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Internal Passive Crossover Bypass


Moose1963

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13 hours ago, Moose1963 said:

Does anyone know how to get the recommended external active crossover frequency settings for Klipsch 6000F?

The Klipsch cut sheet says 1800 Hz, which is pretty typical for two-way tower-type home theater front loudspeakers, but that information won't be enough to do the job without some acoustic measurements.

 

It's generally found that loudspeaker manufacturers do not yet provide active (DSP) crossover settings to replace their internal passive crossovers, thus bi-amping/tri-amping them as required.  This would, of course, be an easy thing to provide in today's web-driven marketplace, but current practice doesn't include these DSP settings files (except for loudspeakers requiring DSP crossovers, such as professional cinema models).  This is the reason why you'll need to take the acoustic measurements yourself.  I've recommended a UMIK-1 and Room EQ Wizard to do this for your room/loudspeaker position within the room.

 

Chris

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The reason why it would be an easy thing to provide--is that loudspeaker manufacturers nowadays (typically) use DSP crossovers to find the initial passive crossover configurations and do tradeoffs to simplify the resulting passive networks.  It takes about 1/10th or 1/100th the amount of time to use DSP crossovers than to try the "cut and try" approach that was used before DSP crossovers were generally available and affordable. 

 

[The reason why consumers still buy passive crossover loudspeakers is largely due to ignorance of DSP crossover capabilities, since the required tools to use it is basically free once the low cost calibrated microphone and DSP crossover is acquired.  Only one DSP crossover is required for a pair of loudspeakers.]

 

Reputable loudspeaker manufacturers that are technically proficient that produce loudspeakers for home hi-fi, home theater, and even commercial cinema and PA duty--all will typically use DSP crossovers to dial in everything. Then the conversion to a simplified passive network can occur (in other words: the loudspeaker manufacturers could provide better passive crossover to further flatten SPL and phase response, but they won't), typically using something like LspCAD to simulate the results and significantly aid the design process using actual measured driver responses while they are mounted in the loudspeaker enclosure as inputs to the simulation, in order to account for the electrical impedance and actual driver acoustic responses:

 

nangilaja-xo.png

An LspCAD screenshot

 

So the DSP data already exists (and/or the raw response of each driver in the box)--all they have to do is publish the data they already have.  Today, loudspeakers manufacturers don't/won't provide this information to you, citing "proprietary data issues"--which is actually BS, since it's so straightforward for anyone to measure once they have the hardware in question (even audiophile reviewers could do it 😉).  Once consumers generally figure out the advantage of using DSP crossovers, I think demand for these DSP settings by consumers will increase rapidly as DSP crossovers continue to penetrate home hi-fi, as they have been accepted for decades within PA and cinema marketplaces.  The advantages of DSP crossovers use in terms of increased sound quality over passive crossovers far outweigh their disadvantages in terms of perceived increased complexity.  The economics of using DSP crossovers now makes them almost "commodity products" (price is determined almost exclusively by competition) in consumer electronics.

 

Chris

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18 hours ago, babadono said:

word to the wise... the Xilica units have a noise gate built into their DSP. They call it the Internal System Optimizer. You can only set threshold level or Bypass, not the attack or release times. And only from the front panel, not the XConsole GUI. It should be set to bypass for a real comparison of noise floor with different manufacturers units. Assuming the different manufacturers unit has no noise gate. Perhaps the Drive Rack has optional noise gate settings?

 

I don't see a listing for Noise Gate specifically, but the Drive Rack PA2 owners manual describes the procedure for setting Gain Structure and Limiters. Also available on many pro crossovers are menu selectable pre-sets for different pro amplifiers.

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On 2/17/2021 at 3:15 PM, Moose1963 said:

Super, thanks.  I think I get it.  You hit the switch on the triggered outlet strip to fire up the Rotel and then just use the CD player remote to control your source. Right?  

 

That will work, but I would prefer to turn the entire system on and off using the power button of the Rotel pre-amp, using its 12 VDC outs to trigger the other components.

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On 2/22/2021 at 6:23 PM, babadono said:

word to the wise... the Xilica units have a noise gate built into their DSP. They call it the Internal System Optimizer. You can only set threshold level or Bypass, not the attack or release times. And only from the front panel, not the XConsole GUI. It should be set to bypass for a real comparison of noise floor with different manufacturers units. Assuming the different manufacturers unit has no noise gate. Perhaps the Drive Rack has optional noise gate settings?

I turned off this feature on my Xilica XP-8080 a few years ago when I found out about it and turned it off from the front panel controller.  Apparently the default from Xilica is that it is "on" when shipped.  I believe it was you (babalugats) that found this feature and announced it on the forum.

 

The first time I used the Xilica for listening to program material (November 2016) was when I put this thread together:

 

The first show that I watched was a Netflix or Prime video in stereo format of a wildlife documentary film from India.  The audio on the film was muted most of the time (...and I mean "muted"...), and generally only when the narrator spoke at intermittent points to describe what was occurring (i.e., the weaved storyline of the documentary), an issue was found.  The audio would initially mute the narrator's voice, then the volume would ramp up over perhaps a second or so, then would be fine until the narrator paused for a few seconds, then the whole cycle would repeat itself again.  This was very disconcerting, but to date, that's been the only instance where the muting feature was creating issues. 

 

When I found that the only real noise in my Jubilees came from the XLR-->RCA balanced to unbalanced cables to the First Watt F3 amplifier (everything else in my setup uses digital buses which are immune to noise, or balanced XLR/Euro connectors for analog connections which block common mode noise), I found that turning off the ISO option on the Xilica front panel made no real difference in noise levels. 

 

That's when I realized the inherent value of the Xilica XP series crossovers--they are extremely quiet all by themselves, and they provide a way to control noise derived from upstream electronics.  That option (ISO) is there to mute if you have noisy unbalanced connections, but can easily and swiftly be turned off.  I've never turned it back on again, and have found the Xilica noise floor to be below audibility without it on (even when placing my ear inside the K-402s).  In general, the miniDSP 2x4 HD is quiet, but not quite as quiet as the Xilica crossover, in my experience.

 

Chris

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@Chris A  for clarification, are you saying on your system there was/is NO real (or otherwise) difference in hiss level coming out of your K402/TAD horns with the ISO bypass off/on?

 I tested it again last night and mine is definitely noisier(more hiss) with it bypassed.

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Hello,

I'm trying to bi amp my Klipsch 6000F speakers and am having a great deal of trouble.  Right now I'm running twin Marantz MM7025 amplifiers and the speakers are not responding.  Are two of these amps too much?  I notice that, in a Klipsch article by Dave Gans, it is recommended that a 150 watt amp be used for low range and a 50 watt amp be used for the high range.  I'm thinking about pairing a Dayton Audio HTA100BT 50 watt 2-channel tube amp with only one of the Marantz MM7025s.  Will this be a suitable amp combo for bi amping the 6000F?  Thank you. 

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