Sub Crossover Freq and DTS / DD

[Airpirate CVG]

I have a Sub with a crossover that ranges from 50Hz - 200Hz where should it be set for Dolby Digital and DTS formats? I have been told it should be set @ 50Hz at least for 2 channel audio is this also true for HT? Note Sub is hooked to the preamp Sub output and LFE is set for both mains and sub.

Yamaha HT Receiver

Mains: RF3

Center: KV1

Rear: RS3

Sub: JBL

[Soundthought]

Go ahead and crank it up a bit.

What i like to do is overlap the top end of my subs with the bottom end of the speakers quite a bit.

The RF3s bottom end is rated at 37Hz, so it probably starts rolling off around 50/60Hz.

I would probably set the crossover on the sub up an octave around 90Hz.

From that point, I would sample plenty of familiar source material and fine tune it to my liking.

Ultimately, experimentation is the best device for aquiring the sound your striving for. IMHO.

But then again, this is coming from a guy who can't even set a toaster.

Have fun with it!

[boa12]

ap, your yammy already filters the sub through the sub out beginning at 90hz. however for LFE

it sends that only to the sub out/sub.

so if you don't want to cut LFE you should turn the sub's crossover all the way up to like 120hz or disable the sub's crossover if it has a switch for that. if the bass sounds muddy w/ the "both" setting in the yammy & fronts set large, you may want to set the fronts to small. most it seems have found that's the best way to go even w/ big front speaks, so that the sub & fronts don't interfere so much w/ each other covering the same freq range.

[Detroit Kid]

Audioreality,

Why would the RF-3 start rolling off at 50-60Hz if the low freq is 37Hz? What kind of effect do you get with the overlap (sub crossover set at 90Hz)?

[TheEAR]

Detroit Kid,

37Hz is the lower usable limit of the speakers,the speakers are not linear down to 37Hz.SO they start rolling off around 50-60Hz.Any speaker will have weaker and weaker output as soon as frequency extremes are aproached.

[Soundthought]

Detroit Kid,

The tolerance of the specification,

37Hz-20kHz +/-3dB tells me that the speaker will barely be able to satisfy the given specs.

This is very normal for most average, practical loudspeakers.

The right amount of overlapping allows for better transition between the loudspeaker and the sub.

I believe it also help smooth out bass response.

So live, love and overlap.

[boa12]

dk, if you're asking me, i suggested not using the crossover on the sub. that's because w/ the sub-out hookup as above all LFE goes only to the sub & its speced to 120hz or higher. i just don't like the idea of cutting any info in the LFE channel myself.

& the yammy uses a 90hz fixed cross for the low bass that goes to the sub if you choose like a both setting in the receiver. your sony uses a 80hz fixed crossover. the same 90hz or 80hz is used as a fixed high pass to your other speakers when you set them to small.

iow, don't use the crossover on the sub. that's really still there for the old 2-channel days before they came up w/ LFE.

these days the receiver or pre/pro handles the crossovers digitally. & the best allow you to change the crossover point such as to a lower freq to better accomodate for big speaks & a sub.

f.e., if you play some 2-channel music & you run your rf-3 on large it will put out pretty good from 40hz on up. but your sub will also be putting out the same from that 40hz on up to 80 or 90hz. this overlap can give you poorer quality & uneven bass w/ the standing waves, peaks, nulls (destuctive interference).

but maybe some like the peaks & don't notice any nulls. different rooms. tastes, etc. have to experiment w/ the various settings to find out for sure, & that's after you have things placed right.

i've just found that the bass is tighter & cleaner not overlaping too much. i set all speaks small & the adjustable crossover at 50hz in the pre/pro so that's where the sub starts getting cut on up & the speaks start getting cut on down. but i still had to experiment to find where it sounds best overall for all material.

w/ your fixed 80hz cross in the sony, all you have to do is switch the fronts back & forth between large & small w/ some 2-channel, bassy material to hear which sounds better.

[Detroit Kid]

boa, So, if I set the sub crossover to 120hz or cut it off altogether and set the speakers to small, won't I have overlap between 80-120hz when listening to music? Will that have the muddled sound you are talking about? I can't test it yet...should have the RF-3s around Christmas and the sub will come after that.

Thanks!

[boa12]

dk, some overlap between the sub & speakers is inevitable. the key is the transition between them. if you set the fronts to small the sony starts rolling off those channels' low bass (not the LFE) from the rf-3 gradually at 80hz on down in freq & at the same time the sub starts rolling off the same low bass (not the LFE) at 80hz on up in freq. this is what they call crossover slopes. & this is done in the receiver.

by turning the sub crossover all the way up or disabling it, you're in effect not using the sub's crossover & letting the receiver do it instead. this is what thx, dolby & dts all have in mind for 5.1 material.

[Airpirate CVG]

Thanks for the tips. I am still a little dissapointed with the RF3's bass performance at least with 2 channel. It really thunders in HT. I was raised on JBL L100 Studio Series that needed no sub those things would break windows on their own. The Rf's don't seem to produce the bass in 2 channel like my KG4's did either. Seems without a sub or the bass cranked all the way on the receiver my Rolling Stones and Moody Blues tunes have little bass. Bass seems a plenty only with music with very heavy bass tracks such as hip hop which I do not care to listen to. Oh well maybe I am old school.