Using double subwoofer hook-up to bypass crossover

The place to sound off on all things related to audio, from sound cards to speakers.

Moderator: Captain Ned

Using double subwoofer hook-up to bypass crossover

Postposted on Sat May 04, 2013 1:08 pm

Hello,

I had a bit of a problem. When initially calibrating my receiver, a Yamaha RX-V665, I noticed that the center (Canton GLE 455) and surround channels (GLE 430) had a bit of a gap between, say 65hz and 80hz when setting up the receivers internal crossover to 60hz. When raising the crossover to 80, they sounded quite a bit better, with a more even soundfield and more "depth" in the centre channel (more oomph on impacts and low male voices...). However, at 80hz, my mains (Canton GLE 490's towers) simply lacked the deep low end they had before. The overall bass volume was about the same, but I could clearly hear the deep bass tones coming from the subwoofer. (A Yamaha NS-SW500)
I learned to live with this, frequently shifting between a 60hz crossover for music and a 80hz crossover for movies.
-
Eventually, it got old.
So I went to my local HiFi store and asked around for a solution.
One option was to buy a receiver that allowed me to set a different crossover point for each speaker.
Sadly, none of the receivers on display was capable of such a feat. (Or the salesmen simply didn't know which one could do this.)
-
So I came up with an alternate plan: I hooked up my GLE 490's directly to the subwoofer with speaker cables, and changed those speakers to LARGE in the menu of my receiver (the other speakers were kept at small).
I then changed the subwoofers crossover to 55hz, which to my ears sounded like the sweetspot for mains.
I also raised the receiver's crossover to 90hz, which is what the GLE 455 center is rated at (-+3dB).
I kept the SUB-OUT of my receiver enabled, but switched the RCA cable from MAIN IN to LFE only, as the manual of my sub stated that this bypasses whatever internal crossover is set on my subwoofer (55hz), so that the receiver could still send the full LFE + BASS of the center and surround channels.
-
After hooking all of this up and playing around with the SUB volumes both on the receiver and the SUB itself a bit (measuring the output level per channel with a tone sweep) I finally found the sweet spot for my system.
The only question now remaining is this: is it actually okay to feed my subwoofer two signals at once? Can the internal electronics cope with running both speaker wire (Mains) and a RCA cable (LFE+ Bass out)?
For now everything seems and sounds fine, but I just want to make sure that what I've cooked up is going to be okay in the long run.
The subs manual didn't really specify this, so I'm kind of curious if any of you have tried something similar in the past?
I7-3770@4ghz, Asus P8H77-M, NVIDIA 780 GTX, 16 gig DDR3-800 Kingston, 1x Samsung 840 EVO 512gb SSD, 2x 3000GB 7200rpm SATA WD Black, Lite-on Blu-ray 16x DVD+-RW, X-fi Titanium HD, Corsair 550D Obsidian.
Asus UX31E with i5 and 256gb SSD.
havanu
Gerbil
 
Posts: 91
Joined: Tue Oct 26, 2004 6:45 pm

Re: Using double subwoofer hook-up to bypass crossover

Postposted on Sat May 04, 2013 4:56 pm

havanu wrote:The only question now remaining is this: is it actually okay to feed my subwoofer two signals at once? Can the internal electronics cope with running both speaker wire (Mains) and a RCA cable (LFE+ Bass out)?

Yes, this is safe. The sub will have the intelligence built-in to permit it to select between the two inputs (powered output from the receiver and line level). It will pass the amplified outputs to the main stereo speakers, and will use the signal you select as it's source for the subwoofer's driver. If you tell it to use the mains, it will sample that signal and then amplify it. If you tell it to use the RCA (line level), it will amplify that signal. Either way, the dedicated amp in the sub is what's connected to the sub's driver.

