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Official Rythmik Audio Subwoofer thread - Page 8

post #211 of 15139
Quote:
Originally Posted by DonH50 View Post

They set the HPF at 80 Hz for the "upper" speakers and LPF at 80 Hz to the sub automatically for you ("it's a feature" -- especially with the lower-end receivers).

OK, that makes sense. IF that's how bass management works on those receivers, then LFE content from 80-120Hz would indeed be lost.

BTW, I was asking more out of curiosity than anything (my pre-pro has a dedicated LFE output that is separate from the L/R subwoofer outs).
post #212 of 15139
Quote:
Originally Posted by Rythmik View Post

Jim,

The answer should be "no". Google and one can find a few pages actually show the implementation of 5.1 channel "decoding" methods. The LFE sums with front channels first and then filters the subwoofer out again (www.beussery.com/pdf/beussery.dolby.pdf ). However, there have been quite a few AVR manufacturers adds nonstandard playback mode such as "LFE+main" in Denon 3805 I use. Also the terminology is not clear. One of the subwoofer modes in Denon is called "LFE", giving us the impression that the sub only plays LFE channel. Then when you go to the actual explanation, then it says :
"Selection of the "LFE" play mode will play the low frequency signal range of the channel selected with LARGE from that channel only. Therefore, the low frequency signal range that are played from the subwoofer channel are only the low frequency signal range of LFE and the channel specified as SMALL in the setup menu. That low frequency signal range is set up by crossover frequency point we select.

As being an engineer, an actual block diagram is an indisputable specification.

BTW, the reason it is called crossover because it actually uses Linktwitz-Riley filters (2nd order and 4th order) to separate out low frequency signals from a channel. It is just like regular electronic crossover method. In other words, if the crossover is 80hz, any signal between 80hz and 120hz in LFE will play back from front speakers. Nothing is lost.

In the above reference pdf file, the figures we should be interested is Figure 3-2 and 3-3. The former will cause lost of signal and the latter will not.

Figure 3-2 has done a lot of damage to understanding how bass management works. It's an authoritative source, so it's got to be right, right? Well, yes of course it reflects what Dolby implemented in their decoders at one time in the past, but modern AVRs (and probably even more recent Dolby decoders, perhaps) are more flexible. The standard diagram for how things used to work (and how a few AVRs, such as Marantz, still do) is one like your figure 3-2, called image002 below - note however, the crucial point that the summer is the last thing in the chain before the output, not the low-pass filter. This allows the full range of LFE to get to the sub, even though the rest of the channels send only stuff below 80 Hz.

Modern AVRs generally have crossovers settable by pairs, except for the center, so the second figure (subwoofersfigure5) more accurately describes how bass management works these days. Note the flexible architecture and clean design - and that the summation is again the final step before sub output. I like this figure a lot, since it clearly shows how simple bass management really is.
LL
LL
post #213 of 15139
Quote:
Originally Posted by fyzziks View Post

...it reflects what Dolby implemented in their decoders at one time in the past

Why didn't I think to check the date of the document? It's 10 years old (©2000)
post #214 of 15139
Quote:
Originally Posted by Bigred7078 View Post

just got my F12SE in yesterday Quick iPhone picture...


Oooh, sexy!
post #215 of 15139
@fyzziks -- Thanks for the update! However, almost all the AVRs I tested (ranging from 1 to 5 years old, Yamaha, Denon, and Sony) didn't allow enough flexibility in the filters. Yes, they did allow each pair to be set separately, but when I set the the main L/R crossover to 80 Hz, it set that frequency for both the mains (HPF) and the sub (LPF). It wasn't as much a problem of where the LPF was, but the fact that I couldn't set it and the mains HPF independently where I wanted. A higher end model I looked at this year (Pioneer Elite) allowed independent settings, so now maybe most AVRs allow that (i.e. independent settings and a more flexible crossover point)? Of course, that's also the main reason I have a new AVR on the way...

