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).

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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

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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).

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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.

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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