What you can't do, and should never do, is to connect the output of two separate amplifiers to a single point (unless they're specifically designed for it).
This problem was caused by Windows, which was created by Microsoft Corporation.
sluggo
Gerbil Jedi
Gold subscriber
 
 
Posts: 1536
Joined: Wed Feb 16, 2005 8:44 pm
Location: under the table and dreaming

Re: Using double subwoofer hook-up to bypass crossover

Postposted on Sat May 04, 2013 5:09 pm

Isn't that what sort of what I'm doing here? The 'Large' mains run through the speaker input on the sub while the receiver sends the LFE+ bass out from the remaining 'small' speakers through RCA. So they both play at the same time to a single output, like you stated, namely the sub.
It sounds good, but I'm just worried i might be running the sub in a way that might be stressful for the amp inside.
I7-3770@4ghz, Asus P8H77-M, NVIDIA 780 GTX, 16 gig DDR3-800 Kingston, 1x Samsung 840 EVO 512gb SSD, 2x 3000GB 7200rpm SATA WD Black, Lite-on Blu-ray 16x DVD+-RW, X-fi Titanium HD, Corsair 550D Obsidian.
Asus UX31E with i5 and 256gb SSD.
havanu
Gerbil
 
Posts: 91
Joined: Tue Oct 26, 2004 6:45 pm

Re: Using double subwoofer hook-up to bypass crossover

Postposted on Sun May 05, 2013 1:34 am

When I said a "single point", I meant just that. The RCA inputs on your sub and the high level speaker inputs on your sub are not a single point. They're two inputs separated (inside the sub cabinet) either by a relay or a couple of high-impedance buffer stages, or both. The manufacturer has to build the product to allow for the sort of wiring situation you describe, and so they do.
This problem was caused by Windows, which was created by Microsoft Corporation.
sluggo
Gerbil Jedi
Gold subscriber
 
 
Posts: 1536
Joined: Wed Feb 16, 2005 8:44 pm
Location: under the table and dreaming

Re: Using double subwoofer hook-up to bypass crossover

Postposted on Sun May 05, 2013 3:00 am

Okay, thank you for clearing that up.
I'm glad Yamaha makes this possible on their hardware, although I'm baffled why they don't have this kind of setting in their receivers setting. I'm pretty sure I'm not the only one with a setup where the mains are far more capable then the other speakers.
Surely a seperate crossover for each speaker can't be that hard to implement on hardware in that pricerange?
I7-3770@4ghz, Asus P8H77-M, NVIDIA 780 GTX, 16 gig DDR3-800 Kingston, 1x Samsung 840 EVO 512gb SSD, 2x 3000GB 7200rpm SATA WD Black, Lite-on Blu-ray 16x DVD+-RW, X-fi Titanium HD, Corsair 550D Obsidian.
Asus UX31E with i5 and 256gb SSD.
havanu
Gerbil
 
Posts: 91
Joined: Tue Oct 26, 2004 6:45 pm

Re: Using double subwoofer hook-up to bypass crossover

Postposted on Sun May 05, 2013 4:20 am

Pretty sure the more expensive receivers offer this feature, along with auto-calibration stuff like Audeyssey or YPAO in Yamaha's case.

The lack of pre-outs is anothing thing I find really annoying. I'm sure it wouldn't be too expensive to implement, but in many cases it's only available in the more expensive receivers. Nuts because if anything, it's the amp section that's a huge differentiating factor for higher-end receivers. Basically they're saying you have to buy a higher end receiver with better amps, in order to be given the option to NOT use the built-in amps. :roll:
jihadjoe
Gerbil Team Leader
 
Posts: 248
Joined: Mon Dec 06, 2010 11:34 am

Re: Using double subwoofer hook-up to bypass crossover

Postposted on Sun May 05, 2013 4:29 am

Well, my reciever has Pre-outs, 5 HDMI's in's, 2 toslink in's, it even has multichannel analog inputs (!) and YPAO, it just doesn't offer seperate crossovers for each speaker. It was a 500€ receiver at the time (+-3 years old).
I recently checked out the Yamaha RX-V673, one of their best selling receivers at the moment, as a replacement for my V665, and it also doesn't have this setting.
I've heard DENON's have had this for years, perhaps this is something Yamaha should look into.
Last edited by havanu on Tue May 28, 2013 4:41 pm, edited 1 time in total.
I7-3770@4ghz, Asus P8H77-M, NVIDIA 780 GTX, 16 gig DDR3-800 Kingston, 1x Samsung 840 EVO 512gb SSD, 2x 3000GB 7200rpm SATA WD Black, Lite-on Blu-ray 16x DVD+-RW, X-fi Titanium HD, Corsair 550D Obsidian.
Asus UX31E with i5 and 256gb SSD.
havanu
Gerbil
 
Posts: 91
Joined: Tue Oct 26, 2004 6:45 pm

Re: Using double subwoofer hook-up to bypass crossover

Postposted on Mon May 06, 2013 11:03 am

I have an RX-V473 and the lack of individual speaker crossover options are just as annoying there, too. Along with the lack of pre-outs.

