Has anybody figured out a way to avoid the "double bass" on the 5.1 input? According to a few reviewed I've read, even with the analog bass management switched off on the 5.1 input, the low frequency information for all the channels is summed and redirected to the LFE channel. This makes absolutely no sense to me. After all, some people are bound to have full-range speakers in their set-up. And doesn't this make it impossible to use the ICBM correctly with the 950?

Has anybody figured out a way around this problem? I contacted the Outlaws and was told that they have no plans to fix this in future production runs.

David,

This is a simple matter:

1. Switch the analog BM to 'on'...no double bass. (filters all sats @ 80 Hz and redirects sat's bass @ 80 Hz and below to the sub along with the full LFE signal...best choice)

2. Switch the analog BM 'off' and dial your subwoofer's LP filter to the F3 point of your mains...no double bass. (assumes all sats are 'large', but least desirable choice for various reasons)

3. With either of the above choices, the ICBM is not needed.

The Rotel 1066 has the same problem. But you cannot get around it unless you cut some resistors on a board inside the unit. Mess it up? You're out of luck because Rotel doesn't cover a user mod like under the warranty.

Likewise, Rotel has no plans to fix this in future production.

Would someone be so kind to explain what is meant by double bass.

At the moment I am using an ICBM between my Pioneer811 and Outlaw 755 in order to control some bass management problems I was having. Soon I will be buying a new pre/pro to replace the Pioneer. This topic has me concerned about my next purchase so I have a few questions.

If I were to switch to a Outlaw 950 would that mean my ICBM would be rendered useless when it came to the analog bass management?

My concern is as it was for David Olstein is using the ICBM with the 950 or any pre/pro having the double bass problem. Who knows I might be having the same problem with the Pioneer 811 and not know it.

Thanks for any input, LTK

[This message has been edited by Luvthekeys (edited August 15, 2003).]

"Double bass" refers to the scenario where you have bass management transferring information to the subwoofer output from other channels while leaving that information intact on those channels. As Kevin pointed out, both the Outlaw 950 and Rotel 1066 include a low-pass filter on the 5.1 analog input that passes material below 80Hz from the five full-range channels to the sub. The 1066 leaves those full-range signals unchanged, however, so that the "bass" information is output twice. The 950 has a switch to enable or disable a high-pass filter for the five full-range channels (the analog bass management that David refers to). If you are using the ICBM, you should not be encountering double bass (I don't know of any scenario where you could produce this with the ICBM).

With the 950, you would probably not need the ICBM between pre-amp and amp -- not useless, but basically redundant. The digital bass management on the 950 provides much the same functionality as the ICBM (separate crossovers for center, mains, and surrounds, with similar or identical crossover point options to choose from).

------------------
gonk -- Saloon Links | Pre/Pro Comparison Chart | 950 Review

The double bass issue will only show up when using the 5.1 inputs, correct?

-Joe

------------------
Remember the Intellivision?
http://www.gotmaille.com/nostalgia/

The double bass will only appear when using the 5.1 inputs with the analog bass management turned off or when using stereo bypass mode with the mains set to small (separate scenario).

------------------
gonk -- Saloon Links | Pre/Pro Comparison Chart | 950 Review

Here's a link to a general summary of the bass management on the 950 -- might help get anybody up to speed who hasn't been around for some earlier bass management discussions.

------------------
gonk -- Saloon Links | Pre/Pro Comparison Chart | 950 Review

[This message has been edited by gonk (edited August 15, 2003).]

Even thought the 950 has reasonably good bass management, I am using the ICBM between a 950 and the amp in order to run stereo subs. Stereo subs are discussed in other threads. In my situation stereo subs bring wonderful results.

I experience “double bass” using the 5.1 inputs if:

1) The analogue bass management switch is ‘off’ so that low frequencies remain in each individual channel until they arrive at the ICBM;
2) The .1 of the 5.1 is passed through the 950 and the SUB OUT of the 950 is used to feed the LFE IN on the ICBM.

In this case the low frequencies from each individual channel are combined with the .1 signal of the 5.1 for the SUB OUT of the 950. These are “seen” by the ICBM on it’s LFE input. But the same low frequencies are still in each individual full-range channel going to the ICBM. Because of this, the ICBM will have the low frequency information from each channel plus a mono mix of all the low frequency information from all channels at the LFE input. Thus “double bass.”

The solutions proposed by Bossobass do apply in some cases. A “messy” solution that has a “clean” signal result is to provide a A-B switch for the LFE input on the ICBM. In one position the switch selects the SUB OUT of the 950, in the other position it selects the .1 channel of the 5.1. This .1 channel is not connected to the 950. This requires additional cabling and an extra step in order to switch between 5.1 multi-input listening and any other mode … hence it’s “messy,” unless you want to modify your pre/pro and void the warranty.

I think this is one of those issues that are just not important enough to the designers, manufacturers and sellers of moderately priced pre/pro equipment to either think about in advance or care enough about at some point to actually make or offer changes.

gonk said:

"If you are using the ICBM, you should not be encountering double bass (I don't know of any scenario where you could produce this with the ICBM)."

If you wanted double bass with an ICBM, wouldn't the redirect switch allow you to do so?

Brian

<>

I was also planning on running stereo subs and was planning on taking care of all bass management via an ICBM (which I would put between the 950 and the 7100). In the set-up I'm looking at, the front left and right speakers would be full range, so I really don't want to have the low frequently information for the front speakers summed and directed to the LFE channel. Nor do I want the low frequeny information in the surround channels summed, since the plan was to have the ICBM direct the low frequency info on the left surrounds to the left subwoofer and the low frequency info on the right surrounds to the right subwoofer. Obviously, this is only a problem if you're using a DVD-Audio or Multichannel SACD player via the 5.1 input, but that's exactly what I was planning to do.

