Bass Management...what's a person to do?

[Andrew Pratt]

There seems to be a lot of talk lately on what bass management should or should not be doing. It also seems that there are a lot of assumptions being made about what, where and how this BM should be invoked. I came across a few links that are interesting and suggest that the problem isn't with X but with Y or Z etc....food for thought.

Soundpro's discussion

Polks discussion

And here's what Rotel has to say about their processors and the way they do BM

The Mystery of Bass Management

Bass Management is a subject that even the best music engineers don't always seem to know a whole lot about, and is easily misunderstood or simply missed.

The majority of music discs prepared for playback using DVD-A and SACD do not have a LFE point-one track. The rule in the studio is if you are mixing music don't put anything in the point-one track. This extrapolates to assuming that the user will be using five full range loudspeakers or equivalent.

Today's 5.1 systems have developed from surround audio configurations originally designed for movie theater applications, and they bring with them a number of oddities some of which are not particularly appropriate either for modern digital audio distribution, nor for music mixing. The LFE point-one track is an example.

"LFE" stands for "Low Frequency Effects," and "Effects" means "sound effects." To allow the reproduction of powerful sub bass effects in analog movie soundtracks asteroids crashing into the Earth and dinosaur footfalls for example it was necessary to assign such signals their own channel to minimize intermodulation distortion and other unwanted artifacts, and maximize headroom.

The home theater revolution, however, has been founded on digital, and not analog, audio. Intermodulation of extreme bass with other channels does not happen. Not only that: all the channels have a complete low end you can put almost any amount of bass on any channel you like without problems.

The nearest you might get must be recording real cannons for Tchaikovsky's 1812 Overture, as Telarc did a year or two ago when they recorded their new version for SACD and DVD Audio release. But the new 1812 like several Telarc recordings and some from other companies uses the point-one track at least in part to carry height information. [Checkout Telarc's Michael Bishop's article on the height LFE channel in our May/June 2002 issue of Surround Sound Professional.] "With Bass Management," says the blurb in the disc booklet, "the LFE channel from the disc is redundant!”

The purpose of bass management is to ensure that whatever channel bass is on, it is fed to speakers that can handle it. There are many different speaker configurations that a consumer replay system might have, from five full range speakers and no sub to four tiny little boxes with a hefty powered subwoofer in the corner. Even a system with five full range speakers needs bass management to ensure that any T Rex footfalls that appear only in the LFE make it to the speakers that are actually present.

Bass management can only be implemented in the digital domain so that for bass redirection to occur in multi-channel music recordings it would have to be done in the DVD player and not the receiver/processor. The receiver/processor has bass management for the incoming digital signals recorded in Dolby 5.1 or dts it cannot be applied to the six channel analog input.

Nobody at home will know if there is nothing in the LFE: if they have a sub and put their ear to it, they will hear something (the bass from all the other channels: bass management in action) so you can't tell. If the sub-woofer is intrusive then simply switch off the woofer when listening to music discs.

The golden rule is to make sure that the speakers you choose for your system are five full range units and if for any reason you have been sold some of those nasty little satellite speakers that cannot reproduce bass hook then up with the sub-woofer as in a stereo setup. Then later add a real sub-woofer for the video discs in your life.

[Dre J]

Andrew, this explanation is a load of marketing misinformation.
Rotel's units are "NOT" allowing the signals to go to the speakers and Subwoofer unaltered.

The subwoofer choice for "Yes" or "Max" is broke. This is as defined in my series of bass management reports and solutions. The simple fact that they do not allow the user the ability to receive a clean unaltered signal for Analog 2-channel, LPCM, and the multi-channel inputs is a shame. They can double or triple the bass all they want, but give the audiophile the option to turn that crap off and receive a pure unaltered signal.


I'm very disappointed that Rotel would even attempt to pass such a marketing ploy across.

I've purchased my last piece of Rotel equipment.

For further review of my Bass management reports, see the following link.

URL Rotel RSP-1066 Bass management Report




My little corner of the world

"ILL-PLEX 007.1"

[RWright]

Andrew and Dre J,

Mainly because of you two I am receiving a 1066 and 1075 Friday. I can't wait. I know what I am buying because I read Dre J's attachment, a well written, very "to the point" article on 1066's base management. I know what I am getting and am OK with it.

I just read Rotel's response. Well, let's just say again that Dre J's article was well written, and very informative, and leave it at that!

Thanks you two,

Joe

[RogueAngel]

The golden rule is to make sure that the speakers you choose for your system are five full range units

That's not a really a statement that makes much sense at all. Maybe there should be a warning label on Rotel products:"Do not purchase this product unless you have FIVE, SIX or SEVEN FULL RANGE SPEAKERS, damage is likely if not used with full range speakers."

It would be one thing to send the signals unaltered to the five speakers, but to have a set-up that sends duplicate information to the sub output below whatever setting the filter is at, is just plain wrong.

I just don't get Rotel's position on this. Luckily I'm not using the multi input........ but I was considering doing that in the future.

I'll just have to figure into the purchase of a DVD-A or SACD player the price of a new receiver or pre/pro and amp from a different manufacturer.