But regardless, the better solution for your situation is to upgrade the center-channel. Most dialogue and quite a few on-screen effects are routed through the center yet it is often selected to be much smaller than the mains for cost savings or aesthetic reasons, which does nothing good for the soundfield.

As a side note, I about choked on my coffee when I saw the frequency response range on those Cantons. I hope they build some exceedingly good boxes and crossovers, because those lower roll-offs are pretty weak tea for what those units typically cost.
He who laughs last, laughs first next time.
ludi
Gerbil Elder
 
Posts: 5407
Joined: Fri Jun 21, 2002 10:47 pm
Location: Sunny Colorado front range

Re: Using double subwoofer hook-up to bypass crossover

Postposted on Mon May 06, 2013 12:04 pm

I think you might actually be attenuating some of your audio signal in your current setup. If I'm understanding it correctly, you're telling your receiver that your mains are full range speakers so the full spectrum of those channels is going out over those powered outputs, but you're then attenuating anything below 55hz via the subwoofer crossover. You're then using the LFE output to pick up the lower range frequencies from your center and surround channels but your receiver wouldn't be sending the low frequency info from the main L and R channels (because it's sending those to the speaker outputs). Now, maybe your receiver has a feature like my pioneer call "bass plus" or something like that where the low frequency from the main channels is sent to both the speakers and the sub, but I don't see that specifically called out. I think as much attention as you're paying to crossover frequencies you'll want to be sure you're getting all that information as well.

I think the solution might be fairly simple if I'm understanding it all correctly - I think you can tell your receiver that you don't have a subwoofer, leave the mains set as large, and drive the sub from the line-level inputs of the main channels that should also get the LFE information from the surround and center channels as the only "large" speaker in the system. I think that should work.
i7-3770K | Asus P8Z77-V LK | 8GB DDR3-1600 | HD5850 | 128GB 840 Pro | Samsung F3 1TB | U2412M | Define R4 | Seasonic 520W M12II | Win7 Pro x64.
frumper15
Gerbil Team Leader
Silver subscriber
 
 
Posts: 236
Joined: Mon Jan 18, 2010 3:25 pm

Re: Using double subwoofer hook-up to bypass crossover

Postposted on Mon May 06, 2013 12:20 pm

Hello Frumper,

Double bass (LFE + Front) is not selected. I tried it for a while, didn't like it. It made my Fronts way to bass heavy compared to the other speakers.
-
Setting the Fronts as "Large" and turning off the subwoofer would indeed be a valid option, although I read somewhere that my receiver cuts the LFE by -10dB when it sends that signal to the Front instead of the sub, thus making the whole endeavor pointless for any real LFE workout (Since both the normal redirected bass and the LFE channel will both be send to the Sub hooked up to the Front LR channel, and the LFE channel will have less volume compared to the normal Bass).
I might be wrong about the 10dB cut, but then again it would make sense, as Dolby Digital specifically demands an extra 10dB dynamic range for LFE channels so that discrete channel has more volume headroom (95dB vs 105dB, if I'm not mistaken...).
-
Mmmh, I'm going to try your suggestion and run a few Inception loops of the bathtub scene while measuring the Sub's response with and without your suggestion implemented. I'll keep you posted.
I7-3770@4ghz, Asus P8H77-M, NVIDIA 780 GTX, 16 gig DDR3-800 Kingston, 1x Samsung 840 EVO 512gb SSD, 2x 3000GB 7200rpm SATA WD Black, Lite-on Blu-ray 16x DVD+-RW, X-fi Titanium HD, Corsair 550D Obsidian.
Asus UX31E with i5 and 256gb SSD.
havanu
Gerbil
 
Posts: 91
Joined: Tue Oct 26, 2004 6:45 pm

Re: Using double subwoofer hook-up to bypass crossover

Postposted on Mon May 06, 2013 1:30 pm

I think the OP's way of circumventing a receiver that doesn't allow you to set different crossover points for each channel is pretty elegant and sounds to be doing exactly what they want in theory. The only issue is how the subwoofer handles two simultaneous bass signals. It should be safe enough though. I say, if it sounds good, then keep doing it.

