[dbelon]

The consensus here seems to go with setting all speakers small in a 5.1 system. I am using front towers capable of fairly low bass. My receivers crossover is set to 60 hz. I recently added a second sub, however I'm still finding it hard to set my fronts to small. I feel like I'm not using my fronts to their full potential if I set them small. Should I set all speakers to small despite my concerns? Thanks.


Dennis

 

[BlueDude]

Don't think of it as not using your fronts to their full potential. Think of it as freeing your fronts (and their associated amps) to roar in their best range. Setting your fronts to small will put the LF load on the sub where it belongs and free up amp headroom to drive your fronts easier.


Besides all that, if you choose to run your fronts full range, you're going to have a devil of a time getting them to play nicely with two subs. That's four LF sources all interacting and sometimes competing and nullifying each other. Optimizing two subs is hard enough without trashing their calibration with a couple more "wild" sources in the same space.

 

[spyboy]

Hi Dennis


I have a pair of mains that are flat to 35Hz. I have used them full range with my HSU VTF-3HOs + Turbos. I did not have any integration problems at all.


Then I decided to use the Small setting on my receiver. It may be slightly better with all of the speaker set to Small, but not very much of a difference.


The points made by BlueDude are valid. I would try crossing over your speaker at 80Hz, and see how you like that.


All the Best

 

[dbelon]



Quote:
Originally Posted by BlueDude /forum/post/0


Don't think of it as not using your fronts to their full potential. Think of it as freeing your fronts (and their associated amps) to roar in their best range. Setting your fronts to small will put the LF load on the sub where it belongs and free up amp headroom to drive your fronts easier.


Besides all that, if you choose to run your fronts full range, you're going to have a devil of a time getting them to play nicely with two subs. That's four LF sources all interacting and sometimes competing and nullifying each other. Optimizing two subs is hard enough without trashing their calibration with a couple more "wild" sources in the same space.

Good point. What about the crossover? Is the THX 80 hz standard better for blending speakers set to small. Thanks.


Dennis

 

[BlueDude]

A good rule of thumb is to set the crossover for a speaker at about double the -3dB point, or about 80Hz, whichever is lower. (Much higher than 80Hz might cause the bass to be localized). So if your mains are good down to 30Hz, try a crossover of 60Hz. Rules of thumb aside, the best setting is the one that sounds best to you. There's nothing particularly magical about 80Hz, other than that it's usually a good compromise setting.


Things get complicated if you have a global crossover vs. a per channel crossover. Then you might have to put the crossover higher than you might otherwise to keep the surrounds or center channel from being crossed too low and creating a hole. It might be possible that the best setting would be 60Hz on the mains, 80Hz on the center, and 100Hz on the surrounds, for instance. If you only have one setting, you might have to compromise and put them all at 80Hz or even 90Hz. I wouldn't worry too much about filling every hole in the surrounds since you probably won't miss anything there, but you might be bothered by low voices coming from the corner of the room, which is a possibility if your center channel crossover is set too high.


Good luck!

 

[dbelon]

Since both my subs employ a 24dB/octave fourth-order Linkwitz-Riley crossover it appears the 80 hz THX crossover point would be best. I'll give it a try. It just seems like I'm not using my mains (Dynaudio Audience 82s) to their full potential. I suppose a more seamless sub/mains integration overrides this concern however.


Dennis

 

[mailiang]

If you set your mains to large, you will only direct bass to the sub from the lfe channel when listening to 5.1 audio tracks. Regardless of how well your mains can handel most of your bass, in most cases the sub will do it better. Therefore either set your mains to small or your bass management to plus. You may need to experiment to see which way provides the best results.


Ian

 

[BlueDude]



Quote:
Originally Posted by dbelon /forum/post/0


Since both my subs employ a 24dB/octave fourth-order Linkwitz-Riley crossover it appears the 80 hz THX crossover point would be best. I'll give it a try. It just seems like I'm not using my mains (Dynaudio Audience 82s) to their full potential. I suppose a more seamless sub/mains integration overrides this concern however.