Such a shame, and shame on Rotel. :cry:

[JKohn]

Forgive me, not enough time at the moment to read the two articles you linked to; but I did read Rotel's response, and frankly it makes me a little mad so I have to respond. Rotel's respons is spin, plainand simple. All their talk about the LFE channel is a diversion. The LFE channel has absolutely nothing to do with the bass management problems that the 1066 has. The problem with the 1066 is how it handles bass in the main channels.

There are two issues with the 1066, and the above response does not in any way address either one.

First, in the case of the multi-channel analog inputs, or the two-channel analog inputs in stereo bypass mode, the bass for the main channels is not only left intact for those channels, it is also sent to the subwoofer. Hence the term, bass doubling. Please tell me how anything in the Rotel BS above addresses this flaw in the 1066 bass management.

Second, the Rotel setup menu gives you the choices for the subwoofer setting of No, Yes, and Max. As documented by Rotel, the Yes setting crosses over speakers set to "small" and send their bass to the subwoofer. Max, on the other hand, is documented as sending the bass from both large and small speakers to the sub, even though large speakers are not crossed over. Basically, the Max setting is for people who, for whatever reason, actually want bass-doubling. The only problem is, Yes and Max work in exactly the same way, giving you doubled bass for large speakers. This is clearly a defect in the 1066, there is no way you can possibly argue otherwise.

I find it pretty ironic that they recommend you have all full-range speakers plus a subwoofer, because that is exactly the configuration in which the problems with the 1066 bass management will be most apparent. After all, if you have bookshelf speakers all around, the fact that the bass from those channels gets duplicated for the sub won't be too noticeable, since the bookshelves can't reproduce that information. (Actually there is one negative effect, you're putting much more strain on your amps, but I'm even willing to overlook that for now). On the other hand, if you have large speakers and a sub, which is what the "optimal" home theater is likely to have, you're going to be hearing the same bass information coming from both the sub and the mains. This can cause all kinds of problems with bass response, from bloated, boomy bass to phase issues that cancel out certain bass frequencies altogether.

To me what it really boils down to is choices and flexibility. If Rotel truly believes that doubled bass analog inputs is a good thing, they're entitled to that opinion. In fact some 1066 users may agree with them and prefer that configuration. The real problem is that we have no choice, because there's no way to disable this behavior if the user feels that it isn't optimal for his or her configuration. The fact that bass-doubling is forced on the user with no way to disable it is either an oversight or arrogance on Rotel's part, but it definitely isn't a good design.




Jeff Kohn

http://home.houston.rr.com/jeffkohn

[sdecker]

Come on Rotel!!!

Stop blowing smoke and fix the problem. You say there is no problem....

Then why does the 1055/1066's BM not work the way the manual describes?

Dont get me wrong I'm happy with my 1055 about 90% of the time, I only have about 5 SACDs. I ended up turning of the sub in the multi sub setup and use it as a analog bypass.


Earle

[Mark Paquette]

Wow! This line of marketing dribble really changes my opinion of Rotel. I've been struggling with deciding between a 1066 / 1075 combo or a Pioneer Elite 49txi receiver. I don't currently own any DVD-A titles, but my DVD player is capable of playing them and I did plan to buy some in the future. This response from Rotel really changes things for me. It's one thing for a company to have a problem with their equipment, own up to it and either fix it or say sorry we can't fix it. But it's another thing to deny the problem even exists in the first place, ie. Ford and Firestone.

[Andrew Pratt]

How come I knew this would get people talking :LOL: I'm still trying to bridge the gap between what the members of club rotel want to see and what Rotel thinks...I haven't given up yet

[Daryl Furkalo]

This is really interesting news. I will be looking for a new processor later this year to mate to my Rotel amps. I was seriously considering the 1098 or the 1066 from Rotel, but I haven't started doing much research yet. Bass management on multi-channel analog inputs is very important for me, as I have separate SACD and DVD-A players, with a growing collection of the software.

[Danbry39]

Andrew,

What response do you get when you talk to the higher ups at Rotel? Do they seem to be giving you a runaround or do they hint that they recognize the concern of owners regarding the double-bass issue? Have they indicated at all that they are working on or expect to have a solution? Surely they know that denying the problem isn't going to be satisfactory. That's like an ostrich sticking his head in a hole in the ground to protect itself. We'd all like to know whether they can fix the problem, whether they agree it's a problem or not.




Keith

[JKohn]

Andrew,

I understand that the bass-doubling on the analog inputs is probably something fundamental to the hardware and that can't be fixed with a firmware update. While I'm not thrilled about this, I can accept that that's just the way the 1066 works (though I still maintain that if the 1098 works the same way they will be making a huge mistake).

What I'm most interested in hearing is whether or not the've acknowledged the Sub=Yes/Max bug, and whether they're going to fix this in the firmware. There's really no way they can claim this behavior is by design, because it doesn't work as documented by Rotel, and what possible reason could there be for having the two settings behave identically.




