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Amplifier function - cut low frequencies from the stereo speaker outputs only

Blew

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I am looking to upgrade my current Marantz M-CR611 integrated CD/amp with something else. There is a function on this unit that allows you to set a low frequency cutoff for the stereo speakers. This is useful to direct those frequencies to the subwoofer instead, which has a separate output that's not affected by the setting. You can then set the high cutoff on the subwoofer to suit.

See the manual page below:

I would assume that this would also improve overall sound quality as the stereo speaker woofers would vibrate less due to producing less low frequency content and thus produce less distortion, but I haven't done much testing specific to this myself. I don't see this function available on other stereo amps, even Marantz ones. Where most amps have a dedicated subwoofer out they appear to have a high pass filter that only directs low frequencies out the subwoofer output, but don't cut those low frequencies from the stereo speaker output. While the Yamaha R-N803 YPAO function seems to do something similar automatically, I can't find a way that you can set this manually.

I know you could do this by routing the stereo speaker cable through a subwoofer that supports it, but that introduces speaker cable placement issues. Am I wrong to assume that this function helps through less distortion? Why wouldn't other stereo amps have something similar to this function? Is there something that I'm missing?
 

KMO

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Am I wrong to assume that this function helps through less distortion?
You're totally right. And there are are other benefits like being able to optimise bass and non-bass placement separately, and reducing the load on the amplifier itself.

Why wouldn't other stereo amps have something similar to this function? Is there something that I'm missing?

Because most people buying them don't have subwoofers. So there's not enough of a sales impact to make companies who don't provide the function copy those who do.

Also, from a marketing view, they tend to focus on "audiophiles" who treasure non-interference with the signal over actual useful audio processing. "We've got circuitry that could mess with your signal" isn't a selling point. Similarly for EQ functions. Reviewers won't generally give them credit for having the functions (although this may be changing).

Also cost, of course.

In other market spaces, like A/V receivers or proper professional stuff, the bass management functionality is universal, and anything lacking the ability would be laughed out of review.

I know you could do this by routing the stereo speaker cable through a subwoofer that supports it, but that introduces speaker cable placement issues.
I'm not aware of any subwoofer that will do this at speaker level. That would be semi-convenient - only cabling - if it was technically feasible, which I don't think it is.

And I was surprised how rare the function at line level is now - manufacturers like SVS that used to provide it no longer do (in most subs). Line-level sub processing requires separate pre and power amps, which rules out a lot of applications. And introduces a new place to be sceptical about signal processing loss - it would be nice to see someone like Amir technically review the crossover function on something like the KEF KC62 that has it.
 
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Blew

Blew

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You're totally right. And there are are other benefits like being able to optimise bass and non-bass placement separately, and reducing the load on the amplifier itself.
Glad to know I'm on the right track! Yes I want to add another subwoofer to place the two in the front corners of the room to supplement a pair of standmount speakers placed away from the walls. I want to try to isolate the vibrations of the standmounts rather than couple them to the floor, which is why I'd rather not pump bass through them when the subs are already doing that job. From what I can gather, isolating is the better option for a room that has carpet on top of suspended wooden flooring.
Also, from a marketing view, they tend to focus on "audiophiles" who treasure non-interference with the signal over actual useful audio processing. "We've got circuitry that could mess with your signal" isn't a selling point. Similarly for EQ functions. Reviewers won't generally give them credit for having the functions (although this may be changing).
The Pure Direct modes that I've seen in Yamaha and Marantz amplifiers seem to do a good job of solving the problem of extra circuitry generating noise. Yes you sacrifice EQ but at least you have the choice.

Also cost, of course.

In other market spaces, like A/V receivers or proper professional stuff, the bass management functionality is universal, and anything lacking the ability would be laughed out of review.
So then is an A/V receiver the best option for scenarios where two standmount stereo speakers are coupled with a pair of active subwoofers? Looking at the Marantz NR1510 and NR1711 A/V receivers, both appear to have the crossover feature I'm interested in, plus Pure Direct to bypass the unnecessary functions:
I'm not aware of any subwoofer that will do this at speaker level. That would be semi-convenient - only cabling - if it was technically feasible, which I don't think it is.
Perhaps I misread how it works then.