But shame on Yamaha. My $500 Denon AVR from 2008 has the option to set different crossover points for each channel. Though it's still missing pre outs at that level.
cynan
Gerbil Elite
Gold subscriber
 
 
Posts: 804
Joined: Thu Feb 05, 2004 2:30 pm

Re: Using double subwoofer hook-up to bypass crossover

Postposted on Mon May 06, 2013 4:01 pm

Ludi,
I agree on the center channel. It's really weird, the surrounds can actually go down to about 70 Hz without any loss of bass. But the GLE455 center speaker cuts out really early at +-3 dB@80-90Hz.
I'd love to have a third GLE 490 for the center channel, but I'd then have to lay it down on it's side to make it fit my setup, something that will surely be frowned upon by the majority of my audio-geeky friends. Using a different brand of speaker seems odd to me. Surely the sound would be quite different and not really matching the mains in timbre, would it?
And besides the somewhat lacking low-end, the center speaker actually doesn't sound all that bad. The tweeter and dual 6 inch woofers can handle dialogue quite well, with the sub taking care of the low end.
-
Frumper15, I reread your post and finally understood what you were trying to say. The sub isn't actually attenuating anything. It's just rerouting anything the mains receive below 55Hz to it's own driver. So in theory nothing of the spectrum is lost. I still like your suggestion to disable the sub altogether in the receiver's menu, so the mains(+sub) receive all the bass. It's more elegant somehow, if the 10dB reduction of LFE proves to be false, that is, since that way ALL of the bass above 55Hz is played through the Fronts as well, even the bass from the centre/surrounds. It's worth a shot anyhow.
-
Cynan, I wish I had your Denon. I'm not even using the Pre-outs or the analog multi-channel-in anymore, but I'd kill for a crossover per channel.
-
Gentlemen, this has been a fun discussion. Thank you for your contributions.
I7-3770@4ghz, Asus P8H77-M, NVIDIA 780 GTX, 16 gig DDR3-800 Kingston, 1x Samsung 840 EVO 512gb SSD, 2x 3000GB 7200rpm SATA WD Black, Lite-on Blu-ray 16x DVD+-RW, X-fi Titanium HD, Corsair 550D Obsidian.
Asus UX31E with i5 and 256gb SSD.
havanu
Gerbil
 
Posts: 91
Joined: Tue Oct 26, 2004 6:45 pm

Re: Using double subwoofer hook-up to bypass crossover

Postposted on Mon May 06, 2013 4:40 pm

I may have gotten lost in the fog, but it's my understanding that LFE content is present only in theatrical-release mixes. That is, when listening to redbook audio, there is NO signal present at the receiver's LFE output. Nothing. Connecting that output labeled LFE to a subwoofer means that you are not using it at all when listening to the typical CD or other stereo content. It's also my understanding that LFE content is not typically subject to user-adjustable crossovers. It simply is what it is. Is that not the case?

If, in addition to treating theatrical LFE content correctly, the receiver also takes low-frequency content from any active source and gains it up and then sends it out the LFE channel, then you have a receiver that's trying to make the most of what's attached, but it's behavior needs to be fully defined for the owner/user, like in a manual or something. A receiver that does this is not performing to any standard, and it's implementation is defined only by the manufacturer. Does your Yamaha receiver's manual describe what it's trying to do when you set your crossover point? Is the crossover active only for redbook audio or is it also modifying the LFE content?

Disclaimer: I have not bought any multi-channel audio gear in 20+ years.
This problem was caused by Windows, which was created by Microsoft Corporation.
sluggo
Gerbil Jedi
Gold subscriber
 
 
Posts: 1536
Joined: Wed Feb 16, 2005 8:44 pm
Location: under the table and dreaming