Jeff Kohn

http://home.houston.rr.com/jeffkohn

[Andrew Pratt]

I just got of the phone with Rotel's VP and we had a long pleasant chat about bass management and rotels position. I think its safe to say that Rotel does care very much about what we have to say and is genuinely interested in providing us with a product that works as it should and conforms to standards set by the industry. Part of the problem is that the standards don't always seem to fit with trends in the industry. One example I'm thinking of here is the 5 full range speakers for DVD-A and SACD. Most of us don't have what we typically think of as being full range speakers in all five positions yet this is what the DVD-A and SACD authors assume. The question is what is Rotel supposed to do about it? They can build a product that conforms to those standards but people will (have) complained that there's no bass coming from their sub since they own small bookshelf speakers. To "fix" that Rotel added a bass redirect to the analog inputs where part of the low bass (~80hz) is sent to the sub and part to the mains...now this isn't double bass at this point since its not split at 100 percent signal strenght but split so that it sums back up to 100 percent. If you don't want that to occur simply set your sub to off. Rotel is looking into the Yes/Max issue and should be getting back to me with their findings soon.

I know there's a lot of you that are frustrated with the situation but please know that Rotel is listening to our concerns and will do what they can to make the products we purchased work as they should.

[JKohn]

now this isn't double bass at this point since its not split at 100 percent signal strenght but split so that it sums back up to 100 percent.

This is interesting if true, but I wonder if there's anyway to verify this claim. With all due respect to Rotel I can't help but be a bit skeptical about this because since the 1066's introduction the supposedly official replies from Rotel on various issues (many bass-management related) have been in many cases ambiguious or flat-out contradictory.

The real problem I have with the current 1066 situation is that the way it works is probably OK if all your speakers have similar capabilities: for smaller speakers, the sub redirection is probably a good thing, and if you have all large speakers you can just turn the sub off. The problem as I see it is when you have fairly capable towers for your main l/r speakers, but less capable center/surround speakers. In the latter situation you pretty much have to compromise, either getting some doubled bass from the mains or throwing away some of the bass from the other channels.

Andrew, please do let us know as soon as you hear something from Rotel on the sub Yes/Max issue. This should be very easy for them to reproduce, and it's clearly a bug/flaw.




Jeff Kohn

http://home.houston.rr.com/jeffkohn

[Kevin C Brown]

Still BS in my opinion. So now Rotel is *assuming* they know what speakers I have?

[Andrew Pratt]

The problem as I see it is when you have fairly capable towers for your main l/r speakers, but less capable center/surround speakers. In the latter situation you pretty much have to compromise, either getting some doubled bass from the mains or throwing away some of the bass from the other channels.

The problem isn't then that the Rotel doesn't do what it should but that you own speakers that don't fit the DVD-A and SACD standards. They didn't set those standards someone else did yet we expect Rotel to fix/patch it.
As for doubled bass assuming that what I was told about the splitting of the bass between the sub and mains is valid there isn't a double bass problem since it should still add back up to 100 percent.

So now Rotel is *assuming* they know what speakers I have?

No the people that wrote the specs for DVD-A and SACD did as well as the guys mixing the discs you're playing.

[JKohn]

The problem isn't then that the Rotel doesn't do what it should but that you own speakers that don't fit the DVD-A and SACD standards. They didn't set those standards someone else did yet we expect Rotel to fix/patch it.

Oh come on. How the discs are mastered is irrelevent. What matters is what the pre/pro does with the bass. Rotel is making an assumption that is not valid in many cases. Having towers that are larger and more capable than the other channels is a very common scenario. If Rotel truly believed that, why would they have more flexible bass management for digital audio sources?

You know what's really sad? In the near future I'll be able to play back DVD-A's on my HTPC, using a soundcard whose software has full bass-management capabilities. If Rotel woudl just do a true pass-through without the bass summing, I would be OK. Same thing no doubt goes for people with DVD-A/SACD players that have bass management capabilities.

As for doubled bass assuming that what I was told about the splitting of the bass between the sub and mains is valid there isn't a double bass problem since it should still add back up to 100 percent.

As I mentioned, I'm not quite ready to believe this is true. They've never said that before, despite there being much discussion of bass-management when the 1066 first shipped and the bass-doubling was discovered.

I'll say this though, a big part of the problem is that adding analog bass-management means extra cost, and the CE manufacturers don't want that. Once firewire connections become common-place this issue should largely disappear (well, assuming no bugs such as the Yes/Max bug). That's why I'm surprised the 1098 apparently doesn't support i.Link.




Jeff Kohn

http://home.houston.rr.com/jeffkohn

[Andrew Pratt]

If Rotel woudl just do a true pass-through without the bass summing, I would be OK. Same thing no doubt goes for people with DVD-A/SACD players that have bass management capabilities.

The problem here though is that Rotel can't win either way. I was told this is what they wanted to do to start with but the dealers said they had to include some sort of bass redirect.

'll say this though, a big part of the problem is that adding analog bass-management means extra cost, and the CE manufacturers don't want that. Once firewire connections become common-place this issue should largely disappear (well, assuming no bugs such as the Yes/Max bug). That's why I'm surprised the 1098 apparently doesn't support i.Link.

In addition to the extra cost (adds about $150 to the cost of each peice of gear) there are sonic disadvantages to BM in that it taints the sound. Apparently there was a review recently dicussing this in one of the british mags (not sure which Hi-Fi something I think) I think that's likely why DVD-A/SACD want us to use 5 full range speakers not BM to get the bass.

Interestingly enough we've been told with DD and DTS that all our speakers ought to be set to small no matter what they can do for bass but there's a strong sentiment starting to grow that for SACD and DVD-A maybe our perceptions of what a "small" and "large" speaker are. I mean when I think of large and small in reference to movies I think of speakers that have to reach down to 20 hz which we all know is damn near impossible for towers to do...but with music there's very little material that goes anywhere near that low. My speakers can all reach down to 40 -50 on their own so maybe for music calling them small isn't the best solution.

