Jonathan M
Second Unit
- Joined
- Jul 23, 2002
- Messages
- 267
Hi All,
As promised, I analysed the bass management using a method I developed to measure it's frequency response over the weekend.
It was quite successful, and I was able to easily verify that the NAD acts like one would presume it should under most conditions.
For a start, the manual is incorrect. It states in the manual that with the sub on, and mains set to large, then any bass from other channels set to small is sent to both the sub and the mains. This is incorrect (Luckily!) and the bass gets sent ONLY to the sub which is good news. (No bass doubling.)
I have measured the frequency response of a number of different scenarios and have concluded the following:
High pass xovers on channels set to SMALL are at the specified xover frequency (If using a sub) OR at 100Hz (If no sub is present). They are 2nd order Butterworth filters.
Low pass xover for any filtered bass is a 4th order Linkwitz Riley aligned xover at the xover frequency mentioned above. This is per the THX spec, I believe.
The above applies to ALL digital sources. The LFE channel (If present) is boosted by 10dB relative to the other bass, before being mixed and sent to the sub, as it should be. I'm pretty sure that the LFE channel is not filtered in anyway before being sent to the sub (As it is already filtered on mastering) but I will have to confirm this.
Analog sources do not have any bass management on them, unless they are being processed by a DSP. ie. they are analog direct - just passing through the volumea and tone control (If in place) circuitry.
If the sub is set to ON, then a summed signal that is low passed at around 500Hz (I will confirm this later) at around 1st or second order is sent out the subwoofer pre-out. If the sub is off, then nothing is sent down the sub channel. The mains receive a full bandwidth signal - regardless of whether they are set to LARGE or SMALL.
The best plan for people with this receiver is to use digital only inputs as much as possible so all bass management is effected. If you must also use analog inputs, then you may either apply a DSP to them, or do the bass management for the mains externally via the pre-out/main-in loop.
I am just checking over my measurements over the next week or so, and will hopefully be posting a website with info including graphs of the frequency response etc. including how anyone can perform these same tests.
If anyone has any questions - feel free to ask.
As promised, I analysed the bass management using a method I developed to measure it's frequency response over the weekend.
It was quite successful, and I was able to easily verify that the NAD acts like one would presume it should under most conditions.
For a start, the manual is incorrect. It states in the manual that with the sub on, and mains set to large, then any bass from other channels set to small is sent to both the sub and the mains. This is incorrect (Luckily!) and the bass gets sent ONLY to the sub which is good news. (No bass doubling.)
I have measured the frequency response of a number of different scenarios and have concluded the following:
High pass xovers on channels set to SMALL are at the specified xover frequency (If using a sub) OR at 100Hz (If no sub is present). They are 2nd order Butterworth filters.
Low pass xover for any filtered bass is a 4th order Linkwitz Riley aligned xover at the xover frequency mentioned above. This is per the THX spec, I believe.
The above applies to ALL digital sources. The LFE channel (If present) is boosted by 10dB relative to the other bass, before being mixed and sent to the sub, as it should be. I'm pretty sure that the LFE channel is not filtered in anyway before being sent to the sub (As it is already filtered on mastering) but I will have to confirm this.
Analog sources do not have any bass management on them, unless they are being processed by a DSP. ie. they are analog direct - just passing through the volumea and tone control (If in place) circuitry.
If the sub is set to ON, then a summed signal that is low passed at around 500Hz (I will confirm this later) at around 1st or second order is sent out the subwoofer pre-out. If the sub is off, then nothing is sent down the sub channel. The mains receive a full bandwidth signal - regardless of whether they are set to LARGE or SMALL.
The best plan for people with this receiver is to use digital only inputs as much as possible so all bass management is effected. If you must also use analog inputs, then you may either apply a DSP to them, or do the bass management for the mains externally via the pre-out/main-in loop.
I am just checking over my measurements over the next week or so, and will hopefully be posting a website with info including graphs of the frequency response etc. including how anyone can perform these same tests.
If anyone has any questions - feel free to ask.