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Ukko Kari

Replacement AVR / processor

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Kvalsvoll    75

@SME, the typical 2-ch system actually lack basic and necessary functionality, such as delay on main speakers. This is the case for most 2-ch preamplifiers, including those with dedicated subwoofer outputs, even the digital ones. The most sophisticated may have some sort of low pass filter on the sub output, usually fixed slope and cut off frequency. 

And if the system has a AV-processor/AVR, they usually bypass all processing for 2-ch listening, in "direct" or "pure" mode. This efficiently disables all calibration settings for bass system integration - no delay, no filter on the mains. Alternatively, a dedicated 2-ch preamp is installed - all necessary functionality is lost.

So, it is no wonder the typical 2-ch system sounds better with subwoofers disabled. Even if they know how to set this up properly, it is not possible because the playback chain lacks necessary functionality.

Of relevance for this thread: Note that the amplifier test was done using a quite ordinary AVR as processor/DAC for playback, and no one has been able to detect any audible difference from the original to the sample that was passed through the playback-recorder loop 4x times. A reasonably good AVR, used correctly, does not have any "sound" at all, it is completely transparent.

All this is caused by bad advice given from manufacturers and dealers who want to sell more equipment and does not understand how to set up a sound system properly.

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SME    211

@Kvalsvoll, I was talking about 2 channel systems with full-range speakers without subwoofers.  They don't generally need delay because the low frequency drivers are co-located with the rest of the drivers.  This includes speakers using either passive crossovers to the LF section or active crossovers (with built-in amplification).  Some speaker / amp combos can extend as low as most subs go.  Either way, the integration is relatively trivial.

It could be said that using subwoofers, in separate room locations, solves one problem but creates another.  It (partly) solves the problem of poor in-room response in the sub frequencies at the locations that are otherwise ideal for the speaker.  It creates the new problem of integrating the speaker and sub response, which typically affects a region of frequencies that is crucial for reproduction of bass in music, around 60-120 Hz.  I'd argue that, for the vast majority of music, accurate reproduction of those frequencies is far more important than the extra octave or two of extension that people using subs chase after.  Nevertheless, I'd bet that the vast majority of systems using subs have serious frequency response problems in that range because this integration is not at all trivial.

I'm not saying that using separate subs is inferior to using standalone speakers.  A system that uses separate subs will absolutely out-perform a system using standalone speakers, *if* they they are configured optimally.  Rather, achieving the optimal configuration for a system with subs is not at all trivial.  It's hard enough to do with a single sub, and enormously more complicated with multiples.  Most consumers don't have the knowledge or equipment to achieve even half-decent results, and even the more advanced consumers struggle to get "good" results.  Count me among them.  I have more DSP capability than just about anyone on these forums along with subwoofers-only response that looks almost "picture perfect" , yet I'm still trying to find the best strategy for integrating my subs + MBMs with my mains.   :)

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Kvalsvoll    75

@SME  , this discourse kind of crossed the OT border somewhere, and should probably be moved to another thread..

I was going to say you are wrong, but I actually have to say I mostly agree. When I got back into audio some years ago, I found that people could not set up the system properly to get a good integration, and this severely compromises sound quality, because the timing in the most important frequency range goes bad. 

But it is not extremely difficult to get it a reasonably good result, at least so it sounds better than main speakers alone. But it requires much more than the casual buyer can do, because you need to measure. When you have the measurement capability, it is possible to achieve predictable results using a manageable set of rules.

Especially for 2-ch, the systems often end up with a very low crossover, because that sounds better. And does sound better, if you are not able to set the delay on the mains properly.

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