I have a newer Dolby paper at home (that includes 7.1) but not the latest (with the new TrueHD etc. formats) -- I need to grab some newer reference material.
post #216 of 15139
Don, almost every mid-range and up Denon that I have owned allows this independent selection of cross-over for speakers and LPF for LFE.

In my current config, I cross my mains at 60Hz and funnel everything below that to SW for music (LFE/LPF = 120) and I cross my mains at 80Hz and funnel everything below that for BD (LFE/LPF = 120).

That was one of the reasons I am very interested in the new PEQ amps on the F12SE. I don't want the big roll off at 100, with the older amp.
post #217 of 15139
Thanks Steve,

I'll check my Denon's manual when I get home (or later this week -- I have a rehearsal tonight and must travel on business tomorrow). It is a few years old (e.g. no HDMI) and that may be the problem. I am not using the sub output on my current AVR (Sony 3400ES) in my current setup, but I may go back to it as it will be easier to set up and manage the bass (though Magnepan argues against using the sub output). What you are describing is something I would like to be able to do. Maybe when my new (Pioneer SC-27) AVR arrives...

In any event, it seems the technology has moved forward rapidly so my comments are now invalid. IOW, I was wrong!

Thanks guys - Don
post #218 of 15139
Quote:
Originally Posted by DonH50 View Post

Hey Bigred, are you going to change to "Bigblack" now? Gorgeous sub, btw.

Aside: I was born and went to college in Columbia, MO -- small world! Still go back to visit the inlaws in Columbia and Fulton every year.

haha I could change it to that, but its a pretty small sub

Definately a small world! I'm actually going to school here at Mizzou, but i'll be moving in May after graduation to Charlotte, NC Thanks for the compliments.

Quote:
Originally Posted by lewdogg View Post

Oooh, sexy!

It definately is! The picture doesnt do it any justice
post #219 of 15139
Quote:
Originally Posted by lewdogg View Post

Oooh, sexy!

Yes indeed... if i do go with the rythmik i may spring for the se variety.

Quote:
Originally Posted by sdurani View Post

OK, that makes sense. IF that's how bass management works on those receivers, then LFE content from 80-120Hz would indeed be lost.

BTW, I was asking more out of curiosity than anything (my pre-pro has a dedicated LFE output that is separate from the L/R subwoofer outs).

Sorry, I don't understand.

"They set the HPF at 80 Hz for the "upper" speakers and LPF at 80 Hz to the sub automatically for you ("it's a feature" -- especially with the lower-end receivers)."

If hpf is at 80 and lpf also at 80.


wouldn't mains take care of everything above 80, and sub everything below 80?
post #220 of 15139
Brian,

I was reviewing the F12SE feature page and found this:


Crossover options

To suit different setups, we provide a 12 db and 24 db/octave crossover. If you are using sealed main speakers without any high pass filtering (speakers set to "small" on a receiver), then we recommend the 12 db/octave option. If your main speakers are vented, then the 24 db/octave option is best. If you use the small setting on your receiver for your mains, then we recommend the 24 db/octave option, whether they are sealed or vented. To understand more about how to correctly integrate your subwoofer, read our phase alignment article.


Seems like a mixed message, or am I reading it incorrectly?
post #221 of 15139
There seems to be alot of confusion about bass management and LFE when using an AVR.

This is how I understand it...and please correct me if I'm wrong...

Let's take a 3.1 example...

Say I set the fronts to 60Hz, and center to 80Hz crossover. High pass filters send the signal above 60Hz and 80Hz to the front main and center speakers, respectively. Bass below 60Hz and 80Hz in the front main and center channels are directed to the sub via the low pass filters.

LFE is a distinct channel which carries bass content separate from the other channels. It can contain bass content up to 120Hz.

So, when using an AVR with front and center speakers set to small, the sub receives the low pass filtered bass below 60Hz and 80Hz that is redirected away from the front main and center channels, AND the LFE channel which has bass content up to 120Hz.


My Denon 788 AVR allows for setting the LFE/LPF for the sub separately from the front and center crossovers. In my system, I set the LFE/LPF to 120Hz, and the crossovers for the fronts and center to 80Hz.

