'd into flatness?

There seems to be little standardization in the creation of the source material, whether it's between labels, studios, or engineers. Everyone has an idea of the effects, compression, and levels they think makes it sound best—to their tired ears.

Now if you could just see that the original source was crafted to such demanding standards, and using the tools, you so artfully employed in setting up your HT. That would really be something. :)

Remember this from a thread a while back?:
http://www.rollingstone.com/news/story/17777619/the_death_of_high_fidelity/print

[rdgrimes]

Now if you could just see that the original source was crafted to such demanding standards, and using the tools, you so artfully employed in setting up your HT. That would really be something. :)

All that's required is some discrimination in your buying habits. There are ample examples of SACD, DVD-A and BD audio discs with stellar mixing and mastering, CD's too. High quality audio sources will always be hard to find, expensive and have limited depth of choice, but they are there.

[Rusnzha]

And what happens if it all goes out the window when you put on a poorly engineered CD tweaked to sound good in a hooptie in traffic, or going down your street late at night? Or a DVD movie soundtrack that overemphasizes what you so carefully EQ'd into flatness?.


I'm using an SMS-1 on my 2241 sub. When I set it for a flat response down to 20 hz, it sounded like crap. I left the peaks in and just lifted the 20 to 30 hz or so portion and it sounds awesome. This is really anal, but I set the bass level for each CD/DVD individually as each wants its own setting to sound best. I put a sticker on each disc with the level of the SMS-1 written on it so I don't have to figure it out each time. I turned down my subwoofer amp to give me smaller increments. The problem with digital stuff is that you don't have continuous variability like with analog. Sometimes I want to make that additional little tweak, but I like the results I'm getting doing this.

[Ducatista47]

All that's required is some discrimination in your buying habits. There are ample examples of SACD, DVD-A and BD audio discs with stellar mixing and mastering, CD's too. High quality audio sources will always be hard to find, expensive and have limited depth of choice, but they are there.

I can't argue with any of that, but that is a tail waging the dog scenario. When your system dictates what music you can successfully listen to on it, the music is no longer what really matters, your rig is.

When that happens it is time to get a rig that brings the best out in everything instead of being such a specialized system that you have to find the right music for it. The best sounding gear will make everything sound better than less capable equipment would. Lesser sources will sound like lesser sources, but they will sound their best.

Clark

[Mr. Widget]

Since not everyone has or wants a Synthesis® system and calibration, the questions arise as to how the rest of our systems get close to the same great LF and what are the tools we use to get there? I'm aware of JBL's BASSQ™, the Velodyne SMS-1, and Audyssey Sub Equalizer.I have a fair amount of experience with the Velodyne and Audyssey systems as well as the Room Correction portion of DEQX. I want to find out more about JBL's BASSQ. I haven't personally been involved in the JBL Synthesis room calibration process, but I am quite familiar with it and hope to experience it first hand in the not too distant future. :)

From a theoretical perspective the Audyssey system should be the best since it not only corrects for frequency anomalies at numerous points in the listening room, but it also corrects time related issues like group delay, phase, and other forms of time smear. That said, I do have an issue with the fact that they do not have a digital output in their outboard processors so you are stuck listening through their DAC... not much of an issue if the Audyssey you are using is built into your processor or AVR, but for a truly SOTA system I wish another DAC option was available.

From my actual experience using these devices I generally do prefer Audyssey, but then again at the moment I am using the Velodyne SMS-1 in my 2 channel system... as was mentioned in the mechanic comment, with all of these tools, the person setting it up will significantly affect the final outcome... Sometimes a new firmware or software version can also have a major effect. According to JBL, their latest computer calibration gear allows them to get the SDECs to do their best work. Basically they can get a JBL Synthesis system to sound better today than they could just six months ago... same system.


One thing I found interesting in TiDome's comments about the awesomeness of the bass of his Array system was that even though he is a self proclaimed bass head, he never mentioned the HT room curve sounding over powering for music listening. In my experience you want a good 6 to 10dB more LFE in an awesome home theater than you typically want for a similarly awesome music reproduction system. JBL's BASSQ system has the ability to store two separate room curves, one for music and one for films. This would be a welcomed feature in my system if I was going to use the same system for both applications.