Re: Using double subwoofer hook-up to bypass crossover

Postposted on Mon May 06, 2013 4:50 pm

Hello Sluggo,

You are right about the LFE, of course. But my setup is meant to play both movies as well as music. So the Mains are hooked up to the sub to provide smoother lowend below 55Hz and the other speakers are hooked up to the sub via RCA, controlled by the receiver, to provide a smoother low-end below 90Hz. The only reason I'm mentioning LFE is that the LFE-in on my Sub bypasses the Sub's own crossover (that the Mains use) and when I'm playing a film, a full LFE signal (0-120Hz) will be present alongside the receivers' crossover mixdown of the center+surround channels.
However, If I were to turn off the dedicated SUB-out and send all of the BASS+LFE to the mains, my receiver would cut any LFE content by about 10dB, as this is the gain that most receivers apply to the dedicated LFE-out because of some special Dobly specification.
-
I admit, it's quite a complicated setup. But it works. I think. :)
I7-3770@4ghz, Asus P8H77-M, NVIDIA 780 GTX, 16 gig DDR3-800 Kingston, 1x Samsung 840 EVO 512gb SSD, 2x 3000GB 7200rpm SATA WD Black, Lite-on Blu-ray 16x DVD+-RW, X-fi Titanium HD, Corsair 550D Obsidian.
Asus UX31E with i5 and 256gb SSD.
havanu
Gerbil
 
Posts: 91
Joined: Tue Oct 26, 2004 6:45 pm

Re: Using double subwoofer hook-up to bypass crossover

Postposted on Mon May 06, 2013 5:02 pm

Sluggo - My understanding of the situation is that formats like Dolby Digital and DTS have dedicated 5.1 or 7.1 audio channels where the .1 is the LFE or bass track that is specifically sent to the correct speakers. However, receivers also have a crossover frequency (most of the time 80 hz) that below which the audio information below that level in the other speakers (center, surround, mains, etc) is also routed to the sub so those smaller speakers do not waste energy trying to produce sounds they are unable to. Likewise, playing audio that doesn't include a dedicated LFE track (ie. music) will also send plenty of sound to the sub via the aforementioned crossover frequency function.

havanu - your sub must be different than ones I've owned if it is able to accept input from both the LFE input (RCA input on my subs) and the Line level (speaker connectors) at the same time. If that is the case, it would appear that you would be getting all the audio info contained in your source material the way you have it hooked up. I think it should also work with just the line levels hooked up and telling your system you have no sub. I'm not sure what that does for audio between your sub crossover (55hz) and your speaker crossover (90hz) - I guess they'll be output by the main speakers instead of the sub. I don't think you should have any problem with localizing the sound at those low frequencies, but you may have surround channels coming through your mains (as opposed to the sub through the LFE).

It sounds like you've got the tools and ability to work this out for your room and setup. I would agree that a center channel with lower range might be the silver bullet to get the sound you're going for, especially in movie applications.
i7-3770K | Asus P8Z77-V LK | 8GB DDR3-1600 | HD5850 | 128GB 840 Pro | Samsung F3 1TB | U2412M | Define R4 | Seasonic 520W M12II | Win7 Pro x64.
frumper15
Gerbil Team Leader
Silver subscriber
 
 
Posts: 236
Joined: Mon Jan 18, 2010 3:25 pm

Re: Using double subwoofer hook-up to bypass crossover

Postposted on Mon May 06, 2013 5:09 pm

Actually, looking at the manual for the sub, it's very doubtful that the sub includes a low-cut filter on its high-level speaker outputs (in all likelihood the terminals are just paralleled) . So the OP would be running his mains without a low-cut filter, which may not be the end of the world.
i5-750 @ 3.3 GHz; Asus P7P55D-E Pro; Thermalright Silver Arrow; Antec P183; 4 GB; 2x Radeon HD 6950; Corsair HX650.
UltimateImperative
Gerbil First Class
 
Posts: 135
Joined: Sat Sep 19, 2009 12:48 am
Location: The Enn See Arrr, Central-Eastern Canuckisthan.

Re: Using double subwoofer hook-up to bypass crossover

Postposted on Mon May 06, 2013 5:48 pm

havanu wrote:Ludi,
I'd love to have a third GLE 490 for the center channel, but I'd then have to lay it down on it's side to make it fit my setup, something that will surely be frowned upon by the majority of my audio-geeky friends. Using a different brand of speaker seems odd to me. Surely the sound would be quite different and not really matching the mains in timbre, would it?