My Panasonic XR55 AVR, on the other hand, only allows for a single "universal" crossover setting. But, as I understand it....there still shouldn't be any info lost because the crossover redirects bass away from the speakers set to small...but shouldn't have any effect on the distinct LFE channel's content, correct?

Of course, if the subwoofer itself can't play up to 120Hz, or the crossover on the sub's plate amp is set to say 80Hz, then information from the LFE channel could be lost...
post #222 of 15139
Quote:
Originally Posted by fyzziks View Post

Modern AVRs generally have crossovers settable by pairs, except for the center, so the second figure (subwoofersfigure5) more accurately describes how bass management works these days. Note the flexible architecture and clean design - and that the summation is again the final step before sub output. I like this figure a lot, since it clearly shows how simple bass management really is.

The implementation of my Denon is closer than the Figure 3-3. The so-called optional 120hz LFE filtering is there. The LFE+main is there (ie, the LFE is duplicated via front left/right and sub to create a more spacious bass, haha). If we set the front speakers small, just stick a HPF right at the output of front speakers, instead of swapping between Figure 3-2 and 3-3. For any software/firmware/hardware designer, there is no point of devising two completely different schemes and switch between them (not to mention, it will introduce different latency and hard to compensate them so that all channels arrives at the same time). These flows are actually implemented in digital domain. In Figure 3-2, subwoofer is mandatory. Therefore this scheme is closer to systems with subwoofer built in such as Bose

BTW, we only look at the decoding side, how about encoding side? I bet the movie companies (actually the sound engineers) already figure out a way to encode it so that it decodes robustly across all different implementation. It is for their own interest to make it sound right.

[EDIT:] My denon can xover as low as 40hz. I wonder who would use that (or should I say who would design that) as he may lose the signal from 40hz to 120hz? That is almost two octaves !!
post #223 of 15139
Quote:
Originally Posted by alphaiii View Post

There seems to be alot of confusion about bass management and LFE when using an AVR.

This is how I understand it...and please correct me if I'm wrong...

Let's take a 3.1 example...

Say I set the fronts to 60Hz, and center to 80Hz crossover. High pass filters send the signal above 60Hz and 80Hz to the front main and center speakers, respectively. Bass below 60Hz and 80Hz in the front main and center channels are directed to the sub via the low pass filters.

LFE is a distinct channel which carries bass content separate from the other channels. It can contain bass content up to 120Hz.

So, when using an AVR with front and center speakers set to small, the sub receives the low pass filtered bass below 60Hz and 80Hz that is redirected away from the front main and center channels, AND the LFE channel which has bass content up to 120Hz.


My Denon 788 AVR allows for setting the LFE/LPF for the sub separately from the front and center crossovers. In my system, I set the LFE/LPF to 120Hz, and the crossovers for the fronts and center to 80Hz.

My Panasonic XR55 AVR, on the other hand, only allows for a single "universal" crossover setting. But, as I understand it....there still shouldn't be any info lost because the crossover redirects bass away from the speakers set to small...but shouldn't have any effect on the distinct LFE channel's content, correct?

Of course, if the subwoofer itself can't play up to 120Hz, or the crossover on the sub's plate amp is set to say 80Hz, then information from the LFE channel could be lost...

Yup - that's pretty much it Except that if the crossover (filter) on the SW is set to 80Hz, as you exampled, then not just the LFE information above 80Hz would be lost - any redirected bass from other channels, above 80Hz, would be lost.

The assumption on your Panny AVR may or may not be correct. Unless they specifically explain how the LFE channel is handled, the only way to know for sure would be by using LFE test tones.

The term "crossover" should never be used in context with LFE in an AVR. Sadly, most AVR documentation still refers to it in that manner.
post #224 of 15139
Quote:
Originally Posted by stevec325 View Post

Brian,

I was reviewing the F12SE feature page and found this:


Crossover options

To suit different setups, we provide a 12 db and 24 db/octave crossover. If you are using sealed main speakers without any high pass filtering (speakers set to "small" on a receiver), then we recommend the 12 db/octave option. If your main speakers are vented, then the 24 db/octave option is best. If you use the small setting on your receiver for your mains, then we recommend the 24 db/octave option, whether they are sealed or vented. To understand more about how to correctly integrate your subwoofer, read our phase alignment article.


