Which other points? Aren't they all subsets of sub placement and crossover choices?
The consensus so far seems to be that either the connection type doesn't matter or preamp to sub amp connection is preferred.
Subwoofer connections...what is great and what is not so good.
- Thread starter DaveyF
- Start date
The consensus so far seems to be that either the connection type doesn't matter or preamp to sub amp connection is preferred.
For the past 17 years I have used multi-channel DAC's with active crossovers to the subs. This allows for the following:
- Different high/low pass slopes
- Different delay for subs vs mains
- Infinite crossover frequencies
- Phase correction across integration frequencies
- Stereo bass with the sub/satellite becoming a "full range" speaker or mono bass
- Mains left fullrange with their natural rollof and subs integrated at the rolloff frequency
- Removal for bass frequencies from main signal for greater amp/speaker efficiency
??? Can you tell us more about this? These days, I would use a miniDSP or equivalent.
SPL is determined by driver excursion. Driver excursion is the Sd of the driver (surface area in meters squared) multiplied times 2(X-Max in mm). When the 21" driver and the 4" driver are both "moving the same air" then the SPL will be identical. If the system is calibrated properly, then the SPL of either subwoofer will always stay in the same relationship to the mains until the limits of either the sub system or the mains is reached. A room being overloaded is a function of the room, not the subwoofer.
One thing to consider is that the bandwidth of a larger sub driver will be wider (up to a certain size). The wider bandwidth driver will play lower and, if the content has bass in those lower frequencies, then the wider bandwidth driver is putting more energy into the room. This is sometimes considered increased loading or boomy but is actually accurate playback of the content. Because wavelengths get longer and longer as you go lower in frequency, a wider bandwidth is also sometimes perceived as "slower."
I painstakingly set up active cross-overs for sub-mains (Eidolon Vision + 2 x JL113) integration using a 4 channel Trinnov processor / DACs, and ended up preferring using standard bass-management. In fact, I ended up with running the subs in mono, which worked best in my system.
You can use a miniDSP with multi-channel outputs for just EQ on the subs, but I doubt many want to use it for output for their mains. To add a high-pass to the mains the miniDSP has to do A/D, DSP, and then D/A again. I think it defeats the purpose of using a high quality DAC in the first place.
I have always used a computer as the source and have never owned a pre/pro or receiver. With a computer I have used internal soundcards or external soundcards/DACs. The past 3-4 years I have used pro audio DACs. They have a very high quality to price ratio.
With using the computer as the source, the driving factor becomes the software. I first used the soundcard driver's own features for bass management. Then I used a media player combined with VST plugins for handling bass management and EQ. Finally, JRiver Media Center added its own bass management, PEQ, and advanced routing.
I have a friend that uses two Mytek Stereo192-DSD DAC's for his two-channel system. One Mytek is for the mains and one is for the subwoofers. The Mytek ASIO driver combines both DAC's as one 4-channel DAC. The Exasound multi-channel DAC's are another good option for someone to use with computer playback and have high quality multi-channel output.
I use the Lynx AES16e with AES output to a multi-channel DAC. Theoretically, someone could use it with a high quality 2 channel DAC for the mains and a different DAC for the subs. Both DAC's would obviously need AES input. Since the clock is generated by the AES16e and carried by the AES cable, both DACs will still stay in sync. Any differences in delay would be accounted for during measuring and calibration.
Using multiple subs in mono will almost always give a smoother in-room frequency response with less EQ required. I would recommend anyone using a crossover less than about 60Hz should run the subs in mono. There are times when stereo might be preferred above that.
Why leave the mains full-range? Doesn't that just waste amp and speaker headroom driving them below the sub cut-off?
If I understand correctly, the mains in Mojave's system only get a high pass signal coming out of the computer digitally from the Lynx card, feeding a AES/EBU DAC.
The reasoning for this in general is to avoid whatever signal degradation might occur from having both active and passive crossovers in the signal chain.
That's great. BUT you seem to be implying that the speakon connection and the amp/sub connection method is inferior. Which, I believe IF you were able to set up your sub with that method, you would find the
opposite. Simply because your connector is faulty OR you have not connected the cable correctly at the amp end ( no grounding) doesn't invalidate the set up. BTW, IF you amp is balanced, ( I have an ARC tube amp
that is set up this way...) the connection is NOT the same as suggested in the sub manual. You would again need to talk to Sumiko or the amp manufacturer for their set up recommendation. ( It is VERY odd that
the manual for these subwoofers mentions NOTHING about this issue
From the G series REL manual - it even includes a picture:
Di?erential or Class-DAmpli?er Connection
• For differential (i.e.fully balanced) ampli?ers using one REL,simply use the standard connecting scheme
with the excep1on of connec1ng the black wire to chassis ground (i.e. a metal bolt or screw, preferably
not painted or anodized, on the chassis of the power amp or receiver), not to a negative speaker terminal,
and then connecting into the HIGH-LEVEL INPUT on the REL. Please contact your dealer should there be
any questions concerning this or any other hookup procedure.
Last edited:
I don't do that in my own system. I meant that using multi-channel DAC's allows for that while still providing proper delay adjustment. Some prefer it. What it does is provide more lower bass sources and can smooth the frequency response. However, if you have ported mains, leaving them fullrange can also cause phase interference issues with the subs. Again, I'm not advocated a method. I'm just saying there are multiple methods and the ability to compare once you go to a computer with multi-channel DACs.
