ML Vista Crossover Bypass

---UPDATE---

The panel crossovers have been by-passed. I managed to not let the smoke out of the box . I haven't performed any measurements yet, but by changing the panel circuit resistor values, I think that I'm almost back where I started in regards to sound quality (to me, this is an achievement). Measurement and PEQ to follow. This is very cool. The highs sound beautiful. The bottom end needs attention. Woofer integration will be the big hurdle.

The new woofer enclosure is coming along nicely.

Enjoy your Evening!

Great stuff keep feeding us . You are lucky to have this ability

beek said:

Great stuff keep feeding us . You are lucky to have this ability

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Thank you for the encouragement, beek. I think the best way to learn how to swim, so to speak, is to jump right into the water. This project continues to be a great learning experience for me, one which will hopefully give me a good understanding of ESLs, Cones and DSP setup. Honestly, the most trying part for me, because I'm somewhat impatient, is going to be finishing the woofer enclosures. It's always the painting that brings on a tantrum .

For those who seek information, the panels are now wired in the following manner:

a) Negative cable from binding post to Black conductor on toroidal step-up transformer, and negative Music Sense terminal
b) Positive Cable from binding post to (2) 1 ohm/ 16 watt Solen AchrOhmic resistors, (in parallel 0.5 ohms) wired in series, to red conductor on toroidal step-up transformer, and positive Music Sense terminal.

- This setup produces sound in the normal way, with no overloading of the amplifier. However, in order to roughly dial in the panel output to the woofers' output, I have been adding resistors in series with the positive panel conductor. The current resistance value stands a 1.5 ohms, but I will be experimenting up to 3 ohms, and everything in between.

RUR, you were correct; the sound coming from the panel after the bypass is stunningly detailed. The entire setup obviously requires a lot of fine tuning, but I can certainly see the potential of this configuration.

Tosh, thank you for your expertise in determining the circuitry required to by-pass the crossover network for the panel, and your insight into the construction and configuration of the woofer enclosure.

Will update as new milestones are reached!

Wait 'till you get the woofers going, complete with a few intelligently applied PEQ filters via that DSP-enabled plate amp.:music:

Hi Guys, sorry I'm late to this party, but here are a few thoughts and I'll add specific responses as reply's to quoted posts.

First, congratulations Intermechanico, you are making great progress!

You've been well counseled so far, and it's great to see the support for yet another full-active conversion going on. As you are seeing from your early results, it's pretty magical compared to a passive setup.

One comment I'll make about crossovers and crossover points is that the panels, even really big ones like my monoliths, do not play both loud and deep. I made measurements on both the Monoliths and the SL3 panels and I found that the SL3 panel really would not handle much below 320Hz cleanly at 90dB, and the Monolith could only go to 260Hz before the distortion started rising. So my crossovers are now set at 256Hz with a fourth order slope (LR) for the HP on the Monoliths and at 400Hz first order (BS) slope for the SL3XC panel.
I had been running the Monoliths set higher (around 315Hz) which gave me good headroom in the crossover region, but I prefer to let the panel go a bit deeper in the mid-bass and just not crank it as hard.

For your Vista panel, I'd guess a good starting point would indeed be around the 350 to 400Hz range and use a steep slope in the miniDSP. One of the advantages an active brings is you can go with super steep xovers with very little penalty. I believe Sanders uses 48dB/octave LR in his active setups.

As for the woofer, my first reaction is to suggest you keep it simple and focused on giving you nice clean output between 50 - 60Hz and 500Hz and use two subs elsewhere in the room to give you balanced bass performance. As other have noted, the location where the panels perform their best is not likely = to the ideal low-end locations.
I did a test with four cheap subs that just blew me away at how good bass can be if you position the subs for smooth in-room response. Throw DSP on top of that, and you will not believe it yourself.
Anyway, my advice is look for a woofer driver that has excellent performance up to 800Hz or so, that will exclude pretty much anything labeled for 'sub' duties. You want a lightweight cone, low THD and no breakups until above 800Hz. This means it will likely only go down to 50 or so, maybe higher. That's fine, as you then feed everything below that to the subs.