Seems like a mixed message, or am I reading it incorrectly?

You are correct, it is mixed message. I need to correct that.
post #225 of 15139
Thanks Brian... if using small on AVR does it matter if the speakers are vented or not for using 12/24/db/octave? And which should be used?

BTW, days away from ordering the F12SE... still hoping you'll be able to advise a way to make the internal connections to force auto-on. Any thoughts? Doable?
post #226 of 15139
Quote:
Originally Posted by porksoda View Post

wouldn't mains take care of everything above 80, and sub everything below 80?

Not for the .1/LFE channel. When LFE is low passed at 80Hz, the rest of the content (from 80-120Hz) is usually not re-routed to the mains. Hence Brian pointing out a bass management scheme that combines the LFE channel with the main channels before low passing to the subwoofer. This way, the rest of the LFE content is already in the mains.
post #227 of 15139
Considering that some manufacturers don't follow the spec., I'd think it'd be best to determine what you're receiver/prepro is doing and work around it.
post #228 of 15139
Ok advice needed...

My setup integrates both a HT system and a 2-channel system. I have a pre-amp with HT bypass that I will be using (emotiva usp-1). The sub will be used for both music and HT.

Any ideas how to properly set up the sub for my needs?
post #229 of 15139
Quote:
Originally Posted by sdurani View Post

Not for the .1/LFE channel. When LFE is low passed at 80Hz, the rest of the content (from 80-120Hz) is usually not re-routed to the mains. Hence Brian pointing out a bass management scheme that combines the LFE channel with the main channels before low passing to the subwoofer. This way, the rest of the LFE content is already in the mains.

Ah i understand.

In my case.. i usually do all speakers small (i have full range towers). So depending on how bass management is handled i "may" lose freq above the xover from lfe channel only.

For stereo mode i have option of sub+sat or large+sub or large.

I will have to give a read over my manual.

and the manual says:

Cross-over Freq.: This setting defines the frequency at which bass redirection begins.
Frequencies below this level are redirected from ‘small’ speakers to the Fronts or to
the subwoofer; frequencies above this level are not redirected.
The value for this
setting depends on your speakers, environment and taste, and is best determined by
experimentation.
The adjustment can be made in increments of 10Hz between 40Hz and 130Hz.

So it kinda hints that lfe is NOT redirected to "large" speakers, so hence losing info above the xover.

So what brian initially said and what is recommended is to set l/r to large and everything else to small and use lfe. How would one know which method is being use for bass management for which manufacturer?
In a way it would be a hit n miss scheme no?
post #230 of 15139
Quote:
Originally Posted by Bigred7078 View Post

Ok advice needed...

My setup integrates both a HT system and a 2-channel system. I have a pre-amp with HT bypass that I will be using (emotiva usp-1). The sub will be used for both music and HT.

Any ideas how to properly set up the sub for my needs?


Good question, I'd love to see what Brian's take is on this since I'm in the same boat as Bigred and am seriously considering one of the Rythmik's subs.

The way I have mine setup is: in the AVR set mains to large, then preouts to the preamp, out to an external crossover (dbx223xl) from there on to the sub and amp. I have it crossed at 70 hz. My fronts are Monitor Audio GR20.

It seems that this has been working pretty well for me, except for I need a more "musical" sub. I care much more about music than movies...

Regards
Danny
post #231 of 15139
Bigred -- The emotiva web site has a PDF of the manual you can download. It has a good description of their bass management and how to use it. I would start by hooking the sub up using the emotiva's LPF function and the LFE input of the Rythmik, then use the HT bypass when running in HT mode (using the LFE management in the AVR). This assumes the LPF in the emotiva is better than that in the Rythmik, something Brian may be able to address. The advantage of doing it this way is that LFE is still handled by your AVR.