[Mark_C.]

Those who continue to complain about alleged bass problems with the 1066 forget that DVD-A and SACD were designed with full-range speakers. They keep trying to force the manufacturers to "patch'' the shortcomings in their own systems as to the DVD-A and SACD specs.

[Kevin C Brown]

Rotel *can* win. They make the "double bass" *feature* user selectable. Or, they get rid of it entirely. Plenty of DVD-A/SACD players these days that do BM themselves. Nobody complains about the *lack* of double bass on pre pros/receivers with straight passthrough. Or, they add an analog crossover to the 5.1 inputs.

And, I have towers for the front L & R *and* for the surrounds L and R. How does the 1066 handle my case? Very badly.

Andrew, you're a super duper good guy, but I can't believe you're trying to rationalize Rotel's position.

I would personally have *much* more respect for Rotel if they admitted that they shouldn't have done it this way.

Just curious, how will the 1098 do "BM" on the 5.1 analog inputs. I betcha it isn't this way...

[JKohn]

The problem here though is that Rotel can't win either way. I was told this is what they wanted to do to start with but the dealers said they had to include some sort of bass redirect.

This just reinforces my opinion of most dealers.

In addition to the extra cost (adds about $150 to the cost of each peice of gear) there are sonic disadvantages to BM in that it taints the sound.

If you have a crossover point and slope that integrates well with your speakers, the only real disadvantage is some minor phase issues. On the other hand, ditching a sub and going with full-range speakers all around has quite a few disadvantages (aside from cost and room decor):

1) EQ'ing the sub to get a smooth bass response is a pretty easy thing to do. Trying to get a smooth bass response when the bass is coming from speakers all over the room is going to be considerably more difficult, if it's even possible at all. I don't know about you, but my living room bears very little resemblance to an anechoic chamber.

2) Sending the bass to your towers/bookshelves (even if they can go down into the 30's or 40's), puts more strain on your amps. It also can muddy up the sound of your speakers, affecting not only bass but also midbass and midrange sound quality.

3) If you're worried about phase issues due to digital bass management, what makes you think you won't have phase issues with speakers at opposite ends of the room? Getting absolutely perfect phase response from a 6 or 7 channel speaker system is just not possible in the real world. But that's OK because most people don't even notice the slight phase issues introduce by bass management or EQ-ing

Apparently there was a review recently dicussing this in one of the british mags (not sure which Hi-Fi something I think) I think that's likely why DVD-A/SACD want us to use 5 full range speakers not BM to get the bass.

Those who continue to complain about alleged bass problems with the 1066 forget that DVD-A and SACD were designed with full-range speakers. They keep trying to force the manufacturers to "patch'' the shortcomings in their own systems as to the DVD-A and SACD specs.

These same high-falutin' audiophiles are the ones telling us that the Home Theater oriented speaker setup should be ditched in favor of a 6 channel system with the sub being replaced by a height channel. Sorry, that's not going to happen in most of our homes. You can look down your nose and say the problem is our inferior equpment, but the fact is even if my equipment isn't the perfect ideal for multi-channel audio that doesn't mean I shouldn't expect to get the best performance I can out of it. But the 1066 won't let me do that in the case of analog audio sources. I don't see why this is hard to understand.

So just in case Rotel still doesn't understand where we're coming from on this issue, let me try to repeat it one more time in the simplest terms possible. If Rotel thinks their current analog bass (mis)management is a good compromise for most systems, they're entitled to that opinion, and I'm sure some people (aka dealers) may even agree with them. The problem with this feature is that it can't be disabled. If it could, people would at least have the option of using the bass management in their DVD-A/SACD players, or they could hook up an Outlaw ICBM or some other similar product. By Rotel forcing this behavior on us, they are limiting our flexibility to get the best sound possible out of our systems, and that is not a good thing. And I can assure you my next pre/pro will not be from Rotel if they continue to force this "feature" on us in future products.

By the way Andrew, I'm not trying to come down on you, I realize you're just the messenger and I appreciate all the help you've been in acting as the go-between for us. My disappointment is with Rotel, not you. And I think you're a smart guy who's reasonable enough to understand where we're coming from here.




Jeff Kohn

http://home.houston.rr.com/jeffkohn

[Andrew Pratt]

Jeff Kohn please email me. I'd like to talk with you a little about the issue at hand.