Given that a woofer handling content well up to 500Hz should definitely be pointing in the same direction as the panel.

Don't sweat the woofer to panel physical alignment too much as you can tweak delays in the miniDSP. Just measure the impulse responses of each individually and adjust delay and phase as needed. Once you perfectly align the two impulses, more magic happens

InterMechanico said:

...

For those who seek information, the panels are now wired in the following manner:

a) Negative cable from binding post to Black conductor on toroidal step-up transformer, and negative Music Sense terminal
b) Positive Cable from binding post to (2) 1 ohm/ 16 watt Solen AchrOhmic resistors, (in parallel 0.5 ohms) wired in series, to red conductor on toroidal step-up transformer, and positive Music Sense terminal.

- This setup produces sound in the normal way, with no overloading of the amplifier. However, in order to roughly dial in the panel output to the woofers' output, I have been adding resistors in series with the positive panel conductor. The current resistance value stands a 1.5 ohms, but I will be experimenting up to 3 ohms, and everything in between.
...

Click to expand...

You can always adjust gain to the panel in the crossover block themselves. I do that in my setup, as there is something like a 6.6dB difference between panel woofers in my center channel, and 10dB difference for the Monoliths. In both cases, woofers are the ones with the gain.
Using resistance works, but does affect the load on the amp, possibly to good effect if the amp does not like low impedances, but possibly limiting the amount of effective volt-amps that can be delivered.

In my SL3XC, I used the three factory 3 ohm 20W resistors in parallel (1ohm 60w total) as an optional pad for the amp. Turns out Sunfires and Sanders amps are happy driving the raw transformer input with no further padding required. I modeled the effect of the padding in this post, so it does have an effect on the frequency response as well.

Do re-read my SL3XC build story, lots of good info in there for a project like yours.

Thank you for your help, JonFo. I'll have another look at your SL3XC write up. I have been quite busy at work these last few days, and so I have been unable to perform any further adjustments to the crossover settings or amplifier gain. I'll definitely try in the next few days.

Woofers have been ordered

I have placed the order for the (2) Seas L26R0Y04 and (2) Seas W22EX001 with Solen. Not sure when they'll arrive, but I better get moving on the enclosures.

InterMechanico said:

Seas L26R0Y04

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No can find this one, Julian. Do you have a link?

RUR said:

No can find this one, Julian. Do you have a link?

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Sure thing. Here you are:

https://www.madisoundspeakerstore.com/approx-10-subwoofers/seas-l26roy-10-subwoofer-d1001-04-4-ohm/

Inter, that driver you linked to is primarily designed for subs, and while it does a have a decent upper end, I'd worry that the moving mass of that thing (>100g) will have an impact on how clean a mid-bass one gets out of it.

I would have gone with something like this:
https://www.madisoundspeakerstore.c...ge-ca26rfx-h1305-10-coated-paper-cone-woofer/

With only 36g of mass, this one probably has much cleaner performance up past 500Hz. You do give up on the low end though, which would require a sub to be in the system.

JonFo said:

Inter, that driver you linked to is primarily designed for subs, and while it does a have a decent upper end, I'd worry that the moving mass of that thing (>100g) will have an impact on how clean a mid-bass one gets out of it.

I would have gone with something like this:
https://www.madisoundspeakerstore.c...ge-ca26rfx-h1305-10-coated-paper-cone-woofer/

With only 36g of mass, this one probably has much cleaner performance up past 500Hz. You do give up on the low end though, which would require a sub to be in the system.

Click to expand...

