Cambridge Audio AXR 100 - 100W Stereo amplifier subwoofer crossover 200Hz, Pros/Cons

[JBL2004_RGXCMBCA]

Cambridge Audio AXR 100 - subwoofer output is specified as - 200Hz 2nd order (L+R ). I am somewhat puzzled by the higher level of the crossover point. What would be the benefit of specifying such a high level for a crossover point? I am also not clear on (2nd Order) terms.

AXR85/AXR100 Manual

techsupport.cambridgeaudio.com

 

[lovinthehd]

It doesn't appear to be a crossover. More likely simply a low pass filter, many integrated amps lack an actual crossover (which would be a combination of low pass filter for the sub and high pass filter for the speakers). Might try this https://www.electronics-tutorials.ws/filter/second-order-filters.html

 

[JBL2004_RGXCMBCA]

It doesn't appear to be a crossover. More likely simply a low pass filter, many integrated amps lack an actual crossover (which would be a combination of low pass filter for the sub and high pass filter for the speakers). Might try this https://www.electronics-tutorials.ws/filter/second-order-filters.html

@lovinthehd, thanks for providing me that insight, I need some time to digest all the details. My next question is , will it be worthwhile to connect an active subwoofer like SVS SB - 1000 to this Amp?

 

[TLS Guy]

@lovinthehd, thanks for providing me that insight, I need some time to digest all the details. My next question is , will it be worthwhile to connect an active subwoofer like SVS SB - 1000 to this Amp?

What this means is that it has half a crossover, in this case a low pass crossover but not a high pass crossover. So a second order crossover at 200 Hz, would be 3 db down at 200 Hz and 15 db down at 400 Hz, and 27 db down at 800 Hz.

Now remember subs have a crossover as well.

Now, the speakers are going to be exposed to a full range signal. That is absolutely fine if they are capable of taking a full range signal without damage or distress, and there are plenty that will. By the same token there are plenty with small wimpy drivers that can't. If you have speakers that can, then what you do is look at the speaker spec, and find the frequency where the speaker rolls off. What you want to know is the frequency at which the speaker is 3db down. Now you add 50% to that number. Say for instance the -3 db point is 40 Hz, then you would set the sub crossover to 60 Hz. If you have good capable speakers, this is actually a very good way of doing bass management and leads to excellent results. If the speakers are not capable then it will not.

There is one more issue. If you use the rig for HT then you will not properly send the LFE signal to the sub, as that signal extends to 120 Hz. The other problem is that these low frequency effects signals are very potent and your other speakers will not be protected from them.

So a system I outlined can work in many cases very well as a music system, but not so well as an HT system unless the main speakers are very robust, and that usually means expensive.

Unfortunately pretty much only AV receivers and pre/processors contain the bass management for most speakers now currently available. This is a major beef of mine. This encourages the wasteful installation of multi channel systems in rooms that are totally unsuited to them. In my view that is the vast majority of rooms. So there is a huge unfulfilled need for units like you are looking at that have modern bass management.

Unfortunately the industry continues to shoot itself in the foot, and wonder why AV remains such a small niche market relatively. I suppose they are content to sell people those ghastly soundbars, and con them into thinking they have surround systems which they don't. The industry is a total mess at the moment, and not providing and guiding the market to a much more enlightened and intelligent approach.

 

[JBL2004_RGXCMBCA]

What this means is that it has half a crossover, in this case a low pass crossover but not a high pass crossover. So a second order crossover at 200 Hz, would be 3 db down at 200 Hz and 15 db down at 400 Hz, and 27 db down at 800 Hz.

Now remember subs have a crossover as well.

Now, the speakers are going to be exposed to a full range signal. That is absolutely fine if they are capable of taking a full range signal without damage or distress, and there are plenty that will. By the same token there are plenty with small wimpy drivers that can't. If you have speakers that can, then what you do is look at the speaker spec, and find the frequency where the speaker rolls off. What you want to know is the frequency at which the speaker is 3db down. Now you add 50% to that number. Say for instance the -3 db point is 40 Hz, then you would set the sub crossover to 60 Hz. If you have good capable speakers, this is actually a very good way of doing bass management and leads to excellent results. If the speakers are not capable then it will not.

There is one more issue. If you use the rig for HT then you will not properly send the LFE signal to the sub, as that signal extends to 120 Hz. The other problem is that these low frequency effects signals are very potent and your other speakers will not be protected from them.

So a system I outlined can work in many cases very well as a music system, but not so well as an HT system unless the main speakers are very robust, and that usually means expensive.

Unfortunately pretty much only AV receivers and pre/processors contain the bass management for most speakers now currently available. This is a major beef of mine. This encourages the wasteful installation of multi channel systems in rooms that are totally unsuited to them. In my view that is the vast majority of rooms. So there is a huge unfulfilled need for units like you are looking at that have modern bass management.

Unfortunately the industry continues to shoot itself in the foot, and wonder why AV remains such a small niche market relatively. I suppose they are content to sell people those ghastly soundbars, and con them into thinking they have surround systems which they don't. The industry is a total mess at the moment, and not providing and guiding the market to a much more enlightened and intelligent approach.

@TLS Guy, Thanks, this setup will be for stereo music , my questions were based on the specs from the AXR 100. I wasn't sure how this configuration works. I have never had a stereo amp with a dedicated x-over before.

So what I understood from your answer was that the AXR 100 would send signals (equal or below) <= 200Hz to the subwoofer and by adjusting the subwoofer x-over point appropriately, that I would be able to take a advantage of this feature.

The two main speakers have following specs,

(Paradigm 700F)
Low Frequency Extension 33Hz
Frequency Response (On Axis) +/-3dB 45 Hz–25 kHz
Frequency Response (30°) +/-3dB 45 Hz–20 kHz
Crossover 2nd-order electro-acoustic at 2.5 kHz, 2nd order electro-acoustic at 800 Hz

Not sure if I should consider 33Hz or 45 Hz since you mentioned the -3 dB, I will use 45Hz, so the Subwoofer x-over will be about 65 - 70 Hz? (67.5)?

your feedback is much appreciated!

 

[TLS Guy]

@TLS Guy, Thanks, this setup will be for stereo music , my questions were based on the specs from the AXR 100. I wasn't sure how this configuration works. I have never had a stereo amp with a dedicated x-over before.

So what I understood from your answer was that the AXR 100 would send signals (equal or below) <= 200Hz to the subwoofer and by adjusting the subwoofer x-over point appropriately, that I would be able to take a advantage of this feature.

The two main speakers have following specs,

(Paradigm 700F)
Low Frequency Extension 33Hz
Frequency Response (On Axis) +/-3dB 45 Hz–25 kHz
Frequency Response (30°) +/-3dB 45 Hz–20 kHz
Crossover 2nd-order electro-acoustic at 2.5 kHz, 2nd order electro-acoustic at 800 Hz

Not sure if I should consider 33Hz or 45 Hz since you mentioned the -3 dB, I will use 45Hz, so the Subwoofer x-over will be about 65 - 70 Hz? (67.5)?

your feedback is much appreciated!

The place to set the sub crossover will be between 60 and 80 Hz, you will need to experiment.

 

[lovinthehd]

@lovinthehd, thanks for providing me that insight, I need some time to digest all the details. My next question is , will it be worthwhile to connect an active subwoofer like SVS SB - 1000 to this Amp?

That integrated amp may not be the best tool to integrate a sub with but, sure, you could hook up a sub and "blend" it using the sub's low pass filter (often mislabeled as a "crossover" on many subs).