[Corybuff]

This is my first ever post.. to any forum..I am probably like alot of people who lurk late at night reading other's opinions and who are happy never to partisipate but like to learn all they can about particular products before they make a purchase. I now feel compelled at this point to join in and offer my opinion, how ever humble. Last month I purchased Rocket Speakers from AV123 after reading about this product for weeks on the forums.. I have been extremely happy with this purchase..but more importantly I have been extremely amazed at how this particular company(Av123 Rocket) deals with their customers. A great business plan!! An excellent quality product, a great price, and unbelieveable customer service and support. I took a gamble since this product is only available on the internet and I was never able to audition these speakers.(Yeah, I know, a big gamble.) In all ways this "gamble" paid off way more than I expected. I have been very, very happy with this purchase...Now, next step, replace my 12 year old Pioneer Pro logic receiver. After much research I narrowed it down to either
1) the Rotel 1066 and 1095 amp or 2) the Outlaw 950 processor and the 755 amp. In my conversations with Outlaw I was extremely impressed with their customer service but they were having a problem at that time with a "hiss" that many of their customers were complaining about. You could read all about it on their website forums. They were acknowledging the problem, and were guaranteeing all their customers that they would stand by their products unilaterally! In fact there was correspondance on their website from customers who were not satisfied and did indeed return their product. But for me the Outlaw products are just butt ugly and I knew for me that in the long run I may not be happy no matter how good the product is. Now to Rotel...off to the dealer I went to look at this product. Instanty I was in love. Beautiful sound, all the features I wanted ...however the price was about $1,200 more than the comparable Outlaw products. I don't care, I can justify the price. I want this product now. In further conversations with the sales clerk he said no discounts on list price whatsoever..If I didn't buy this product there would be someone in later in the day who would...OK.. whatever.. when I asked about the base management issue I was told that he never heard of this issue and that "I shouldn't believe everything I read on the Web."Red Flag! I told him I had to do some more research and would "think about it." So for the last 6 weeks no purchase. Every night when I get home from work I open "Club Rotel" to find out the latest on base management. Andrew Pratt and other's information and passion for this product has helped me to want to be a believer for this company and be a member of "Club Rotel." and to eventially buy the RSP- 1066..but for weeks and weeks there was no further information on this base management problem..nothing..I kept reading the forums but the subject seemed to disappear...maybe it wasn't that big of a deal but maybe I should do more research, obviously the dealer I had delt with was going to be of no help. In the meantime Outlaw has resolved there hiss problem and has continued to stand behind there product through it all..no unhappy customers seem to be surfacing. Outlaw stepped up to the plate and delt with their problems.. Imagine how disappointed I and alot of other Rotel supporters are when the "base management subject" finally resurfacesin the last couple days and it just alot of "spin'. Nothing mentioned for weeks! and then the current response. I am not a technical audiophile and probably would have bought the product and may have never known about the problem but what a diservice Rotel does to themselves to handle it in this way. A great company, apparently a great quality product and then a mis step such as this that will probably haunt them for a very long time. Don't underestimate the power of the "Web". It is probably not too late for them to repair their public relations damage..but if they continue to spin and spin it will be like the preverbial "tar baby". I hope the powers that be are smarter than that. Rotel: you have alot of strong supporters. (Andrew Pratt, incl) Don't let them down..and let your dealer's in on the "base management secret" Educate them with the true facts so they can deal with the problem head on, factually. Let's keep our fingers crossed that Rotel does the right thing. I am still hoping. I am still in love with that 1066!!

[RogueAngel]

To "fix" that Rotel added a bass redirect to the analog inputs where part of the low bass (~80hz) is sent to the sub and part to the mains...now this isn't double bass at this point since its not split at 100 percent signal strenght but split so that it sums back up to 100 percent.

Okay, ya'll can call me a stupid woman, but I just don't understand something here.

One, they have a filter that can re-direct bass (from who knows which and how many channels) to the mains and to the sub output.

Two, you can avoid sending bass info to the sub by saying "no sub". Does this really remove the filter from the circuit? Or does it just not forward on that portion that would have gone to the sub.

Okay, here's where I get lost..... how come they can filter some portion (say 50%) out of the program material and send it to the sub and they can't filter 100% and send none to the mains. The way I think I'm hearing it is two choices only: half and half between mains and sub or all to "not the sub".

If you have the sub set to yes, does this mean that only the L/R and the sub share the bass ( which in my case would mean four sources of bass), or do we then have 7 sources of bass info to deal with.

The seems very disjointed to me....... why just part to the sub.

Those of us using the 1055 are really caught in a bind for multi-channel. The ICBM solution is not an option for us unless we are using it as a pre/pro. If only bass from the mains is shared with the sub, then something like the X-30 or a plate amps crossover can't be used, becuse not all the bass info goes the the mains.

Now if the L/R and the sub are the only ones getting the bass, then why can't the sub get it all if the sub is set to on?

Can someone clarify this for me............I'm not getting exactly what this filter is working with and if it's all 5 channels why it couldn't be made to send everything to the sub.

Help a girl out here, please?

[Andrew Pratt]

Guys this process of talking to Rotel and having them understand what we're saying isn't going to happen instantly...even if they did see what we want it could take some time before the questions we're asking get answered by the techs that have the answers...all I'm saying is before we all jump up and down saying rotels' ignoring us and trying to spin it their way lets see what they come back with on how it all is currently working and what could be done about it. Rotels not the largest company on the planet but they're spread out over many time zones so a question from me to the VP to the techs back to the VP and then on to me isn't going to happen over night One of the questions rogue asked is the very one I posed to rotel so if we can sit back toss in a CD or movie and enjoy the sweet sound we have now while we wait life will seem a little more enjoyable

[RogueAngel]

I agree Andrew, I know it'll take a bit for Rotel to digest this. I'm sure they're considering that all this is coming mostly from people that are very happy with our purchases of 1055's, 1065's and 1066's.

We are also, from what I've read here and on other forums a pretty savvy group when it comes to how all this integrates.A lot more than I would give credit to many of the dealers I have met over the years. As with everything else we've suggested or asked for, it's always been in an effort to help them make a fine product better and more enjoyable .

