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SCH-REMOTE Digital VU/Spectrum Meter Review

Rate this VU/Spectrum Meter

  • 1. Poor (headless panther)

    Votes: 3 2.2%
  • 2. Not terrible (postman panther)

    Votes: 6 4.3%
  • 3. Fine (happy panther)

    Votes: 66 47.5%
  • 4. Great (golfing panther)

    Votes: 64 46.0%

  • Total voters
    139

Neddy

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There was an 8x8 channel 'stack of bargraph led strips' thing on ? kickstarter a while back I think.
Would have made a fascinating 8 ch VU meter (if horribly obnoxious) with some software/IO mods (IRCC, it was set up to be driven by a mic?).
It was on my list for a while to figure out how to attack...then covid and stroke hit, so dropped in to the 'not realistic' bin (I have too many of those projects still kicking around, like OLED lighting panels, and sound/motion sensitive LED underlit handrails, etc etc).
But sure looked tempting.
Not as cool as old timey VU meters, but.....jeepers with all those brainiac utubers (e-potatoes?) out there you'd think ONE of them would have cobbled that together by now.
:facepalm::eek:o_O:)
Edit: As an 8 ch spectrograph (granted, only @ 8 freqs) it'd be way cool.
Found it!
 
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Gruesome

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This is a review and measurements of the Sch-remote EVOR04-slim LCD based audio VU/Spectrum/Visualization module. It was sent to me by the company and costs US $78 ($72 in volume).
View attachment 280589
This is a two-board sandwich with the display in the front as you see. On the right there is a USB jack for power or a standard barrel connector for the same. Two analog stereo 3.5mm jacks are provided which you can select from the menu. Screen is touch sensitive. I think it is resistive though as it requires some pressure and has a delay before it detects your touch. To the extent you don't need to touch it often, it is fine.

The unit is hugely configurable through the menu system allowing you to set such things as sensitivity, etc. Here is a shot of the back where the guts are:
View attachment 280590

The display in person looks very good. There is a bit of dancing/sequencing pixel going on at times which I suspect is due to refresh rate. There are not only stereo and mono graphs but also differential (X-Y) displays as well. I like the simulated VU meter of which there are 4 or 5:

View attachment 280591

This one has peak detection. Here is a shot of it with my mobile phone:
View attachment 280592

Company also sent me a compact black plastic case for the unit to make it freestanding.

EVORO4-Slim Measurements
All the VU meters we have tested in the back have had poor front-ends, loading the input down causing severe distortion. So that was the first test I went for by first measuring my Audio Precision analyzer by itself:

View attachment 280593

I set the output voltage to 250 millivolts as by default the VU meter is setup for 20 dB gain. I then plugged the EVOR04 in parallel to the signal connection above:

View attachment 280594
As you see the impact is basically non-existent indicating a nice buffer in the front-end of the meter.

Not that it matters a ton but I wanted to see how flat the frequency response of the meter was. I used its own display to show the dB value while I selected four different frequencies (calibrated to 1 KHz):
View attachment 280595

As you see, there is a bit of drooping at both ends of the spectrum, dropping by 1 dB at 20 Hz and 1.4 dB at 20 kHz.

Last bit was frequency resolution when using the spectrum analyzer:
View attachment 280596

The meter was fed a pure sine wave at 100 Hz which should just create a vertical bar. It does that at higher frequencies but as you go down, it widens as you see. It would have been nicer to make this much narrower. Unfortunately that sharply increases the computational requirement (and slows down the response some). Not sure if there are spare CPU cycles to throw at it.

Finally, I connected the meter to my DAC and enjoyed beautiful dancing bar graphs with low latency:
View attachment 280597

What I wished the device had was IR remote. Then you could cycle through the visualizations in non-desktop applications.