Widget

[grumpy]

yet another h/w based sub-500Hz system (albeit studio-centric):

http://www.krksys.com/ergo/

based on "RoomPerfect" technology from these folks:

http://www.lyngdorf.com

Having experience in placing the mic, or mics in multiple locations with
any of these systems can make a significant impact on the end result
as well.

[Robh3606]

I have a dual purpose system for music and HT. When I run 2 channel any EQ is all analog. When I run HT the analog EQ stays in place and I can switch in Audyssey to EQ the complete system. For multichannel music I run without Audessey and for movies it's whatever sounds better. Sometimes it sounds better with Audyssey other times not. The main issue for running with or without is sound track dependent. I get a better sense of space without the Audyssey but location is more precise and the sound field is more homogenious with it on.

Bass management in in my prosessor which does a great job and is quite flexible.

Rob:)

[4313B]

When your system dictates what music you can successfully listen to on it, the music is no longer what really matters, your rig is.

When that happens it is time to get a rig that brings the best out in everything instead of being such a specialized system that you have to find the right music for it.Yep.

To be honest, most people who are into this audio crap care more about the rigs anyway... they might not admit it but that's the long and short of it.

[hjames]

I have a dual purpose system for music and HT. When I run 2 channel any EQ is all analog. When I run HT the analog EQ stays in place and I can switch in Audyssey to EQ the complete system. For multichannel music I run without Audessey and for movies it's whatever sounds better. Sometimes it sounds better with Audyssey other times not. The main issue for running with or without is sound track dependent. I get a better sense of space without the Audyssey but location is more precise and the sound field is more homogenious with it on.

Bass management in in my processor which does a great job and is quite flexible.

Rob:)

Interesting, Robh!
Can you talk a bit more about your gear in general ... The varying signal paths sounds quite useful!
Is it all specialized components or a mix?

[Mr. Widget]

Bass management in in my prosessor which does a great job and is quite flexible. Do you notice a change in the quality of the LFE when running Audyssey? In my experience it usually sounds more integrated and more taut... less boom, unless of course it is playing a big badda boom.;)


Widget

[Ducatista47]

Yep.

To be honest, most people who are into this audio crap care more about the rigs anyway... they might not admit it but that's the long and short of it.

Thanks for the backup. I felt the observation would be so wildly unpopular here that I did not feel much like posting it.

Time being a limited resource, more time spent designing/building/tweaking = less time listening to music. I would say that if more than five percent (being generous, I think most outside the audio hobbyist community would say 0.2 percent) of your stereo/surround time is spent on the rig, you would be an audio hobbyist at least as much as a music lover.

I remember a hilarious article in, I think, Popular Science, about 1959. It was a hifi enthusiast writing about how he attended a symphony performance and wanted to flee in dissatisfaction. He could not enjoy the music because he wanted to tweak the presence, adjust the volume, alter the bass level, etc. Since the dawn of high fidelity some have recognized that they have it bad. :rotfl:

Clark

[Robh3606]

Time being a limited resource, more time spent designing/building/tweaking = less time listening to music.

Not if you do both:D

Rob:)

[Mr. Widget]

I would say that if more than five percent (being generous, I think most outside the audio hobbyist community would say 0.2 percent) of your stereo/surround time is spent on the rig, you would be an audio hobbyist at least as much as a music lover.And being an audio hobbyist is less noble than being a music lover? Is being an amateur photographer somehow less relevant than being an art lover?

At times I have spent 100% of my free time building speakers at others I couldn't recall the names of the gear making the music play... it is all good.


Widget

[Robh3606]

Hello Widget


Do you notice a change in the quality of the LFE when running Audyssey? In my experience it usually sounds more integrated and more taut... less boom, unless of course it is playing a big badda boom.;)


Yes I do and your right the Audyssey does indeed tighten up the bass and make for a more uniform sound field. With the Integra implimentaion it also rolls off the highs a bit. In some of the sound fields you can turn the pre-emphasis off but not all. That's the rub for Music DVD's. I can either have a little bass bloom if the LFE is running or tolerate the HF roll-off. Usually I run without Audyssey on music and sometimes turn the LFE sub down a couple of Db depending on how prominent it is in the mix.

With movies it depends on the sound track. An example being I have more bass bloom in the sub 50hz region without it so for action movies it's a plus to run without. Works just like the added 6-10db you were talking about for subwoofer levels in HT vs. Music systems. That said some soundtracks can still be a bit bright so the HF rolloff can take the edge off and make it more enjoyable. It nice to be able to just do a quick A vs. B to see which sounds better.