I guess most of us are a bit frustrated because we aren't able to communicate directly and get feedback that they're even understanding what we're saying. I'm really impressed that Rotel has issued so many software upgrades to this point. It does show they care what we think, for the most part...I'm still a bit miffed about the mute thing....and I for one appreciate the changes.

So I am enjoying it what I have...... just want to help make it better....... better is a good thing.

[Kevin C Brown]

This isn't something new that Rotel just found out about:

http://www.htguide.com/CFBoards/index.cfm?fuseaction=Threads.viewthread&CFB=1&Tid= 43237&Forum=25&DoOnePage=Yes&RequestTimeout=500

I even talked with Mike (of Rotel) on the phone about this very issue approx last Sept. And no, they didn't have a good answer back then either.

[Chris D]

Correct me if I'm wrong, people, since I haven't been heavily involved with the BM thread. But it seems to me the best solution for proper bass managment for a variety of speakers would be this:

1. An option to identify each speaker in the system as "large" or "small", basically identifying whether they have the capability to reproduce bass.

2. For ALL media sound that is sent to a speaker set to "large", the full audio range would be sent to the speaker, including all of the bass.

3. For ALL media sound that is sent to a speaker set to "small", ALL bass below a certain "crossover" frequency (allowance made for proper fade-out at crossover freq) is sent exclusively to the subwoofer, not the intended speaker.

4. Ideally, the set crossover frequency and amount/rate of fade in/out would be able to be set and adjusted for each speaker. (i.e. your center channel may have different capabilities than your surrounds and you may want the difference)

5. For digital sound with a dedicated LFE track (DD, DTS, etc) all sound is sent exclusively to the subwoofer.

Therefore the subwoofer does double duty, reproducing it's own dedicated LFE track when it exists, as well as low freq non-directional sound from any other channel that was set to "small".

For those who don't have a subwoofer, all other speakers would default automatically to "large", and the LFE track would be routed to the other system speakers. (probably mains)

I can't really see many downsides to this approach, but it seems most accurate and adaptable to me. Wouldn't this work with anyone regardless of their setup? Am I way off base?




CHRIS
Luke: "Hey, I'm not such a bad pilot myself, you know"

[JKohn]

Chris,

The way you've described it is pretty much how the bass management would work on the 1066 for digital sources, assuming Rotel fixes the Sub=Yes/Max bug, which I'm hoping they can do in a firmware release.

The bulk of this thread is discussing bm for the analog inputs, though. Things are a little different there. The reason is because the 1066's bass mgmt capabilities are digital, they're provided by the DSP. So they really can't be applied to analog inputs unless you want to take the step an extra A/D D/A conversion, which I don't think any of us would want. Rotel apparently decided that imperfect analog bass management was better than none, so they installed a low-pass filter to send bass to the sub. The problem is that the large/small speaker settings are ignored, and since there's no corresponding high-pass filter for the other speakers the bass ends up getting doubled.

Whether the analog bass management can be changed with a firmware update remains to be seen, but I would be surprised if it can, honestly. This is something we're probably going to have to live with (though I would love to be proven wrong here). But at the very least I want to make sure Rotel understands our concerns and doesn't repeat this mistake with the 1098.




Jeff Kohn

http://home.houston.rr.com/jeffkohn

[Andrew Pratt]

Jeff have you called Mike yet to discuss this matter? just curious.

[JKohn]

I tried calling him once on Friday but couldn't get a hold of him. Hopefuly we'll be able to chat before he leaves town next week...




Jeff Kohn

http://home.houston.rr.com/jeffkohn

[Danbry39]

Me thinks that Cory Buffs post has a very strong significance. First of all Cory, you stated what you had to say very nicely and I'd love to see you post more often. But, what I found interesting is that Cory probably represents a large amount of people out there, silent on the boards, but watching with credit cards ready to purchase. He, and a lot of others, might really want to buy Rotel products, but Rotel's response to an issue with their products, keeps them from going ahead and doing so. They'd sure get a lot more new customers and repeat business if they did. I have to say again though that I love my 1066 and think Rotel's products and customer relations are way above average. At least they're listening. But, I really do wish they'd just give us more feedback on this one problem




Keith

[karlie]

The problem with the phases arises mostly when you want to set different cut off frequencies for the different channels: so you should not, choose one for all speakers otherwise your sub will suffere from the phases differences.

Other than that I can only advise Rotel to read the documentation from Dolby that describes how to do Bass Management in digital or analog domain (that part is a mandatory item in Dolby's spec).
May be we should buy them an ICBM for them to understand.

Sure the cost of having analog cicuitry to do proper audio filtering is expensive. And by the way implementing high pass filters (removing the bass) is much more expensive than low pass filters (keeping only the bass) so that may be the reason why we ended up with double bass.

Ok now I will be looking at Marantz and Denon instead in April, unless they fix the 1098 before then (I also wish they come up with a 1068 without that stupid LCD screen).

[Bruce]

Part of the key to understanding bass management in the 1066 revolves around what Jeff said

The reason is because the 1066's bass mgmt capabilities are digital

This is true even when you select the 2-channel or multi-channel analog bypass.

