Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Dual Velodyne DD+ subwoofers
#1
Hi!

My system is Devialet 400 with Radio XT-1 speakers and Velodyne DD10+.
I've just bought another Velodyne DD10+ subwoofer. Anyone else using these with Devialet and would like to share their setup?
The Velodyne manual recommends "daisy chan" making one master and one slav sub, but with the devialet there is also
a possibility to connect one subwoofer to each devialet.

Best regards Johan
Squeezebox Touch (digital mod) with linear PS - Audioquest Eagle Eye - Devialet 400 - DFPC signature PC - Tellurium Q Ultra Black - Raidho X-1
Reply
#2
Subwoofer frequency range is on 99.9% of recordings mono (the exception are some rare recordings of classical music), but I still use stereo connection on Devialet - just in case, for these 0.1% Smile

On the other side, almost all optimizations I've done on subwoofers (phase, low-pass filter, gain, PEQs...) are aimed mainly to both subwoofers together - as mono.
Devialet Expert 440 Pro | Anthem MRX 720
Dynaudio Confidence 50 | Dynaudio Excite X28 | Dynaudio Emit M20 | 2x SVS SB16-Ultra
LG OLED 77 CX | LG OLED 65 C7



Reply
#3
Delija isn't quite correct.

The subwoofer range may not be mono on 99.9% of recordings because the subwoofer range is variable. It depends on the crossover frequency chosen. Studies have shown that most people are unable to detect the source of sounds below 80 Hz. That means that if you set your crossover frequency at 80 Hz or below, you will probably not be able to detect the source location of the sounds reproduced by the subs but I use two subs in my HT system (a different system to my audio system and located in a different room) and been able to detect the location of one of the subs because the sub was in a corner and strongly loaded a room mode at a frequency below 80 Hz and I was able to detect that that sub was in the corner when the sub was reproducing loud sounds at that modal frequency though I could not detect its location at other times. If you set the crossover at 80 Hz or lower you should rarely be able to notice the difference between 2 subs operating together in mono and 2 subs operating in stereo mode but it may be possible to do so at some times depending on the location of the subs and how each sub loads the room's modal frequencies.

Is it worth using the subs with a stereo connection rather than using them with a mono signal? That's going to depend on where you place the subs and where your listening position is located, plus on the frequency content of the signal going to the subs from moment to moment. Most of the time there should be no significant audible difference, perhaps even all of the time depending on the bass content of the music you're playing and whether or not your room modes coincide with the frequencies of any musical notes. The times when I could tell that one of my subs was located in a corner wasn't with musical notes, it was with sound effects noises like explosions, earthquakes and so on, which were noises with broad band low frequency content that didn't coincide with the frequencies of the notes occurring in the music content of the soundtrack.

I can't say that you will never notice a difference but you may. If you are going to try using 2 subs in stereo mode then the best advice would be to locate them close to the speakers so that the sound from each sub arrives at a very close angle to the sound from their associated speaker. The problem with that is that not only is that placement not likely to deliver the best bass performance the subs are capable of, it's that multiple subs are normally used to help smooth out the modal behaviour of rooms at low frequency and placing the subs close to the speaker is unlikely to result in a smoothing of the low frequencies over a wider listening area. In fact, if you have noticeable room modes with your current speakers when using them full range without a sub, placing a pair of stereo subs close to the speakers is likely to exacerbate the modal problems you notice without a sub.

In short you may notice some small, occasional benefit from using 2 subs in stereo but it's also possible that 2 subs in stereo might make any existing low bass problems worse. It also requires more work to balance the sound of 2 subs in stereo with your speakers than it does to balance the sound of a mono pair of subs with your speakers. You may find yourself having to do a lot more work to get a good result with stereo subs for very little overall improvement and if you have modal frequencies that coincide with musical notes you may even make things worse. I've tried a stereo sub setup in my HT system with good results but it took a lot of work and it was a fidgety process. In the end I went back to having the 2 subs operating together in mono. It was a lot easier to set them up in mono and any difference in sound quality or imaging was negligible to non-exsistant in my setup. You're more likely to notice a difference between stereo and mono subs if your crossover frequency is set above 80 Hz, especially if it's set at 120 Hz or higher because you're using main speakers with very limited bass capability and/or your room is large and getting good bass down to 80 Hz or preferably lower is presenting too much demand on your amplifiers since the bass frequencies are where the amp has to work hardest.
Roon Nucleus+, Devilalet Expert 140 Pro CI, Focal Sopra 2, PS Audio P12, Keces P8 LPS, Uptone Audio EtherREGEN with optical fibre link to my router, Shunyata Alpha NR and Sigma NR power cables, Shunyata Sigma ethernet cables, Shunyata Alpha V2 speaker cables, Grand Prix Audio Monaco rack, RealTRAPS acoustic treatment.

Brisbane, Qld, Australia
Reply
#4
I don't see what part of my post is not correct...

