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LFR1100 ACTIVE - Configuration, wiring, and setup
#435794 02/24/20 05:37 PM
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Andrew Offline OP
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Hi Everyone,

The LFR1100 Active is a very special loudspeaker system, but it's also much more complex from a component and wiring standpoint than a typical setup. I thought a little "best practices" guide might be helpful. I’m also happy to answer any of your LFR1100 Active questions in this thread.

Components

The LFR1100 Actives come with a separate DSP chassis for each channel. When selecting partnering amplification, it's best to dedicate a single 5-channel amplifier (or a combination of amplifiers to make up five channels) to ONE speaker channel. That means one DSP to one amplifier. Combining connections from two DSPs to a single amplifier can sometimes result in signal ground loops that cause buzzing or hum. Ideally you would also not share the LFR amplifiers with other speaker channels in your system for the same reasons (like using a 6-channel amplifier for one LFR and your centre channel).

Wiring

If you’re taking advantage of the custom-made, color-coded wiring loom that we’ve made available for the LFR1100 Active, it might be confusing to come up with the correct interconnect lengths without having the components in front of you. If you’re stacking your amplifiers on top of the DSPs, you would want an interconnect length of 18 inches. Likewise, if you’re going to have your amplifiers and DSPs side-by-side on a shelf, you want an interconnect length of 36 inches, plus whatever spacing you think you’ll have between the components. As for which type of interconnects to use, we strongly suggest using balanced XLR connections if both your pre-amp/processor/receiver and your amplifier(s) have them available. You should never mix XLR and single-ended RCA connections on the DSPs as you’ll experience a gain mismatch. All interconnect cables should be kept as far away from AC cables as possible.

Placement

Omnidirectional loudspeakers like to have some breathing space behind them to perform their best, but it’s not necessary to have them many feet out into the room. Obviously, placement is going to be highly dependant on your actual room, but the DSPs allow you to tailor the amount of rearward information via the Boundary Compensation switch. This control is also very useful if you have an asymmetrical room layout, or a rear wall with openings like doorways, etc., as it will allow you to balance the sound between the left and right channels. For the electronic components, it’s best to have each chassis on a dedicated shelf with adequate air space above the amplifiers. If you need to stack components, it’s best to have the DSP under the amplifier for proper ventilation. Cables should be routed in such a way to keep low-level interconnects together and away from AC cables. It’s also a good idea to have all of your components on the same AC circuit as it will minimize the chance of ground loops.

Thanks and happy listening!

Andrew

Re: LFR1100 ACTIVE - Configuration, wiring, and setup
Andrew #435796 02/24/20 08:59 PM
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Originally Posted By Andrew
As for which type of interconnects to use, we strongly suggest using balanced XLR connections if both your pre-amp/processor/receiver and your amplifier(s) have them available. You should never mix XLR and single-ended RCA connections on the DSPs as you’ll experience a gain mismatch.

Thanks Andrew. Very useful.

I had been planning to use RCA from pre-amp to DSPs and XLR from DSPs to amps... how bad would this be ? I did have a vague nagging thought that XLR signal levels were traditionally higher than RCA levels but was thinking that just meant I shouldn't be using XLR-to-RCA cables anywhere.


M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8
Re: LFR1100 ACTIVE - Configuration, wiring, and setup
Andrew #435797 02/24/20 09:17 PM
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Thanks Andrew, great info! I do have a ADA1500 channel assignment question for you.

If I had an ADA1500-8, there are 4 amp boards in it and each board is limited to the power it can put out. So, If I were to connect an ADA1500 to one, and also want to power 1 surround (say a QS10HP), and a rear (say a QS8), what would be the optimal connection strategy? I was thinkin the following:

Board 1 - LFR1100 Front Bass, Second Slot Unused
Board 2 - LFR1100 Front Mid, LFR1100 Rear High
Board 3 - LFR1100 Front High, LFR1100 Rear Mid
Board 4 - QS10HP, QS8

Thoughts?


LFR1100 Actives,QS10HPx2,QS8x2,EP800,M3x4,M3x2 (Wood),M5HPx2 (Wood),AxiomAir,ADA1500-8,ADA1500-7
Re: LFR1100 ACTIVE - Configuration, wiring, and setup
bridgman #435799 02/24/20 09:49 PM
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Originally Posted By bridgman
Thanks Andrew. Very useful.

I had been planning to use RCA from pre-amp to DSPs and XLR from DSPs to amps... how bad would this be ? I did have a vague nagging thought that XLR signal levels were traditionally higher than RCA levels but was thinking that just meant I shouldn't be using XLR-to-RCA cables anywhere.