And I was surprised how rare the function at line level is now - manufacturers like SVS that used to provide it no longer do (in most subs). Line-level sub processing requires separate pre and power amps, which rules out a lot of applications. And introduces a new place to be sceptical about signal processing loss - it would be nice to see someone like Amir technically review the crossover function on something like the KEF KC62 that has it.
Is there any advantage in doing this at line level on the subwoofer over doing it at the amplifier as above?
 

sigbergaudio

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Here's a list of some amps and preamps with proper support for subwoofers:
 

KMO

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Is there any advantage in doing this at line level on the subwoofer over doing it at the amplifier as above?
Not inherently, no. The function's provided for people who don't have an amplifier/receiver/whatever capable of doing it.
The Pure Direct modes that I've seen in Yamaha and Marantz amplifiers seem to do a good job of solving the problem of extra circuitry generating noise. Yes you sacrifice EQ but at least you have the choice.
Don't know about Yamaha, but historically in Denon+Marantz, "Direct" turned off all processing on the signal path, except gain controls. So it ruled out bass management. (And "Pure Direct" just shut off extra circuitry like video processing and front panel, not changing the audio path further).

But I gather in more recent models it's only semi-direct? Disables processing modes and EQ, but leaves bass management and delays? Or at least optionally?

Although that was always possible anyway, via the separate EQ and surround mode settings - so I'm not quite sure what the distinction is then supposed to be. It used to avoid analog-to-digital or DSD-to-PCM conversion to go through the DSP path but presumably now doesn't always?

Some of those older receivers had an analogue LPF subwoofer output for Direct mode, as a semi-substitute for the DSP crossover. But the real crossover requires going through the DSP path.
 
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Blew

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Don't know about Yamaha, but historically in Denon+Marantz, "Direct" turned off all processing on the signal path, except gain controls. So it ruled out bass management. (And "Pure Direct" just shut off extra circuitry like video processing and front panel, not changing the audio path further).

But I gather in more recent models it's only semi-direct? Disables processing modes and EQ, but leaves bass management and delays? Or at least optionally?
The "Crossovers" page in the manuals linked doesn't mention the crossover not being available in Direct or Pure Direct modes. The "Pure Direct playback" page also doesn't mention Crossovers as one of the items in the list of items that cannot be adjusted in those modes.
Eg https://manuals.marantz.com/nr1711/eu/en/GFNFSYuttunruh.php

So if the manual is accurate then it appears that the crossover function is unaffected by the Direct and Pure Direct modes. It would be great if this is the case.
Although that was always possible anyway, via the separate EQ and surround mode settings - so I'm not quite sure what the distinction is then supposed to be. It used to avoid analog-to-digital or DSD-to-PCM conversion to go through the DSP path but presumably now doesn't always?
The EQ functions are mentioned as not being available in Direct and Pure Direct modes. They may be a separate function entirely.
Some of those older receivers had an analogue LPF subwoofer output for Direct mode, as a semi-substitute for the DSP crossover. But the real crossover requires going through the DSP path.
Perhaps this is still the case?
 
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Blew

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Here's a list of some amps and preamps with proper support for subwoofers:
That's a really handy list, thanks.

The Marantz M-CR611 and M-CR612 (and perhaps others) integrated network receiver CD players also support this. Eg:

Also, apparently it's configurable in the Yamaha R-N803D via the app:
 

sigbergaudio

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The "Crossovers" page in the manuals linked doesn't mention the crossover not being available in Direct or Pure Direct modes. The "Pure Direct playback" page also doesn't mention Crossovers as one of the items in the list of items that cannot be adjusted in those modes.
Eg https://manuals.marantz.com/nr1711/eu/en/GFNFSYuttunruh.php

So if the manual is accurate then it appears that the crossover function is unaffected by the Direct and Pure Direct modes. It would be great if this is the case.