If I were you, I'd defeat the crossover in the subs (or turn up the cutoff frequency as high as they'll go) and let your receiver, or pre-pro, or whatever you're using for bass management handle all the crossover duties. You can get some odd effects if you have more than one crossover at work. Even if they were exactly matched, you would have two LPF's at work you'd effectively have a 48dB/octave filter.


As to your concern that you're not using your mains to their full potential, you are. The crossover HPF isn't a brick wall and you'll have plenty of content coming from your mains below the cutoff frequency. You're just gradually offloading mains and their amp onto the sub and its amp, leaving headroom to spare for 95% of your mains' frequency range, where it excels. Low frequency reinforcement uses a LOT of power, but that's a job for your subs' amps, which are likely more powerful for a single driver than any two channels and multiple drivers on your main amp. The freed power on your main amp means you have more headroom for transients while your sub amps handle slam. Besides all that, your main amp will run cooler and last longer. You're not actually giving anything up - just allocating power where it does the most good.


Besides, look on the bright side. For critical listening, your receiver or pre-pro probably has a direct mode which disables bass management - and your subs. You can then use the full range of your mains without any other configuration changes, and still reap the benefits of sub reinforcement with home theater. That to me sounds like the best of both worlds without compromises.

 

[mailiang]



Quote:
If I were you, I'd defeat the crossover in the subs (or turn up the cutoff frequency as high as they'll go) and let your receiver, or pre-pro, or whatever you're using for bass management handle all the crossover duties. You can get some odd effects if you have more than one crossover at work. Even if they were exactly matched, you would have two LPF's at work you'd effectively have a 48dB/octave filter.

This theory assumes that you already have a 24db slope. However most HTR's only use a 12 db slope. Under certain circumstances, you may get better results also using your subs crossover, but stagger the settings (ie:120/80) for a steeper slope, which in some cases may provide you with cleaner over all output.


Ian

 

[dbelon]

Actually, I do have my subs crossovers bypassed so I guess their filter slopes are irrelevant. In any case I tried the 80 hz setting and it was okay, however I think I prefer the 60 hz receiver crossover with mains set to large. Jury is still out on sub mode LFE vs LFE + mains. Getting the speakers and sub setup calibrated properly can be tricky since the changes are subtle in most cases.

Dennis

 

[BlueDude]

I'm a little bit confused, since with the mains set to large, the crossover setting is irrelevant, at least for the mains. What do you have for surrounds and center that require a x-o of 60Hz? Those have to be some serious surrounds.


Anyway, the ultimate setting is what sounds best to you. Sounds like you have a winner!

 

[dbelon]



Quote:
Originally Posted by BlueDude /forum/post/0


I'm a little bit confused, since with the mains set to large, the crossover setting is irrelevant, at least for the mains. What do you have for surrounds and center that require a x-o of 60Hz? Those have to be some serious surrounds.


Anyway, the ultimate setting is what sounds best to you. Sounds like you have a winner!

Thanks for the advice. I'm still experimenting with configurations but I think the best crossover for my system is 60hz. My center and surrounds are flat down to at least 50hz. I have also finally accepted the logic behind setting all speakers to small and letting the subs do what they were designed for. Thanks again for the input.


Dennis

 

[foamfan]

I feel your pain; just recently went through the same pains after acquiring my new speakers and avr.


For my purposes, It seems like the best settings for both music and HT were a 40 Hz crossover for the subwoofer and my fronts set on large managed by my avr. This setting was really appreciable on the normal listening or viewing area.


When I am not in my normal listening area and roaming around the house; I leave my fronts set at large but set the sub crossover at either 60 Hz or 80 Hz (slightly inferior to 60 Hz but more workload is done by subwoofer at this setting).


Now why on earth will someone ever do this? I work/stay at home and use my sound system sometimes up to 18 hours a day (average about 12-14 hours/day) and I want to put as little wear on the woofer as possible. These settings work well for me and I hope you find what works best for you.