Not to worry! The L26ROY04 is only going to be employed to produce those frequencies up to 100 or 150hz in its own section of the enclosure, rear firing. For the range beginning at 100hz or 150hz up to 450 hz (or so), I will be using this: https://www.madisoundspeakerstore.com/approx-8-woofers/seas-excel-w22ex-001-e0022-8-magnesium-cone-woofer/ in what will be a fully active, tri-amped and DSP powered speaker. I like the sound of that

Crossover frenquencies

While I'm building the new woofer enclosures, I have re-assembled the Vistas so I can spend some time working out where the panel/woofer crossover point should be set, and what slope to use. I began, in a suitably inexperienced manner, by setting the crossover point at 350 HZ employing a Linkwitz-Riley 48db/octave slope with some overlap to be safe. Some of you know full well that that would sound like crap. For those that don't, it does sound like crap. I then settled into some light reading about setting up passive and active crossovers, and have since re-configured the crossover to 450 hz (stock) with a 12db/octave Bessel slope. The slopes intersect at -5db and it's sounding much better. I still have much work to do, and to re-do once the other enclosures are complete, but for now, it sounds quite good with everything thumping, bumping and singing just right. Vista Ultra Magnus Project is chugging along, folks.

Anyone have a link to a multi-angle panel cut calculator?

I would appreciate some advice on choosing an amplifier for the subwoofer section of the new enclosures. I'm not 100% decided on what the configuration should be. I have (2) MiniDSP PWRIce 250 plate amps which I'm using now to manage and power both the panel and the woofer section (250 watts per channel x2 ch. per amp). Now, should I, assuming a maximum budget of $2000.00:

a) order 2 more of the PWR-ICE 250 and run 1 per sub (630 watt bridged) and carry on

b) use the plate amps on the woofer and subwoofer (250 watt per driver) and find a suitable component P/A (the possibilities!) to power the panels and a MiniDSP 2x4 or something similar to perform the crossover and room EQ functions

c) use (1) PWR-DSP 2 MiniDSP plate amp (800 watt x2) with dsp and Ethernet connectivity

d) use (2) PWR-DSP 1 MiniDSP plate amp (2400 watts x1) with dsd and Ethernet connectivity (overkill? YES, Unlikely)

Thoughts?

Julian, don't you already have the 2ch x 250W ICE plate amps with DSP? 250W should be plenty of power for the ESL panel, and you've already got digital Xover and PEQ built in. Anything else is a complication.

You're using two woofs per speaker? What's their impedence? How low do you plan to drive them?

Yes, you're correct in that I have those 2 ch. Amps and you're also correct in regards to the 2 woofers per enclosure; hence the need for 2 more channels of amplification (3 per speaker). I'm leaning heavily toward 2 more of the same plate amps for simplicities' sake. The panel sound great with the class D amplification, so I have no concern there.

Julian, for the two woofers per enclosure, are they both running same frequency band, or will they be crossed over, one to the other, making each speaker a 3-way?

Good morning, Ken. Each woofer will run a different frequency band. The 10" sub will cover up to 100-150 hz, and the 8" woofer will cover from 100-150hz - 450hz. I found it difficult to decide on a single woofer that could comfortably span that frequency range, hence the massive complication to the design of the enclosure. So yes, each speaker will be a 3-way design. Both drivers have the same sensitivity at 88 db, but given the much higher mass of the 10" sub, I imagine having extra available power is not a terrible idea?

OK gotcha. I don't know of a 3-way plate amp (perfect solution) off the top of my head. Let me look around.

In re: the varying power requirements, I have no real expertise. In theory, it's all about sensitivity. If both drivers are 88dB, they *should* require the same power to achieve a given SPL. In practice, there may be other design factors to consider. Maybe Tosh can help us out?

Quick results...

Since you need two crossovers per speaker, a 3-way plate amp would be ideal, but..... MiniDSP's only 3-way is 1550W/400W/400W, which is way more power than you should need. digmoda makes one, but I read that the price is high, and I can't find any retailer.

You could use a miniDSP 2x4 with the proper plugin to handle Xover and PEQ DSP, connected to a suitable Crown amp or amps. Or, you can try to find a 3-way Crown or QSC which includes the necessary DSP.