Danny -- FWIW (not much), I liked most of dbx's pro equipment, but in the past a lot of their gear was fairly noisy (N.B. times have changed and I have not listened recently). I know the old professional (600-series?) crossover I used briefly was OK, but the 2xx "consumer" unit was a disappointment. Your setup should work fine, I would think, and while I don't know what you have for a sub, I can say I was unprepared for how much better my system sounds with the new Rythmiks in place of my last sub (Infinity PSW212). My older sub was a custom servo design (long before everybody and their dog had one) and was very good in its day; I think the Rythmik is a better unit than that. Memory fades, but often tends to make things better than they were, so thinking the Rythmik is better than my custom job is a bit shocking and somewhat annoying since it was my design, but there you go...

ddtgr -- I measured the response of the outputs for a few AVRs and thought my findings had been obviated by newer receivers (see discussion above), but maybe not... Your experience sounds like what I found on some of my older units.
post #232 of 15139
Quote:
Originally Posted by DonH50 View Post

Bigred -- The emotiva web site has a PDF of the manual you can download. It has a good description of their bass management and how to use it. I would start by hooking the sub up using the emotiva's LPF function and the LFE input of the Rythmik, then use the HT bypass when running in HT mode (using the LFE management in the AVR). This assumes the LPF in the emotiva is better than that in the Rythmik, something Brian may be able to address. The advantage of doing it this way is that LFE is still handled by your AVR.

Yes I understand that. Im talking more about the actual subwoofer setup with both systems.
post #233 of 15139
Quote:
Originally Posted by Bigred7078 View Post

Yes I understand that. Im talking more about the actual subwoofer setup with both systems.

a while ago i had my avr and my integrated on the same system... for sub i used two sets of cable one out of integrated for stereo listening and when i had to switch to avr i would switch the cables at the sub for lfe.

my understanding in my avr was if ht bypassed for stereo then stereo was only audible though the speaker out of my integrated, and there was no signal out of avr's l/r. So i had to use the sub from my integrated.

When ht was not bypassed then avr's lfe and l/r were used.

---

you should confirm when ht is bypassed and you play 5.1 material if you get lfe signal.

also when ht is bypassed and you are listening to stereo if there is any info on lfe (depending on your speaker selection there maybe signal)

if answer is yes/yes then use the sub at lfe
if answer is yes/no then you may have to use two sets of cables for stereo sub and lfe setup.
post #234 of 15139
Quote:
Originally Posted by Bigred7078 View Post

Ok advice needed...

My setup integrates both a HT system and a 2-channel system. I have a pre-amp with HT bypass that I will be using (emotiva usp-1). The sub will be used for both music and HT.

Any ideas how to properly set up the sub for my needs?

Bigred

I have done this setup with both Proceed Pre and RSP-1 and preferred PRE since pushing a button led to unity gain...was not possible with RSP-1 since you have to swing the vol to 2/3 up and is a bit hit and miss.

I have always played the main speakers as full and taken the rca (xlr to amp) out of the preamp to sub l/r in...the trick has been using SMS to calibrate the system (I dont use it for eq but just to get realtime feedback to what I am doing to fr response etc)...I have been able to play with crossover, phase and volume on sub to blend it perfectly and address room issues alongwith mixing it with main speakers. The biggest surprise was how even volume on sub could induce peaks and nulls on fr! I use SMS to play with phase on lfe subs prior to running AUD Multi XT and gets me a far better way of integrating into my system...Just so you know have tried everything out there and ended up with this!
post #235 of 15139
Quote:
Originally Posted by Rythmik View Post

BTW, you guys keep coming up with new idea I cannot keep up with . I have in my hand FV15, TH, class D servo, ... not to mention I still owe Rick some answers about 8" or 10" servo... help!

You're going to need a clone or two to explore all of the product ideas
post #236 of 15139
Quote:
Originally Posted by porksoda View Post

How would one know which method is being use for bass management for which manufacturer? In a way it would be a hit n miss scheme no?

Yes, it would, since there is no standardization across the board. One way around it would be to do the old fashioned sub/sat configuration. Set your receiver to no subwoofer, small centre, small surrounds. All the low frequencies (including the discrete LFE channel) will end up in your large L/R speakers.