I and I am very happy to have it available. It would be an even bigger plus if I didn't already have the analog EQ for the 3 front speakers.

Rob:)

[Valentin]

I find it very intelligent to try too fix an acoustical problem with an acoustical solution instead than with a purely physical or electronically way

the use of several subs(acoustical) with the help of some processor can really clean up the variance in bass freq for a larger area

please look at this presentation of harmans new reference listening room
some of the forum member know the place from the pictures

http://docs.google.com/present/view?id=dgkrf7p2_85fxbrc4d7

look at the graf of freq (page 15) of the 7 speakers at listening position
very impressive

and that room is not even close to be heavily treated

by the way many Harman person have gone from 4 center walls to 4 corner positions given the room gain and the use of the sound field algorithms

this method should be used in all professional studios and home studios it will be a lot cheaper than to build a non environmental room or all the other variations (fiscal solution)

[Valentin]

their are also some other alternatives for rectangular rooms
like the one presented in AES by Adrian celestinos which also uses 4 subs
but places them in the .25 and .75 part wide And .5 height of the front and back wall and aplais a delay to the back wall and out o phase signal producing a flat wave with excellent results for small room applications
another acoustical solution with a little help of electronics

[Robh3606]

Interesting, Robh!
Can you talk a bit more about your gear in general ... The varying signal paths sounds quite useful!
Is it all specialized components or a mix?

Hello Heather

Nothing special really. I have a Direct option in my Pre Processor an Integra 9.8 that keeps it all analog. My Left and Right speakers are an active 4 way set-up with EQ's for each channel. The center also has an analog EQ before the amp.

When I am running stereo obviously it's direct. When I run it HT mode I can run direct or with Audyssey. The bass management is straight forward. I have the mains as Full Range and the Center and Rears as Small. All my sources are Digital except for the 5.1 input for the Universal player one of the Denons. So everything except for SA-CD and DVDA are processed through the Pre-Pro DACS. I would like to get an OPPO so I can do SACD through an HDMI input. Would like to get a Blue-Ray as well down the road.

Rob:)

[Titanium Dome]

Sometimes a new firmware or software version can also have a major effect. According to JBL, their latest computer calibration gear allows them to get the SDECs to do their best work. Basically they can get a JBL Synthesis system to sound better today than they could just six months ago... same system.

I hope I got the newest version? :banghead: (Pretty sure I did. :D )



One thing I found interesting in TiDome's comments about the awesomeness of the bass of his Array system was that even though he is a self proclaimed bass head, he never mentioned the HT room curve sounding over powering for music listening. In my experience you want a good 6 to 10dB more LFE in an awesome home theater than you typically want for a similarly awesome music reproduction system. JBL's BASSQ system has the ability to store two separate room curves, one for music and one for films. This would be a welcomed feature in my system if I was going to use the same system for both applications.


Widget

The missing element might be what the SDP-5 contributes.

Since I use the Oppo BDP-83 for both DVD and CD playback, I just hit "Play DVD" on my Harmony 1000, and off we go. It took a little time to remember that the default for DVD play is Logic7 Film Mode. Of course, it sounded quite dynamic, but not what I wanted, so a push of the Music button brought out Logic7 Music.

The difference between the two modes (and their submodes) is significant. In addition, there are stereo, analog bypass, six- and seven-channel direct modes, etc. Each has a number of parameters that Chris gave me a brief tutorial on, so the room curve can be manipulated and saved as a favorite for future use.

The DACS calibration was done in a separate mode on the SDP-5, and I'm not savvy enough abut the whole thing yet to expound on it. (RTFM, Dome.) My impression is that the Logic7, DTS, Dolby, and other modes have some positive impact according to their purpose on the SDEC units. At least it was evident to me that the Logic7 Music Mode was what I wanted to hear when I listened to music, definitely not the film Mode.