I suppose that one solution would be to bypass the 950 entirely and connect the DVD-Audio/Multichannel SACD player directly to a 5.1 switcher, and then connect the outputs of the 950 to the switcher as well, and then connect the switcher to the ICBM. But then we're dealing with (1) an awful lot of cables and (2) two devices inserted between the 950 and the amp, resulting in god knows how much degradation of the audio signal. Maybe someday we'll get an ICBM2, with two sets of 5.1 inputs.

Personally, I still don't understand why the Outlaws bothered to incorporate flawed analog bass management into the 950. It would have made far more sense not to have messed with the 5.1 input, and then those people who needed bass management for their DVD-A/SACD player could simply buy the ICBM.

Actually bestbang4thebuck's solution is a hell of a lot simpler than using a 5.1 switcher, since it's really only the sub-out on the 950 that presents a problem. That's probably what I'll end up doing.

<>

I can certainly understand why they'd be reluctant to admit that there's a design flaw in the 950, much less correct it. But it still amazes me that they even went this route in the first place. First of all, it's not as if people were screaming for analog bass management on the 950. Indeed, the Outlaws had already produced a separate device for that. And second, virtually all of the second generation DVD-A and SACD players incorporte some kind of bass management. So the problem the analog bass management in the 950 was designed to deal with is becoming less common, and now it's the 950 itself that's creating a problem by adding bass management where none is needed.


[This message has been edited by David Olstein (edited August 15, 2003).]

[This message has been edited by David Olstein (edited August 15, 2003).]

Hmmm... Sure enough, if you use the left/right recombine switch and set the main channels' crossover to something other than bypass (if you set it to 80Hz, for example), you can achieve double bass. Interesting...

I forgot to mention another bit of the "mess:" not only is there more cabling and an extra switch to make, but in this case, just 5 of the 5.1 channels have volume control via the 950, while the only adjustment for the .1 channel is on the ICBM. The LFE adjust on the ICBM is not really meant to be operated as a volume control. This means finding a couple volume settings on the 950 and the ICBM that match up well with each other in the 5.1 bypass mode, but it hardly gives one a maintainable balance with a volume control that can be altered from the listening position(s) with the remote.

I'm for sending $50 to Outlaw and saying, "Please supply a mod that allows me to defeat the 5.0 low frequency summing to the SUB OUT while maintaining my warranty."



[This message has been edited by bestbang4thebuck (edited August 15, 2003).]

Sorry, all. I didn't realize in the first post that the question centered around the use of the ICBM.

Also, I have a seperate processor that I built for an LFE discrete sub system, so the LFE signal never enters my 950 at all.

It's good to note here that the LFE channel is basically a double bass channel. That is, it's almost exclusively used to double, or boost the bass tracks of the other 5 channels.

The double bass refered to in this thread is when the 950's analog BM switch is set to 'off'. Then, the 5 sats receive full range signal while a copy of those 5 signals is sent to the SW output, filtered @ 80 Hz. and summed with the LFE signal.

My answer to this situation is a simple one. I connect the player's SW output to a one channel pre/pro that is specifically designed for LFE, which then outputs to it's own LFE sub.

This will allow you to set the 950's BM any way you like and use the ICBM very succesfully, if you like. You may also use 2 subs for stereo redirected bass (in addition to the LFE sub).

My LFE pre/pro actually has a crossover (as opposed to a LF filter) which allows an LFE satellite to render the LFE channel in Hi-Rez MC audio a full range channel. Or, you can set the crossover to, say, 60 Hz and use an upper bass sub to enjoy the full 120 Hz LFE range with punch.

Outlaw has maintained all along that the 'double bass' issue is not a serious one for most systems. That is, more or less, a correct statement (see my post above). Using the ICBM is a different story as this thread proves.

All I can really say is, what a difference a year makes! It's great to see so many posts from people who understand the LF of MC audio vs the utter state of confusion that existed this time last year.

As always, I point to Gonk as the go-to guy in this forum to at least get the ball rolling if not to nail the solution in, like 12 seconds after you post a Q.

I tried to bring up the phase cancellation problems of using stereo subs in another thread
http://ubb.outlawaudio.com/ubb/Forum6/HTML/000245-3.html

but no one responded.

I'm glad some of you are thinking about it (this obviously is different than the usual double bass issues here, but still).

My question is: Can you hear Double Bass and if so, How bad are the effects?

------------------
MeanGene's Home

MG- You can actually test this for yourself, but obviously, you need a 950 and any player hooked up to the analog inputs.

I remember a guy a while ago who got rid of the 1066 because of how much bass he got. Obviously user dependent on the room, and the kind of speakers you have.

Digital bass management is not applied in 6ch bypass. This is the main reason I am going to try the ICBM. However, I am disappointed there looks to be no clean way around the 'double bass'.

Does anyone know what would need to be modified on the board to eliminate this problem? I am very confortable with removing a few thru-hole or SMT components.

Is it possible with the 950 to set the crossover at different frequencies for front, rears and center? My Maggie MMGs (front) roll off about 50Hz, the center I plan to get at 80Hz and MGMC1s I plan to get for rear at 80Hz.

Pardon if this is a dumb, but I am new to bass management and it gets very confusing.

The 950's analog bass management (which applies only to the six-channel analog input, and is the bass management that David asked about at the start of this thread) has a fixed 80Hz crossover. The 950's digital bass management (which applies to all other operating modes) includes a "triple crossover" -- three separate crossovers for center, mains, and surrounds. It would allow you to set crossover points of (for example) 60Hz for your mains, 80Hz for your center, and 100Hz for your surrounds.

------------------
gonk -- Saloon Links | Pre/Pro Comparison Chart | 950 Review