Run speaker wire from your receiver to the speaker inputs on the Rythmik sub, then out from the Rythmik to your front speakers. Dial in the subwoofer (using Level, Crossover and Delay/Phase knobs on the plate amp) to take over juuust where your L/R speakers naturally roll off. No part of the signal is lost and the Rythmik ends up handling the lowest frequencies of the entire system.
post #237 of 15139
DonH50,

l bought the dbx from a local store being almost sure I was going to bring it back, I even told the salesman that it might be the case. To my surprise, it has introduced no noise/artifacts as far as my ears can tell. I had to keep it.

I have an older Velodyne sub (CT150), and another benefit the crossover introduced was that it completely eliminated a slight hum in the sub. Before I got the dbx, I had it wired like Sanjay recommends above, which essentially uses the sub's internal crossover but in my case there was a ground loop somewhere which I could not find and the dbx took care of it. There is definitely something about using all balanced connections, I didn't believe in it before but now I'm sold. My next sub will definitely have balanced connections.

Regards,
Danny
post #238 of 15139
Bigred -- Sorry, must have misunderstood. I would set up the sub for music using the LPF in the emotiva and tweak everything in, then let the receiver handle it in HT bypass mode for HT. That would bypass the LPF in the subwoofer (though I think you give up phase control as well) and you set up the sub as for conventional audio system. When you go to HT, put the emotiva in bypass mode so it doesn't touch the analog signal passing through it, and let the AVR control basss management (for sub and mains, including LFE). If you are using you AVR as a (or the) primary source into your emotiva, you'll want to set the AVR in two-channel direct mode (or the equivalent) for music so it doesn't do any processing of the audio before the emotiva.

ddgtr -- That's great! I know some of their latest pro sound stuff is much better than in the "old days" so they must have brought everything up to snuff. (My early use was a stack of noise control units for various tape decks, though I am using a dbx EQ/processor at our church.) And yeah, after decades of doing live sound I can affirm balanced is a huge benefit. Too bad most AVRs (including every one I own ) don't have balanced I/O...
post #239 of 15139
Quote:
Originally Posted by DonH50 View Post

Bigred -- Sorry, must have misunderstood. I would set up the sub for music using the LPF in the emotiva and tweak everything in, then let the receiver handle it in HT bypass mode for HT. That would bypass the LPF in the subwoofer (though I think you give up phase control as well) and you set up the sub as for conventional audio system. When you go to HT, put the emotiva in bypass mode so it doesn't touch the analog signal passing through it, and let the AVR control basss management (for sub and mains, including LFE). If you are using you AVR as a (or the) primary source into your emotiva, you'll want to set the AVR in two-channel direct mode (or the equivalent) for music so it doesn't do any processing of the audio before the emotiva.

Thats kind of what I was thinking too. But I do not use my AVR for anything 2-channel Thats what the turntable is for going into the pre-amp
post #240 of 15139
Quote:
Originally Posted by Zmaximus View Post

Bigred

I have done this setup with both Proceed Pre and RSP-1 and preferred PRE since pushing a button led to unity gain...was not possible with RSP-1 since you have to swing the vol to 2/3 up and is a bit hit and miss.

I have always played the main speakers as full and taken the rca (xlr to amp) out of the preamp to sub l/r in...the trick has been using SMS to calibrate the system (I dont use it for eq but just to get realtime feedback to what I am doing to fr response etc)...I have been able to play with crossover, phase and volume on sub to blend it perfectly and address room issues alongwith mixing it with main speakers. The biggest surprise was how even volume on sub could induce peaks and nulls on fr! I use SMS to play with phase on lfe subs prior to running AUD Multi XT and gets me a far better way of integrating into my system...Just so you know have tried everything out there and ended up with this!

Well the RSP-1 was different since it did not have a true HT bypass. Fortunately for me the USP-1 does and I wont need to mark a matched gain level on the pre-amp.

I've thought about using a SMS-1, but I want to see If I can be happy without it for now. Thanks.
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