Sound directivity is irrelevant if the original recording (frequency range of interest) is mono - both channels are recorded or mixed the same. As I've already said, 99.9% of recordings has mono bass usually up to ~150 Hz. That's high enough above usual crossover frequency - which is very rarely above 80 Hz - and considering 24 dB/oct slope of low-pass filter which is usually used. In stereo systems crossover is pretty often lower than 80 Hz.
Devialet Expert 440 Pro | Anthem MRX 720
Dynaudio Confidence 50 | Dynaudio Excite X28 | Dynaudio Emit M20 | 2x SVS SB16-Ultra
LG OLED 77 CX | LG OLED 65 C7



Reply
#5
The part that is incorrect is the bit about 99.9% of the subwoofer range being in mono. That's probably the case if you limit the upper frequency of the subwoofer range to around 80 Hz but many people run their subs to higher frequencies than that because they're using speakers which start rolling off at frequencies of 80 Hz or higher. In practice it's the user who limits the subwoofer range when they set the crossover frequency so it's the user who determines the subwoofer range, not the subwoofer manufacturer or the recording engineer who mixes the recording.

In your response you said "As I've already said, 99.9% of recordings has mono bass usually up to ~150 Hz" but that is not what you originally said. What you originally said was "Subwoofer frequency range is on 99.9% of recordings mono (the exception are some rare recordings of classical music)" and you did not specify an upper frequency for subwoofer range. I'm not certain that recording engineers do mix to mono up to around 150 Hz. What they seem to do on a lot of the music I listen to is to mix instruments like electric or double bass and the bass drum into the centre of the sound stage so that all frequencies from them are in mono but with some other instruments like the piano which goes about half an octave lower than the bass the instrument including the bass notes seem to be mixed to an off centre location so their bass isn't present in mono. That's another reason I'm not certain that 99.9% of low bass is mixed to mono, a lot certainly is but definitely not all of it in my experience.

As I said, it is occasionally possible to determine the location of a sub because it is loading a room mode strongly, something corner placement does though other locations can also strongly load a room mode. If a mode is strongly loaded at a particular frequency then the sub can reveal itself as a separate sound source and you can locate it even though the mode being loaded occurs below 80 Hz. Also as I said, in my experience of a few occasions on which this has occurred, it has happened with loud low frequency sound effects in a soundtrack rather than with music so it may not be relevant in the OP's case but under the right combination of frequency content in the recording and a strong activation of a modal frequency by the sub, the sub location can be identified. This has not been common in my experience but it has definitely occurred on a small number of occasions and it isn't related to the directionality of low frequency sound, it's simply because some low frequency sound effects in movies are essentially the bulk of the sound when they occur so the sub or subs are the only speakers really working when some sounds occur and that can make it easier to locate the sub just from the volume level of the sound since there are no frequencies in the sound being reproduced by other speakers which are high enough in frequency to provide the normal directional cues. This is probably not a problem if you're only using your system for playing music but if it's also doing double duty for HT work the sub may occasionally identify itself as a source of the sound.
Roon Nucleus+, Devilalet Expert 140 Pro CI, Focal Sopra 2, PS Audio P12, Keces P8 LPS, Uptone Audio EtherREGEN with optical fibre link to my router, Shunyata Alpha NR and Sigma NR power cables, Shunyata Sigma ethernet cables, Shunyata Alpha V2 speaker cables, Grand Prix Audio Monaco rack, RealTRAPS acoustic treatment.

Brisbane, Qld, Australia
Reply
#6
(04-Aug-2020, 05:23)David A Wrote: The part that is incorrect is the bit about 99.9% of the subwoofer range being in mono. That's probably the case if you limit the upper frequency of the subwoofer range to around 80 Hz but many people run their subs to higher frequencies than that because they're using speakers which start rolling off at frequencies of 80 Hz or higher. In practice it's the user who limits the subwoofer range when they set the crossover frequency so it's the user who determines the subwoofer range, not the subwoofer manufacturer or the recording engineer who mixes the recording.

I would say it's far from "many people". If we are talking about Hi-Fi sistems, and we are, it's minority, but @Atomjohan is really one of them Smile, since Raidho X-1 has pretty limited FR on lower side. I expected it goes lower than 80 Hz, but I was wrong - I just looked at the specs.

In his case, yes, he should use stereo subwoofer output on Devialet, since crossover must be higher than 80 Hz to get flat response in crossover area.
Of course, this makes sense only if his subwoofers are positioned close to main speakers - in stereo configuration and not in e.g. diagonal corners of the room.


(04-Aug-2020, 05:23)David A Wrote: ...but with some other instruments like the piano which goes about half an octave lower than the bass the instrument including the bass notes seem to be mixed to an off centre location so their bass isn't present in mono. That's another reason I'm not certain that 99.9% of low bass is mixed to mono, a lot certainly is but definitely not all of it in my experience.

