LFE & sub crossover question

Hi bobnegi,

The simplest, is to select "large" for your fronts, and then use line level (RCA) outputs for the left and right channels to your Velodyne (turn the SUB output OFF). This routes all bass and LFE to front L & R. If you don't have any line level outs on your Yamaha receiver, you can build some out of 3 resistors. PM me if you wanna make some speaker-to-line level converters. Your Wharfdales may enjoy having their load lightened below 50Hz. One way you could try is to STUFF THE PORT. This will improve the transient response and reduce excursion below the new f(-3) frequency of the "sealed" version. My guess is that you'll get a low end cutoff of 45Hz to 70Hz. These are essentially "free" mods, except for the stuffed animals you cram into the ports (my friend uses stuffed OLIVES, if you can picture a green plushie football the size of a NERF).



Martin

Just out of curiosity, how did you arrive at setting the x-over at 50Hz? In my experience, picking the right crossover setting can be a matter of trial and error to get the flattest bass response. Is this in a 2.1 or 5.1/7.1 system?

Scott

Why not set the sub's crossover to it's highest available crossover point?

If you set the sub to crossover at 120hz or so, the sub will attenuate frequencies above 120 hz and output those below that point.
The receiver (being set at 90hz) will only attempt to send frequencies below 90hz to the sub.

The frequencies between 90hz and 120hz will be sent to your main speakers as before, as will all frequencies above 120hz.
Anything below will go to the sub.

If you set your sub at 50hz while the receiver is set at 90hz, the frequencies between 50hz and 90hz will be attenuated.

Ummmm... first of all, your speakers do *not* go to 20 Hz. Their response is -6 dB @28 Hz. The tune point is 30 Hz.
http://www.wharfedale.co.uk/model.php?model_id=16
This means they are down 12+ dB at 20 Hz and are clearly not "full-range" speakers. (Don't get me wrong, these are great spec's for any speaker, but they don't make your speakers into great "subwoofers".) Add to this the fact that the best in-room position for imaging purposes for direct radiators is well away from the side and back walls, (which is the *worst* possible position for bass reinforcement), and your speakers appear to be even less attractive for really deep bass response.

If you set your speakers to "Large", you will be sending them a "full range" signal. Since they are not "full-range" speakers and they are probably not placed for optimal deep bass response, anything below their LF extension, (the tune point of 30 Hz) will be attenuated significantly. However, if you set them to "Small" the lowest bass will be re-routed to the sub and not "lost" or attenuated. Assuming that your sub is the best speaker in your system to reproduce the lowest bass, your best bet is to set your speakers to "Small" and allow the 90 Hz crossover to re-route the lowest bass to the sub.

Then set the sub's crossover to it's highest setting, (or turn it off). You do not want redundant crossover filters in the system, as they will cause phase anomalies and frequency response problems. Let your receiver's Bass Management do it's job.

In the future, you may benefit from a more capable Bass Management system in an upgraded receiver. More flexibility in the crossover, speaker size, distance and level settings may be helpful also. For now, optimize what you have to work with.

Craig

I am currently using a Pioneer 816 receiver and with a tuning point of 40hz, I have my main speakers set to large. My crossover is set to 80 hz. Most film soundtracks are mixed for an optimal crossover at 80hz which is why THX recommends it. But you may need to experiment with that. Craig and I have a slight disagreement on the subject of what is considered "full range" when it comes to speaker settings. I believe if a speakers provides reasonably good output down to 40hz or so, setting the speakers to large will often provide the best results. (See link to an article on this subject below.) I also use a Velodyne subwoofer and also implement the subs crossover due to the fact that most of the Velo ported subs use a high pass filter with only a 6db slope. If your Velo is ported, it's manual may mention that using both crossovers and staggering the settings (ie; 120 sub/80 receiver) my render better performance, meaning cleaner output and reduced port noise at higher volume levels. You really need to play with all these settings in order to find the best results, which are dependent on your particular set up and listening tastes. Good luck!

http://www.hometheatersound.com/feat...c_20010701.htm

Ian

If your mains are set to Large, either they are playing all of the bass that goes to those channels (the sub can probably do it better unless you have a weak sub). If the bass from the mains goes to the sub and the mains, then you have the possibility of double the bass at some frequencies, cancellation at others, etc. Plus, at loud volumes the sub will probably drown out any straining the speakers are doing. And you need a pretty hefty amp to really push full-range speakers at 40hz or lower. A 100wpc receiver probably isn't up to the task to do it justice.

Seriously, what's the problem with crossing over the mains, even if they go lower? The sub is (usually - if not, get a better sub) much more capable of doing bass below 80Hz. Plus, crossing over the mains takes the strain off the amp, giving you more headroom, and takes the strain off the drivers in the mains so higher frequencies are potentially clearer and with less distortion.

Set your mains to "Small", this is not a bad thing, they will handle higher frequencies better that way. Now set the crossover dial on your sub (low pass) to Max. This way you won't lose any bass. You don't have that many options with your receiver since it allows only a fixed crossover. I would stay away from taking speaker level outputs into the sub and then setting crossovers that way. Another option is to buy an external crossover like the Marchand offerings.

The other argument is that by setting the mains to large, you would have less localization issues and you would be reducing the load on the sub. It all depends on the equipment you are using, your room size, acoustics etc... and how your speakers interact with all the above. I can not make it any clearer, you need to experiment to see which way sounds the best.



I quess they just don't make full or (near full range speakers) like they use to.


Ian

Or, they just make subs (and movies) now like they didn't used to.

To be honest with you, I have auditioned a lot of speakers lately and because I was in the whole sale end of this business, I could get some very good deals on them. I just rebuilt my old highly rated Advent 5002's because there really isn't anything that I could find that I would trade them for.

Ian

It always comes down to what sounds the best in your room. I've run staggered crossovers before with good result. I now have what I suppose are considered full range fronts, Polk SDA 1Cs, FR 15hz-26khz, though I doubt the bottom spec, probably they are down 10db at 20hz. Anyway, they sound best run large with direct sources, MCH and 2 channel, but I cut them at 60hz for DD and DTS.

Wow, these?
http://www.polksda.com/sda1c-studio.shtml
Very cool.

What receiver are you using now? Still the HK?
Did you get outboard amplification for those?

So what you're your saying Ron, is that you switch just your crossover setting when listening to DD&DTS formats?


Ian

Brian, yep, with the wooden caps (dark oak, I believe). I'm using the HK as a pre/pro. The SDAs are 6 ohm and need a ton of juice. I temporarily used a 2 channel Audiosource amp, but it just didn't do them justice. I'm found another vintage piece, a Carver TFM 35 on the bay for a reasonable price. It's 250 wpc @ 8ohms and has the nuts to drive them. Happy to have you over if you want to listen...very nice. I just swapped out my surrounds for John's Mordaunts yesterday, another big improvement. The only thing left is the center.


Pretty much Ian...The HK handles each source with differing crossovers except 6/8 channel direct. My player handles the crossover @ 80hz for 5.1 MCH and none for 2 channel direct, which is how I do a lot of listening now.

Very cool. I'd love to check them out.
I've been drolling over the Emotiva LPA-1, which is 125w x 6 for $499.
AV123 used to sell them, until Emotiva started selling direct.


I need to have you and JG over some time.
I'll have a pair of x-ls pretty soon, too, if you want to hear them.

Sounds like you got a new player. What did you end up with?
Sounds like those speakers do fine without the 20-39+ (?) for music, too!
Nice.

PM'd you

That's a great feature to have. You get the best of both worlds. When I listen to two channel direct I implement my outboard eq and then have to change my settings accordingly.

Ian