You may ask how?
All analog input signals are Always automatically copied and sent through an ADC (analog-to-digital) conversion process.

This full frequency signal is then submitted to the bass management filters and the result (low-pass output called bass) is sent through a DAC (digital-to-analog) conversion process.

This low-pass analog signal (bass) is always sent to the sub-out when sub=Yes or sub=Max (unless SUB=NO is selected) . It doesn't matter what you have you main speakers set to (Large or Small), the bass is always being sent to the sub-out.

The 1066 bass management for analog sources is simply not implemented correctly, analog bypass should be analog bypass without any adulteration.




Bruce
____________________________________________

[John LaCava]

WOW, what madness!!! I'm just going to state my oppinion here for the record, it is lengthy and perhaps a bit mudane since I cover much material that has already been stated, but I want to be very clear how I see things, so that you will understand why my current attitude has become anti-rotel.

First and foremost, a fact is a fact, this Rotel unit RSP-1066 is indeed suffering from a very tragic malfunction. This is the Sub "YES/MAX" issue. There is no other problem from where I stand, but this is indeed a big one. As described in the manual, setting "yes" redirects bass headed for "small" speakers and send this to the sub, this would be in addition to any LFE intended for the sub in DD or DTS sources. The "MAX" setting is supposed to double bass in large speakers and redirect bass for small speakers.

If Yes worked there could be no problems as the crossover frequency (hi + low pass filters) can be set accordingly, or turned off to use the subs own low pass filter (avoids phase issues of two low pass filters mentioned elsewhere in this thread/froum) and 100Hz hi-pass applied to small speakers (I really wish this were selectable though, but since the sub yes/max doesn't even work right to begin with this is a moot point!). The above described situation sounds more or less ideal to me and is the reason I bought this damn processor!!!!! ARRRGGGHHH. It is a great blend of options for bass mgmt for Home theater enthusiasts and two channel (+ sub :LOL: ) and soon to be 6 channel audiophiles. But it doesn't work at all according to what I have read here.

With two large front speakers and two large rears speakers I can expect a bass doomsday when I add a sub to this system. Why would I add a sub with large speakers, clearly so that I may benefit from LFE in DD/DTS and anything recorded on the sub channel of a DVD-A/SACD recording. There seems to be a lot of time spent trying to prove this channel is not used in the primary posts to this thread, but the format is meant to support it (by design!) and therefore I can only imagine that it may be used.
To expect bass doubling on any source as long as my sub setting remains yes is not desirable functionality.

It is not outrageous for me to expect this device to operate as advertised! I purchased it because it was advertised as a 6 channel pre/pro with excellent bass mgmt!! It is absolutely spitting in my face to "spin" (as others have called it) the issue after I spent £1000 on the item. Its unforgivable that Rotel does not make their delears aware of the issue, mine had no clue about it when I appoached for a possible return.

End of the day is that this will be my very last rotel product ever if the issue is not resolved or I am not offered some concession to make up for the FALSE ADVERTISEMENT of the capabilities of this unit. All those other firmware updates etc. are not winning any favor with me when the unit is still shy of its advertised capabilities, those for which I purchased. I don't see how any intelligent person, who also values their hard earned cash, could see it any other way.

Rotel owes me a fix for (or something/anything!), but I haven't heard them suggest anything except that we should take what we were given and be happy.

I'm not sure if it was mentioned here, but when the sub is set to max (or yes since its broken) is the crossover setting in effect for the large speakers? That is to say if I set the corssover to 40Hz then I get the 40Hz low pass filter on all channles, but high pass only on small speakers right? Or is it stuck at 100Hz so you get 100Hz bass doubling (rather than say 40Hz) on large ones? I seem to remember reading this somewhere, maybe in DreJ's stuff, pardon me if I have made a misunderstanding on this bit.

Well do you guys think my stance is unreasonable?
I'm happy rotel has updated the firmwares, but that is pale in comparison to how happy I'd be if they fixed the sub yes/max issue. Over all I feel like I bought a lemon. A new BMW with a suspension problem to make an analogy. No matter how much the dealer made the brakes better I'd still be stuck with a sub-par car.

John

[John LaCava]

Hi I reviewed the info in DreJs report and it appears that the crossover works in LPCM and Stereo, but is fixed at ~100Hz for multi (wow that couldn't be much worse could it!). Which more or less answers my question at the bottom of my post.

Also I noted that Bass doubling doesn't affect DD or DTS.

My position remains the same.

[AlvaroD]

Part of the key to understanding bass management in the 1066 revolves around what Jeff said

The reason is because the 1066's bass mgmt capabilities are digital

This is true even when you select the 2-channel or multi-channel analog bypass.

You may ask how?
All analog input signals are Always automatically copied and sent through an ADC (analog-to-digital) conversion process.

This full frequency signal is then submitted to the bass management filters and the result (low-pass output called bass) is sent through a DAC (digital-to-analog) conversion process.

This low-pass analog signal (bass) is always sent to the sub-out when sub=Yes or sub=Max (unless SUB=NO is selected) . It doesn't matter what you have you main speakers set to (Large or Small), the bass is always being sent to the sub-out.

The 1066 bass management for analog sources is simply not implemented correctly, analog bypass should be analog bypass without any adulteration.

As I was saying in another post, the bass-management for the multi-input is either done in the analog domain or only for the main channels because there's only ONE stereo ADC in the 1066, at least according to the service manual part list.