Right, it's best to match tweeters across the entire front, if not the whole system. Some audio enthusiasts do use a third main as a center channel, but oriented upright. Horizontal speaker arrays tend to be a bit compromised in how they distribute the soundfield, which is why most center channels have a single tweeter (and sometimes a single midrange in a vertical alignment with the tweeter), even though there are usually two woofers to improve the low-end efficiency and frequency response.
He who laughs last, laughs first next time.
ludi
Gerbil Elder
 
Posts: 5407
Joined: Fri Jun 21, 2002 10:47 pm
Location: Sunny Colorado front range

Re: Using double subwoofer hook-up to bypass crossover

Postposted on Mon May 06, 2013 9:01 pm

UltimateImperative wrote:Actually, looking at the manual for the sub, it's very doubtful that the sub includes a low-cut filter on its high-level speaker outputs (in all likelihood the terminals are just paralleled) . So the OP would be running his mains without a low-cut filter, which may not be the end of the world.

I think you're right - the manual doesn't seem to mention anything about a crossover for the outputs, just a high-level cut for what goes to the sub. So, I guess that mean the OP has been running his mains as Large - a.k.a. sending the full range to the mains. The specs say the mains go down to 55Hz or so, so maybe that's not all bad. If you like the sound that you're currently getting, leave the mains set as large, set your receiver to no subwoofer and just adjust your sub level and high level frequency cutoff to your satisfaction.
i7-3770K | Asus P8Z77-V LK | 8GB DDR3-1600 | HD5850 | 128GB 840 Pro | Samsung F3 1TB | U2412M | Define R4 | Seasonic 520W M12II | Win7 Pro x64.
frumper15
Gerbil Team Leader
Silver subscriber
 
 
Posts: 236
Joined: Mon Jan 18, 2010 3:25 pm

Re: Using double subwoofer hook-up to bypass crossover

Postposted on Tue May 07, 2013 12:39 am

I always assumed a high cut filter was some sort of crossover, with a -albeit- rather steep slope and all.
I7-3770@4ghz, Asus P8H77-M, NVIDIA 780 GTX, 16 gig DDR3-800 Kingston, 1x Samsung 840 EVO 512gb SSD, 2x 3000GB 7200rpm SATA WD Black, Lite-on Blu-ray 16x DVD+-RW, X-fi Titanium HD, Corsair 550D Obsidian.
Asus UX31E with i5 and 256gb SSD.
havanu
Gerbil
 
Posts: 91
Joined: Tue Oct 26, 2004 6:45 pm

Re: Using double subwoofer hook-up to bypass crossover

Postposted on Tue May 07, 2013 10:19 am

havanu wrote:I always assumed a high cut filter was some sort of crossover, with a -albeit- rather steep slope and all.

I think the high cut filter is a crossover, but just the opposite of what you might be thinking - it's attenuating high frequencies from going to the sub rather than low frequencies going to speakers (like your receiver is doing).
i7-3770K | Asus P8Z77-V LK | 8GB DDR3-1600 | HD5850 | 128GB 840 Pro | Samsung F3 1TB | U2412M | Define R4 | Seasonic 520W M12II | Win7 Pro x64.
frumper15
Gerbil Team Leader
Silver subscriber
 
 
Posts: 236
Joined: Mon Jan 18, 2010 3:25 pm

Re: Using double subwoofer hook-up to bypass crossover

Postposted on Tue May 07, 2013 10:28 am

That makes perfect sense. I'm also glad to report that my speakers sound pretty much the same with or without the "SUB" enabled in the settings. There's a slightly wider sound field when changing Bass+LFE -out from "SUB" to "Front" in the receiver but that's it. So it appears that both options are equally valid.
Hell, even YPAO correctly configures every speaker, levels and crossover correctly when I run it now, with or without "LFE+Bass=SUB".
So I'm a happy camper.
I7-3770@4ghz, Asus P8H77-M, NVIDIA 780 GTX, 16 gig DDR3-800 Kingston, 1x Samsung 840 EVO 512gb SSD, 2x 3000GB 7200rpm SATA WD Black, Lite-on Blu-ray 16x DVD+-RW, X-fi Titanium HD, Corsair 550D Obsidian.
Asus UX31E with i5 and 256gb SSD.
havanu
Gerbil
 
Posts: 91
Joined: Tue Oct 26, 2004 6:45 pm


Return to Echo Vale

Who is online

Users browsing this forum: No registered users and 0 guests

cron