[JBL 4645]

LFE crossover
http://en.wikipedia.org/wiki/LFE_Crossover (http://en.wikipedia.org/wiki/LFE_Crossover)

Low Frequency Effect
http://en.wikipedia.org/wiki/Low-frequency_effect (http://en.wikipedia.org/wiki/Low-frequency_effect)

U-571
http://en.wikipedia.org/wiki/U-571_(film) (http://en.wikipedia.org/wiki/U-571_(film))

All Bass Is Covered - Part 1
http://www.ambisonic.net/bassmgt1.html (http://www.ambisonic.net/bassmgt1.html)

All Bass Is Covered - Part 2
http://www.ambisonic.net/bassmgt2.html (http://www.ambisonic.net/bassmgt2.html)

Can you do any worse than this? Yes, you can. You can start messing with the lowpass to your sub (the one that’s still connected to the LFE with no bass management) so that it doesn’t cross over at, say, 80-120 Hz like Dolby suggests, or like the people have at home (because Dolby designed their system at some level) but at some other frequency. You can probably imagine the trouble this will cause, with the listener at home hearing holes or bumps in the frequency response – something entirely unlike what you intended.

What is the LFE channel?
http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/38_LFE.pdf (http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/38_LFE.pdf)

Dolby Multi-channel music mixing
http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/4_Multichannel_Music_Mixing.pdf

[Ducatista47]

And being an audio hobbyist is less noble than being a music lover? Is being an amateur photographer somehow less relevant than being an art lover?

At times I have spent 100% of my free time building speakers at others I couldn't recall the names of the gear making the music play... it is all good.
Widget

Not putting down anyone, it is all good. it was the semantics I was commenting on. Member after member agrees that "It is all about the music." But communities like ours stretch the comment a bit. To be a little crude, how many times can you shake it before it becomes pleasure? I may be as guilty of the construction/tweak act as anyone, but I don't think of it so much as fun, rather a time sucking procedure necessary to get the sound I want. Certainly not an end in itself.

Both are perfectly legitimate pursuits and neither is inferior to the other. I just like to see a spade called a spade. I personally happen to be of the Woody Allen school of results; he wishes the movies would just happen instead of taking all that time and effort to realize. That pesky work between the idea and the physical reality... So why don't I just pay someone else to do it? Because if you want something done just the way you want it to be done, you had better do it yourself.

I wish I could get to the point where I couldn't remember what was making the sound, but that will never be me. I was raised by an engineer and DIY enthusiast. It would be too big a leap.

So you are a better man than I am, Widget.

Cheers, Clark

[JBL 4645]

Both are perfectly legitimate pursuits and neither is inferior to the other. I just like to see a spade called a spade. I personally happen to be of the Woody Allen school of results; he wishes the movies would just happen instead of taking all that time and effort to realize. That pesky work between the idea and the physical reality... So why don't I just pay someone else to do it? Because if you want something done just the way you want it to be done, you had better do it yourself.

I wish I could get to the point where I couldn't remember what was making the sound, but that will never be me. I was raised by an engineer and DIY enthusiast. It would be too big a leap.

So you are a better man than I am, Widget.

Cheers, Clark

Well (Woody Allen) mixes or has all his films in monaural. Last one I saw was Bullets Over Broadway (1994) Odeon sceren 5 It was Dolby but only SR monaural.

The natural echo short reverberation made the sounds of the bullets fly over my head without vibrating my Broadway. It sucked! I want my money back! :D


Cinemas do it different if bass is going to LCR then a good portion of it will go there. Sub bass modules on the Dolby CP will extend it down though the use of sub bass extension that is mandatory for Dolby SR where the bass has lower high range.

Dolby SR-D or digital when used only uses the sub for LFE.1 track and only that track alone is used! The rest of the bass content is played though the LCRS. Same goes with 70mm thou the original operation was spread the bass in-between on the left-inner-centre and right-inner-centre channels.

I image that that has been since re-plugged so that the Baby Boom on format 42 goes to the arrays of sub bass speakers same deal with format 43 where it only has single sub bass track. Baby Boom played the same track over two channels, what waste of magnetic tape!

It was the spit-surrounds that took it into different direction thou many films where still be produced in format 42 only a few handful titles had split-surrounds.

You can read this information up and down the internet it more or less says the same story.

I tend to keep the LFE.1 playing on its own while sending the rest of the deeper lows off to the other sub and it, feels more natural.

Anyway I think the poor excuse for this is that, we home owners some of us have tiny speakers. This is true in most cases but I don’t see the need for Dolby to :bs: us because there are some who are suckers for a more exact like cinema presentation at home (since that has been the argument for decades now).