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TOPIC: minidsp shd and subwoofer with highlevel connectio

minidsp shd and subwoofer with highlevel connectio 7 months 1 week ago #46708

Hi) I plan to purchase the Minidsp SHD but have a REL powered subwoofer that needs high level input conection from the mains of my amp. So the question is whether I may leverage minidsp shd to set crossover freq and use channel 3 RCA out to sub and ch 1 & 2 xlr to amp ? ..will this work out despite high level conection on my amp? how shall I do dirac ?please advise
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minidsp shd and subwoofer with highlevel connectio 7 months 1 week ago #46709

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gonzaloechavarria wrote:
Hi) I plan to purchase the Minidsp SHD but have a REL powered subwoofer that needs high level input conection from the mains of my amp. So the question is whether I may leverage minidsp shd to set crossover freq and use channel 3 RCA out to sub and ch 1 & 2 xlr to amp ? ..will this work out despite high level conection on my amp? how shall I do dirac ?please advise

If your subwoofer really doesn't have low level inputs I would forget using more than 2 channels. Connect it from your main amp and set its level and frequency range by ear, then let Dirac sort things out. My subwoofer does have low level inputs so I do use more than 2 channels but still don't bother with crossovers in the SHD, I route exactly the same full range signals to mains and sub.

High level means higher voltage signals suitable for driving passive speakers, the SHD line level outputs will not produce enough voltage to drive sub high level inputs properly but may just about work if your sub has enough gain.
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minidsp shd and subwoofer with highlevel connectio 7 months 1 week ago #46710

thanks for the help !!
yes my sub has low level inputs..so I guess the connection should be shd channels 1 & 2 xlr to amp and then channel 3 rca to sub low level inputs.... now...what should I do with the sub crossover knob and low level filter?
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minidsp shd and subwoofer with highlevel connectio 7 months 1 week ago #46712

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Yes, SHD 1 and 2 to mains amplifier, then 3 (or 3 and 4 if you have 2 low level inputs) to sub inputs. The Routing page in the SHD plugin application allows you to do whatever routing to 1, 2, 3 and 4 that suits you. My sub has two inputs so I route 3 and 4 to it. So Dirac Left goes to 1 and 3, Dirac Right to 2 and 4 for me. One way or another ensure you route both left and right to the sub.

As for crossovers and sub filter, there are several options depending on the relative merits of your mains and sub.
My mains are very good full range so I don't cross them over, if your mains or your mains amplifier are a bit less capable you may wish to cross them over with the sub to let the sub handle all the low end.

If you are crossing over the mains and sub in the SHD plugin set your sub cutoff as high as possible or disable the filter.

I personally take the view that crossovers are necessary when you don't have something like Dirac. When you do have Dirac there may be good reasons to use crossovers but they may not be necessary. Others disagree.
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minidsp shd and subwoofer with highlevel connectio 7 months 1 week ago #46715

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I would only use a single low level cable even if the sub has two inputs. The sub will sum the signal from the two inputs so you may as well do this with signal routing in the plugin and save money by using a mono rather than stereo cable. This is how I do it.

So if your single sub output is channel 4 you have input 1 routed to outputs 1 and 4, and input 2 to outputs 2 and 4.
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minidsp shd and subwoofer with highlevel connectio 7 months 1 week ago #46716

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What are the speakers and sub being used? This will affect how useful applying a crossover in the SHD is.
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minidsp shd and subwoofer with highlevel connectio 7 months 1 week ago #46718

Hola
The sub is REL T9 connected via High level input to a Hegel Rost amp that drives Kudos cardeas 10 ..see below the specs:

2-way Bass reflex standmount
Mid/bass driver 180mm unit
Frequency range
40Hz – 30kHz AIRR (average in-room response)
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minidsp shd and subwoofer with highlevel connectio 7 months 1 week ago #46737

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gonzaloechavarria wrote:
Hola
The sub is REL T9 connected via High level input to a Hegel Rost amp that drives Kudos cardeas 10 ..see below the specs:

2-way Bass reflex standmount
Mid/bass driver 180mm unit
Frequency range
40Hz – 30kHz AIRR (average in-room response)

I think it is worth you experimenting with different options to see which works best for you. One option is to simply try to blend the sub in to cover the region from below where the speaker output rolls off. Another would be to run a higher crossover (something like 100 Hz), applying a high-pass filter to the main speakers and a low pass filter to the sub at this frequency. This approach means your main speakers and amp are doing less work (which can reduce distortion) and allows a sub that has been placed optimally for bass performance to handle more of what it's better placed to do. I know @Entripy doesn't think these benefits are worth other trade-offs but I think it's worth trying to see what you think.

Either approach will rely on you getting good time and phase matching in the crossover region prior to running Dirac.
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minidsp shd and subwoofer with highlevel connectio 7 months 1 week ago #46738

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It all depends on the relative merits of mains and subs whether crossovers are worthwhile. In my case my mains are rather better than my sub so I'm not interested in "bass management". Rather the sub can be placed in a corner where it can fill in a 5dB suckout caused by SBIR of the mains (left only).

For gonzaloechavarria, he has very good mains and sub so its hard to know which way will work best but I would suspect crossovers may have merit. His sub usefully goes lower than his mains, mine doesn't, I picked one with an especially high rolloff (34Hz) to avoid a 29Hz room mode after finding a better sub just didn't suit this room. Worse sub, better overall sound. Its all about knowing your room and understanding its problems, knowing your mains and sub and understanding their merits. There is no one right answer that suits every situation. Dirac is good but optimising your speaker and sub positions and even treating your room is all worthwhile and appears to pay off even more in combination with Dirac.

But its also probably wise not to overthink things to begin with. Use REW to equalise the mains delays with the sub. Then maybe just start simple without crossovers and see how it sounds. Then consider and implement crossovers and see how that sounds. No amount of theory will be worth the results of experimentation. Calibration is simple and fast once you are used to it so it isn't like you need to get it perfect first time. Think of it as more of a process with the first attempt as practice.
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minidsp shd and subwoofer with highlevel connectio 7 months 1 week ago #46739

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For me I think the effects of the room and speaker placement are frequently such that even speakers that are 'good' for bass may still actually benefit from having more of this output taken over by a competent sub. I don't consider my speakers to be inherently poor in the bass department (review with measurements below) but I do still find a relatively high crossover to my sub beneficial (in combination with EQ).

www.stereophile.com/floorloudspeakers/669/index.html

My point being I would experiment rather than ever attempting to pre-judge this.
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