low pass and high pass filter

[NHT]

Im a bit confused as to how to set this. Whats the difference between low pass and high pass? Should I set them to the same? And what should I set my sub xover? Should I set one 60 and the other 80? thanks

[soundhound]

Low pass means bass passes through to be heard, High pass means midrange and high frequencies pass through and will be heard. Normally you will set these to what sounds best in youre listening enviroment with your'e speakers. You probably dont want to set them to leave a void, example sub at 60 , others at 100, because the 61 to 99 hz frequencies will be discarded and you will hear this. They should be set the same, sub at 100, others at 100 or even cross them a little (sub at 100, others at 80) so you dont leave a hole in what you hear. It primarily depends on your'e speakers and the room they are in.

[NHT]

But if I set the sub at 80 and others at 100, wont there be a gap between 81-99? Or should I just play it safe and set them all the same?

[Azeke]

But if I set the sub at 80 and others at 100, wont there be a gap between 81-99? Or should I just play it safe and set them all the same?

NHT,

Experimentation is the key and your acoustical environment sets the tone. It is what is termed as "tweaking". After experimenting for a prolonged period of time, this is what works best for me, and may provide a baseline for you.

Sub: 80 xover
Fronts: 60 xover
All other speakers: 80 xover

**All speakers set to small in a 7.1 channel environment.

Your mileage may vary of course.

Hope this helps,

Azeke

[Kevin D]

Also keep in mind that the filters are not a brick wall! It could be very easy for the best combo to be separated! The filters are sloped at 24db per octive I believe.

For a real world example, say my main speakers have to be closer to the wall then optimal and I've got an abnormal boost in the 60-80hz area. Then my sub has to go in the corner getting a coupling effect that boosts the 60-80hz area too. By setting the lowpass on the sub to 60 and the high pass on the mains to 80, the slope down from 60-80 on the sub and the slope down from 80-60 on the mains will help level out the sound and blend both together better.

The opposite can be true too! If I have a lull in the 60-80hz area, overlapping them might make help make up for it. Like Azeke said, experiment and see what works best for you.

Kevin D.

[Aussie Geoff]

NHT (and others),

I think there is some confusion here about the functioning of the crossover settings with the Rotel RSP-1098/1068 and RSX-1067/1056...

Let me (try to) clarify by quoting from thje RSP-1098 manual and then explaining further:

SUBWOOFER SETUP menu
Subwoofer Crossover

This setting specifies a master low-pass filter for the subwoofer and a corresponding highpass filter for all SMALL speakers in the system at the selected frequency.

I.E If you set it to (say) 80 Hz then, the default setting for a SMALL speaker will be to have bass below 80 Hz progressively cut off (the 80 Hz setting is a -3 dB point) and transferred to the subwoofer. This cut-off is done by high pass filter. The subwoofer will have a matching low pass filter to cut off sound about 80 Hz, with again 80 Hz being the -3 dB point so that the two signals added together are 0 Db (the baseline level).

ADVANCED SPEAKER SETUP Menu
Crossover

Typically, the RSP-1098 uses a single master setting for the high-pass and low-pass crossover point between all SMALL speakers and the subwoofer. This master crossover point is set on the SUBWOOFER SETUP menu described in the following section. When you first access the ADVANCED SPEAKER SETUP menu, the current master crossover point will be shown on this line. Change the value of this line only if you want the current speaker to have a different crossover point. For example, if your master crossover is set to 80Hz, but you want your front speakers to crossover to the subwoofer at 60 Hz, you would select 60Hz for the front speakers on this line. This setting ONLY affects redirected bass and does not affect the LFE channel in any way. The OFF setting (available only for the subwoofer) sends a full-range signal to your subwoofer so that you can use its built-in low-pass filter.

I.E. If you change the Crossover setting for a speaker pair (e.g. the fronts) to 60 Hz then this affects the high pass filter for those speakers and the matching low pass filter for the sub when processing sound from those speakers. (I.E. Each pair of speakers can have a different high and low pass filter for the subwoofer and the processor’s bass management sorts this out.

Both these approaches – the master default crossover and the speaker override crossover setting employ matching high and low pass filters to avoid any holes or boosts to the sound.

You can create an artificial hole or boost to the sound between two bass frequencies by using the Processor crossover OFF setting for the Subwoofer, and then using a different crossover setting for the speaker in the processor and on the actual physical Subwoofer itself. However I would not recommend Crossover OFF for the Processor Subwoofer setting as means that every speaker must have the same crossover frequency as your subwoofer or you will get problems.

99.9% of the time you get the best results by letting the Processor control the high and low filters and having the actual crossover on the subwoofer itself disabled (or using a special LFE input). For subwoofers that don’t have either option – then you set the actual crossover subwoofer to as high as it will go (say 160 Hz) so that the Processor (operating at say 80 Hz) is controlling the bass (little sound at 160 hz would actually get to the subwoofer!)

Geoff

[ajpoe]

:roll: :T

[NHT]

geoff. That was very well put but to a novice like me, is a bit too confusing and technical. To make it easier, given my system components, what would you recommend my settings be set at?

[Aussie Geoff]

NHT,

Sorry! Here is a simpler (but less complete) explanation:

With the SUBWOOFER Crossover setting the Rotel will set a matching high and low pass filter at the selected frequency for the subwoofer and all SMALL speakers. You can override this for a specific type of speaker (e.g. FRONT, SURROUND etc) using the ADVANCED SPEAKER menu and changing the hih pass crossover setting for that type of speaker, with the subwoofer low pass crossover setting changing to match each speaker.

From your profile your have B&W CDM7-NT(mains) B&W CDM-CNT B&W CDM1-NT(surrounds).

So you could try either:

All speakers SMALL and subwoofer at 80 Hz and leave everything unchanged. This is the THX standard setting that most movies are mixed for. If you use the Analogue inputs from your CD player (if you have one) then you may want to make the FRONT speakers LARGE for STEREO using the ADVANCED SPEAKER menu. This will allow pure stereo listening.

All speakers SMALL and subwoofer at 80 Hz and change only the FRONT speakers crossover to 60 Hz using the ADVANCED SPEAKER menu. Again you could make them LARGE for STEREO. Some people find better bass for music in this situation when they have full range speakers like yours.

Try both - listen and you will know what works for you

Geoff