Sure, BUT are you seriously trying to tell me that the 4" driver is going to be able to move as much air as the 21" driver? At the same very low SPL's, maybe....BUT things go very different very quickly, as the the SPL's increase. My point being that since the wavelength of a very low frequency is long, the likelihood of being able to reproduce that frequency in a small to medium size room diminishes as the frequency gets lower.
Micro, that's interesting as I do not think that is mentioned in my T5 manual. OTOH, Sumiko were quite responsive to me as to the hook-up protocol with my balanced ARC amp and after I asked them about how to hook up multiple subs.
Thanks. I have begun playing with that approach using jRiver along with exaSound or Mytek DACs and dipping my toe into Dirac. Just groping my way at the moment.
Hi
Working on a project and not able to sleep so ... WBF is the outlet to relax for a while ... Interesting subject: Subwoofers.
I will be blunt, the method of connecting a subwoofer whether from the speaker (High Level) or the preamp (Low Level) is the least important consideration in using a subwoofer.
Anyone with familiarity with speakers with powered woofers/subwoofer will attest that despite the method used the character of the main amps is revealed clearly, the character of an amp remains strong regardless of the method used to connect the subwoofers and since the vast majority of those (audiophiles) using subwoofers feed the subs from the preamp ...
Mojave posts are most important for anyone interested in using a sub. The notion of a overloading a room is not function of the size of a driver. it is true that the size of the driver has some impact on that of the subwoofer enclosure and one may not want the girth of huge subs occupying an already small space. We need to really focus on how to integrate a sub with mains.
To make it short, there are a few methods to use subs. They can be summarized this way.
The mains are run full range or however far they can go with no crossover in line with them to reduce the low to them or the mains amp.
The preamp output is followed by an active crossover that control / limt the amount of bass the mains get/reproduce.
I tend t think that the second method is the least used.
As for recipes to integrate subwoofers with mains. The two methods I know of are the Welti/Dvantier aka Harman method and the Earl Geddes method. They seem to be variant of each other. Geddes goes for quasi random positioning of the subs in the room while the Harman method recommend placement at fixed positions. As for the level , crossover, etc... That is where the difficulties occur .. Not a simple thing and requires knowledge and lot of measurements and yes, listening. Not a simple thing to accomplish. The results are however worth it. properly integrated subs in a system results in vastly superior musical reproduction and that for any type of music: From chamber to hip-hop or elecronica.
Working on a project and not able to sleep so ... WBF is the outlet to relax for a while
... Interesting subject: Subwoofers. I will be blunt, the method of connecting a subwoofer whether from the speaker (High Level) or the preamp (Low Level) is the least important consideration in using a subwoofer.
Anyone with familiarity with speakers with powered woofers/subwoofer will attest that despite the method used the character of the main amps is revealed clearly, the character of an amp remains strong regardless of the method used to connect the subwoofers and since the vast majority of those (audiophiles) using subwoofers feed the subs from the preamp ...
Mojave posts are most important for anyone interested in using a sub. The notion of a overloading a room is not function of the size of a driver. it is true that the size of the driver has some impact on that of the subwoofer enclosure and one may not want the girth of huge subs occupying an already small space. We need to really focus on how to integrate a sub with mains.
To make it short, there are a few methods to use subs. They can be summarized this way.
The mains are run full range or however far they can go with no crossover in line with them to reduce the low to them or the mains amp.
The preamp output is followed by an active crossover that control / limt the amount of bass the mains get/reproduce.
I tend t think that the second method is the least used.
As for recipes to integrate subwoofers with mains. The two methods I know of are the Welti/Dvantier aka Harman method and the Earl Geddes method. They seem to be variant of each other. Geddes goes for quasi random positioning of the subs in the room while the Harman method recommend placement at fixed positions. As for the level , crossover, etc... That is where the difficulties occur .. Not a simple thing and requires knowledge and lot of measurements and yes, listening. Not a simple thing to accomplish. The results are however worth it. properly integrated subs in a system results in vastly superior musical reproduction and that for any type of music: From chamber to hip-hop or elecronica.
Frantz, perhaps we are agreeing on this, BUT I think that your statement needs some clarification. The size of the driver can lead to the room been overdriven easily, assuming that the driver is being operated at a level that overloads the room. In other words, a small bass driver is far less likely to overload a room than a large bass driver as similar power is applied to said driver. The large bass driver has more ability to move large quantities of air than the small bass driver ( a general statement, but assuming a proportionate size magnet, surround roll, choke, cabinet, etc). Plus, i think listening to the end result of set-up, trumps measurements every time. All IMHO.
Frantz,
IMHO the Welti/Dvantier aka Harman method and the Earl Geddes method can not be considered variants of each other. They aim at different objectives, use very different approaches and need different type of subwoofers. Nyal Melior summarizes them pretty well in his site http://www.acousticfrontiers.com/whats-new/2010/10/29/using-multiple-subwoofers-to-improve-bass-the-welti-devantie.html
I am happy that we agree it is not a simple thing.
And we should not forget the new JBL Synthesis multi sub system that Amir described in WBF and I consider most promising - but it is proprietary and needs specific Harman hardware. This system seems to avoid most of the listening phase - the optimization is almost automatic. If I had a serious home theater system I would surely get it!
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