Nope. The perception of "stereo" bass comes from upper harmonics. It's really very easy to test this - turn off one of your subwoofers, and the bass will still be "stereo".


(04-Aug-2020, 05:23)David A Wrote: As I said, it is occasionally possible to determine the location of a sub because it is loading a room mode strongly, something corner placement does though other locations can also strongly load a room mode. If a mode is strongly loaded at a particular frequency then the sub can reveal itself as a separate sound source and you can locate it even though the mode being loaded occurs below 80 Hz. Also as I said, in my experience of a few occasions on which this has occurred, it has happened with loud low frequency sound effects in a soundtrack rather than with music so it may not be relevant in the OP's case but under the right combination of frequency content in the recording and a strong activation of a modal frequency by the sub, the sub location can be identified. This has not been common in my experience but it has definitely occurred on a small number of occasions and it isn't related to the directionality of low frequency sound, it's simply because some low frequency sound effects in movies are essentially the bulk of the sound when they occur so the sub or subs are the only speakers really working when some sounds occur and that can make it easier to locate the sub just from the volume level of the sound since there are no frequencies in the sound being reproduced by other speakers which are high enough in frequency to provide the normal directional cues. This is probably not a problem if you're only using your system for playing music but if it's also doing double duty for HT work the sub may occasionally identify itself as a source of the sound.

This should not be the case even with mono configuration with two subs (if they are not on the same place - stacked, of course). The fact that LFE in movies is always mono is not even important for this.

One case that crosses my mind would be low quality subwoofer with bad housing which vibrates and produces higher frequency "parasite" sounds.
Devialet Expert 440 Pro | Anthem MRX 720
Dynaudio Confidence 50 | Dynaudio Excite X28 | Dynaudio Emit M20 | 2x SVS SB16-Ultra
LG OLED 77 CX | LG OLED 65 C7



Reply
#7
@Delija

You said "Nope. The perception of "stereo" bass comes from upper harmonics. It's really very easy to test this - turn off one of your subwoofers, and the bass will still be "stereo"."

I did say that the cues for stereo localisation occurred at frequencies above 80 Hz. When I said I could, on a very few occasions, identify low frequencies as coming from one sub it was not because of the upper harmonics, it was because of a single low frequency peak which was significantly louder than the sound coming from the speakers or from the other identical sub which is in a different location, actually close to a speaker, with the subs running in mono. Normally, even with loud LFE effects in the bass frequencies, the source of the bass does not appear to come from the sub. If it were a problem due to vibration of the sub's housing producing higher frequencies I should notice it with both subs since they're identical and I don't notice the other sub. The other sub is closer to a shelving unit with various objects upon it which are occasionally excited into vibration which is easily identified. What I'm talking about is a strong peak in volume due to a room mode being excited because of the location of that particular sub. In the end I moved it a couple of feet to a location where it does not load the room mode in the same way and stopped noticing that behaviour. That would confirm my assertion that it is possible, under the right combination of circumstances, to identify the location of a sub because if the cause of the behaviour was as you suggested moving the sub to a different location would not have eliminated the problem.
Roon Nucleus+, Devilalet Expert 140 Pro CI, Focal Sopra 2, PS Audio P12, Keces P8 LPS, Uptone Audio EtherREGEN with optical fibre link to my router, Shunyata Alpha NR and Sigma NR power cables, Shunyata Sigma ethernet cables, Shunyata Alpha V2 speaker cables, Grand Prix Audio Monaco rack, RealTRAPS acoustic treatment.

Brisbane, Qld, Australia
Reply
#8
Cut to the chase...
(I should have written this in my first post Smile)

Since Devialet has stereo subwoofer output - it should be used, especially with speakers like Raidho X-1 which have pretty limited FR on lower side.
But in order to have gains of this setup, subwoofers should be positioned accordingly - in stereo configuration, near the main speakers.

This is how I use subwoiofers in my system...

[Image: IMG-20200221-220953.jpg]
Devialet Expert 440 Pro | Anthem MRX 720
Dynaudio Confidence 50 | Dynaudio Excite X28 | Dynaudio Emit M20 | 2x SVS SB16-Ultra
LG OLED 77 CX | LG OLED 65 C7



Reply
#9
Nice system and setup.
Roon Nucleus+, Devilalet Expert 140 Pro CI, Focal Sopra 2, PS Audio P12, Keces P8 LPS, Uptone Audio EtherREGEN with optical fibre link to my router, Shunyata Alpha NR and Sigma NR power cables, Shunyata Sigma ethernet cables, Shunyata Alpha V2 speaker cables, Grand Prix Audio Monaco rack, RealTRAPS acoustic treatment.

Brisbane, Qld, Australia
Reply
#10
Thank you, friend!
Devialet Expert 440 Pro | Anthem MRX 720
Dynaudio Confidence 50 | Dynaudio Excite X28 | Dynaudio Emit M20 | 2x SVS SB16-Ultra
LG OLED 77 CX | LG OLED 65 C7



Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)