With RCA in to the DSP and XLR out you will be fine, you'll just have 6dB of additional gain which will likely result in the same output level from your amplifier as if you had used the RCA input (assuming your amp has a truly balanced input). The other way round (XLR in and RCA out) would result in a loss of 6dB of gain and you would probably clip the DSP before being able to drive your amp to full power. Our DSPs are unity gain so that 1 Vrms in equals 1 Vrms out RCA to RCA or XLR to XLR.

Thanks,

Andrew

Re: LFR1100 ACTIVE - Configuration, wiring, and setup
SRoode #435800 02/24/20 09:53 PM
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Andrew Offline OP
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Originally Posted By SRoode
Thanks Andrew, great info! I do have a ADA1500 channel assignment question for you.

If I had an ADA1500-8, there are 4 amp boards in it and each board is limited to the power it can put out. So, If I were to connect an ADA1500 to one, and also want to power 1 surround (say a QS10HP), and a rear (say a QS8), what would be the optimal connection strategy? I was thinkin the following:

Board 1 - LFR1100 Front Bass, Second Slot Unused
Board 2 - LFR1100 Front Mid, LFR1100 Rear High
Board 3 - LFR1100 Front High, LFR1100 Rear Mid
Board 4 - QS10HP, QS8

Thoughts?


Having the bass on it's own amp module is a good idea, but I would recommend having the front high and mid and the rear high and mid together on one amp board, don't mix front and rear. It's cleaner from a path back to the star ground in the DSP that way and will likely result in a slightly lower noise floor.

Thanks,

Andrew

Re: LFR1100 ACTIVE - Configuration, wiring, and setup
Andrew #435801 02/24/20 10:02 PM
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Super, thanks Andrew!


LFR1100 Actives,QS10HPx2,QS8x2,EP800,M3x4,M3x2 (Wood),M5HPx2 (Wood),AxiomAir,ADA1500-8,ADA1500-7
Re: LFR1100 ACTIVE - Configuration, wiring, and setup
Andrew #435803 02/24/20 11:25 PM
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Originally Posted By Andrew
With RCA in to the DSP and XLR out you will be fine, you'll just have 6dB of additional gain which will likely result in the same output level from your amplifier as if you had used the RCA input (assuming your amp has a truly balanced input).

Thanks Andrew. The amps are ADA1500's so I imagine they should be OK.

I will be mixing channels since I originally bought an ADA1500-4 for passive LFRs... the plan is to use that for the woofers and I ordered an ADA1500-8 for the mids & highs.

Sounds like I should keep mid/high for each of front/rear/left/right on the same amp board (guessing that's two adjacent outputs) ?

Even more useful information, thanks !!

Last edited by bridgman; 02/24/20 11:29 PM.

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8
Re: LFR1100 ACTIVE - Configuration, wiring, and setup
Andrew #435805 02/25/20 12:10 AM
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Hi Andrew, this is a pretty basic question. I’m sure I have missed it, but I’ve been trying to find the dimensions of the DSP unit. I will be stacking each with an ADA 1500 and I’m trying to decide on placement. What is the height dimension of the two stacked on top of one another? Thanks

Re: LFR1100 ACTIVE - Configuration, wiring, and setup
bridgman #435820 02/25/20 10:15 PM
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Andrew Offline OP
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Originally Posted By bridgman
Thanks Andrew. The amps are ADA1500's so I imagine they should be OK.

I will be mixing channels since I originally bought an ADA1500-4 for passive LFRs... the plan is to use that for the woofers and I ordered an ADA1500-8 for the mids & highs.

Sounds like I should keep mid/high for each of front/rear/left/right on the same amp board (guessing that's two adjacent outputs) ?

Even more useful information, thanks !!


Yes, with ADA1500s you will be fine. If you can avoid mixing channels from the left and right DSPs on the same amp module, that will be best. The two channels from one amp module go to each grouping of four binding posts.

Thanks,

Andrew

Re: LFR1100 ACTIVE - Configuration, wiring, and setup
korkster #435821 02/25/20 10:18 PM
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Andrew Offline OP
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Originally Posted By korkster
Hi Andrew, this is a pretty basic question. I’m sure I have missed it, but I’ve been trying to find the dimensions of the DSP unit. I will be stacking each with an ADA 1500 and I’m trying to decide on placement. What is the height dimension of the two stacked on top of one another? Thanks


The total height of an ADA amp stacked on top of a DSP is approximately 9 3/8", including the feet.

Thanks,

Andrew

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