[JKohn]

As I was saying in another post, the bass-management for the multi-input is either done in the analog domain or only for the main channels because there's only ONE stereo ADC in the 1066, at least according to the service manual part list.

According to Mike at Rotel, the bass doubling is only done for the mains; I haven't tested this yet to confirm though (Dre?). But I also got the impression that it was done in the analog domain. The reason I say this is because he indicated it was not something that could be easily changed with a simple firmware update, which would probably be the case if it was done digitally. It makes sense if you think about it, because the anlog passthrough also has to pass the LFE channel through which it could not do digitally because as you mentioned there are only two ADC's. To do the bass redirection digitally I think you would need three ADC's: left + right + LFE.




Jeff Kohn

http://home.houston.rr.com/jeffkohn

[AlvaroD]

According to Mike at Rotel, the bass doubling is only done for the mains; I haven't tested this yet to confirm though (Dre?). But I also got the impression that it was done in the analog domain. The reason I say this is because he indicated it was not something that could be easily changed with a simple firmware update, which would probably be the case if it was done digitally. It makes sense if you think about it, because the anlog passthrough also has to pass the LFE channel through which it could not do digitally because as you mentioned there are only two ADC's. To do the bass redirection digitally I think you would need three ADC's: left + right + LFE.

wow, that's a first class information : we now know for sure that there's bass-doubling for main channels only, not as bad as we first thought. Thanks JKohn

About the ADC issue, I'm not sure digital bass management would need 3 ADC channels. The critical part in bass-management is the high-pass/low-pass filtering. It's much harder to do it right in the analog domain because of phase rotation.
The suming of signals is, on the opposite, easily done in the analog domain without any special form of distorsion. A basic operational amplifier would do.

Thus I think the digitalized bass portion of the main channels are simply added, in the analog domain, to the multi-channel sub input.

It would be nice to have a confirmation from Rotel though.

[Bruce]

Jeff K,

It is a fact, there is NO analog bass management in the 1066. All bass management for digital sources (DD, DTS, PCM) is handled in the digital domain. For analog bypass sources (2-channel and L&R mains for 5.1 bypass) bass management is inappropriately applied from a digital domain bass management algorithm which only requires a single ADC/DAC for the stereo L&R mains.

I believe the problem is essentially with the cirrus DSP chip and cirrus provided firmware, which is why the Outlaw 950 has a similiar problem, except the Outlaw does provide an analog bass filter (80Hz) for it's 5.1 analog bypass which is 180 degrees out of phase with it's own digital bass management (another stupid and incorrect implementation). This means you must manually flip the sub's phase switch (if it has one) when changing between analog and digital sources.




Bruce
____________________________________________

[AlvaroD]

Anyone tested the setting "OFF" for multi-channel input sub level in the new 1.49 firmware ?

Aint that just doing what we want : avoiding bass-redirection from mains to sub ?

[Bruce]

Anyone tested the setting "OFF" for multi-channel input sub level in the new 1.49 firmware ?

Just don't forget to turn it back to "YES" when you go to watch a DVD movie.

You must remember to switch back and forth from sub= "OFF" to "YES" each time you change between analog and digital sources.




Bruce
____________________________________________

[JKohn]

It is a fact, there is NO analog bass management in the 1066. All bass management for digital sources (DD, DTS, PCM) is handled in the digital domain. For analog bypass sources (2-channel and L&R mains for 5.1 bypass) bass management is inappropriately applied from a digital domain bass management algorithm which only requires a single ADC/DAC for the stereo L&R mains.

Hmm, I think if that were the case, they should be able to fix this with a firmware update, and I got the distinct impression from him that this was not something that could be addressed with a firmware change. I'll try to get further confirmation from Mike, but he's traveling this week so I'm not sure how long it will take.




Jeff Kohn

http://home.houston.rr.com/jeffkohn

[JKohn]

Anyone tested the setting "OFF" for multi-channel input sub level in the new 1.49 firmware ?

I haven't tested the latest firmware (still haven't gotten around to ordering a cable yet), but if this did work that would be a possible workaround. The only problem is that you'd lose anything in the LFE track (though I'm not sure if any multi-channel audio discs are being mixed with an LFE track).




Jeff Kohn

http://home.houston.rr.com/jeffkohn

[AlvaroD]

Just don't forget to turn it back to "YES" when you go to watch a DVD movie.

You must remember to switch back and forth from sub= "OFF" to "YES" each time you change between analog and digital sources.

I'm not talking about the "SPEAKER SETUP" menu where you can set the Sub to OFF/YES/MAX.

In the new 1.49 firmware, in the "SUB SETUP" menu, you can set the sub level for the multi-input to "OFF" instead of "MIN" for the previous firmwares.

[Bruce]

Alvaro,

In the new 1.49 firmware, in the "SUB SETUP" menu, you can set the sub level for the multi-input to "OFF" instead of "MIN" for the previous firmwares.

OK, so this means any 5.1 multichannel input (SACD or DVD-A) that actually has .1 or LFE content material will not be able to ouput that source content through the .1 or sub output channel, correct?

Sounds to me like a poor band-aid for the original problem that still exists, because this fix still doesn't correct the problem for 2-channel sources.




Bruce
____________________________________________