The EQ functions are mentioned as not being available in Direct and Pure Direct modes. They may be a separate function entirely.

Perhaps this is still the case?

Yes, the subwoofer + crossover are still active in pure direct on those Marantzes, the Audyssey room calibration is not.
 

KMO

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So if the manual is accurate then it appears that the crossover function is unaffected by the Direct and Pure Direct modes. It would be great if this is the case.
Would it be great? Why? This is what I don't get. Are we just trying to get the front panel to say "DIRECT" to make the user feel good, or is it actually performing some distinct function?

How is "going through the DSP, no EQ, no upmix, bass management, front panel says DIRECT" different from "going through the DSP, no EQ, no upmix, bass management, front panel says MULTI CH IN"?

Is it running at a higher sampling rate, perhaps? 192kHz rather than 96kHz?

How do you get the analogue pass through if you want it? Does it quietly turn the analogue pass through on and off without telling you depending on Large/Small speaker settings?

I note that the replacement DACs in the current reworked Denons can't do DSD any more, and those units will still say "DSD DIRECT" despite the fact they must be converting to PCM rather than sending DSD direct to the DAC.

So there is an increasing trend for all the "DIRECT" displays to be marketing only - just rather random function enables and disables - not actual distinct signal paths.

Trying to figure this out for myself - I know exactly what all the signal paths are in the old 4308-era Denons, and they made sense. The current receivers are not making sense to me.

Perhaps this is still the case?

Could be, but I don't think so. On the 4308, it was a "Subwoofer on/off" setting in "surround parameters" that appeared only in "Direct" and "Pure Direct" modes. But it's not a crossover, just the LPF.
 

restorer-john

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Why wouldn't other stereo amps have something similar to this function? Is there something that I'm missing?

Because stereo amplifiers are full range products designed to drive full range speakers. If people want to enhance the bottom end, use a powered subwoofer with its own filter. Some integrateds offer a mono sub output (like Yamaha) for people with small speakers.
 

KMO

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Because stereo amplifiers are full range products designed to drive full range speakers.

Nice bit of positive marketing spin :) Look at our "full-range" products, unlike our competitors' "limited-range" products... :D

And we don't ask you set your speakers to "Small", thus threatening your self-image. ;)
 
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Blew

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Would it be great? Why? This is what I don't get. Are we just trying to get the front panel to say "DIRECT" to make the user feel good, or is it actually performing some distinct function?
Because I would like to use it in Pure Direct mode for the cleanest signal path, but would like to use a subwoofer with the stereo speakers at the same time. I will probably use an external DAC instead of the internal one too.
How do you get the analogue pass through if you want it? Does it quietly turn the analogue pass through on and off without telling you depending on Large/Small speaker settings?
I assume that this setting is purely a UX thing. ie it's to prevent people from complaining that their stereo speakers don't sound bassy enough when they turn on the subwoofer setting.
So there is an increasing trend for all the "DIRECT" displays to be marketing only - just rather random function enables and disables - not actual distinct signal paths.

Trying to figure this out for myself - I know exactly what all the signal paths are in the old 4308-era Denons, and they made sense. The current receivers are not making sense to me.
Probably a discussion for this thread: https://www.audiosciencereview.com/...entations-benefits-issues-and-thoughts.13864/
 
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Blew

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Because stereo amplifiers are full range products designed to drive full range speakers. If people want to enhance the bottom end, use a powered subwoofer with its own filter. Some integrateds offer a mono sub output (like Yamaha) for people with small speakers.
The point is to not only enhance the bottom end but also reduce vibrations in standmount speakers. It's the integrated receivers that offer sub output with an adjustable crossover setting that I'm interested in.
 

rwortman

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If you go to preamp/amp instead of integrated and don’t mind using pro audio amps you can do the crossover to the main speakers with the amp.
 
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Blew

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If you go to preamp/amp instead of integrated and don’t mind using pro audio amps you can do the crossover to the main speakers with the amp.
Pro audio meaning professional? ie expensive?
 
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