Conclusions
I got into hi-fi in 1970s when VU meters and spectrum analyzers were often sign of status of the audio device. The larger the VU meter, the more high-end the unit was! Our sources were spinning devices whether we were talking cassette tapes, LP or reel to reel. Today, we have lost all of that with digital. Yes, software visualizations exist but they are too far removed from where the audio samples come out so they don't seem very connected to the music. And at any rate, they are not where they should be -- in our audio rack. I really like to see audio companies innovate in this domain and bring back attractive front panels sporting informative and beautiful displays. Modules like EVOR04 enable this as they seem to be built for OEMs to include in their audio devices.

I was pleasantly surprised how capable and flexible this meter is. I did not remotely do justice to its level of programmability in this write up. It does everything you wish and then some. I mean it even has two stereo audio inputs! And two ways of powering it.

On technical performance, there is no impact on your audio fidelity which is as it should be. The accuracy of the meter itself is not perfect but certainly good enough for fun.

I would like to see a more premium version of it with a stepped up display quality, remote control and better frequency resolution. As it is, what we have is quite compelling.

I am going to put the Sch-remote EVOR04 on my recommended list.

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As always, questions, comments, recommendations, etc. are welcome.

Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
Correction to my update on shipping: Svilen seems to be shipping out of Bar Harbor, ME now, even though the order web page still lists [Bar Harbor is probably just a USPS placeholder for the origin address] within a day from Romania to Louisville, KY, when selecting the Bulgarian and German postal service as providers for the cheapest shipping service (which is what I selected). I ordered and received the PayPal invoice on 4/22, shipping happened on the 24th (Monday), and on 4/26 USPS notifies me the unit is already in California.

And since this is my first post: Many thanks, Amir, for this awesome retirement project of yours!
 
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Madjalapeno

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I went with one of these for my diy streamer build - https://www.audiosciencereview.com/forum/index.php?threads/my-diy-streamer.28533/ - very happy with it.

Using it purely for visuals.

index.php
 

Gruesome

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Correction to my update on shipping: Svilen seems to be shipping out of Bar Harbor, ME now, even though the order web page still lists [Bar Harbor is probably just a USPS placeholder for the origin address] within a day from Romania to Louisville, KY, when selecting the Bulgarian and German postal service as providers for the cheapest shipping service (which is what I selected). I ordered and received the PayPal invoice on 4/22, shipping happened on the 24th (Monday), and on 4/26 USPS notifies me the unit is already in California.

And since this is my first post: Many thanks, Amir, for this awesome retirement project of yours!
Update II: the gizmo arrived on 4/28, six days after the order, and four days after it was shipped from Europe. I had to order an adapter to attach it to my headphone amp, so I could only try it out today. It's really neat; the 3D printed case fits well and snaps together safely, the predefined displays are easy to scroll through. Amir had already posted limits on the frequency response (about 1dB dropoff at 20Hz and 20kHz), so I thought as a first application (besides marveling at colorful spectrum analyzer displays and - supposedly - Revox-style VU meters) I'd try to measure the frequency response of my headphone amplifier at the headphone output, with and without headphones attached. I'll post that attempt in the Xduoo TA-10(R) thread.

Judging from swapping left and right channels, for my copy of the Evor04-slim, unchanged from factory settings, the difference between the left and right channel is 0.2 to 0.3dB, so around 6%, which doesn't seem bad.
 
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Gruesome

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The Revox style VU meter is from an A700. Only saw one once in the wild, so didn't recognize it initially.

OT: Just hypothetically, what would one use such a machine for if one stumbled across one these days? Mount small fans to NAB adapters, to cool your tube amp?
They seem to pop up on ebay once in a while...
 
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Gruesome

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The soldering/gluing job on the input connectors could be a bit sturdier. Connector 1 on my sample broke off already (right channel only working most of the time), so I now switched to the other input connector/channel. It might be a good idea to add some glue to these connectors first thing when you receive your unit.
 

GeorgeWalk

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I ordered one. I had to resolder the input connectors onto the board. They weren't securely soldered leading to noisy and intermittent operation.

I like the unit so far.
 

Gruesome

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I resoldered mine as well, and both inputs are working again. I also built the (~10:1) voltage divider, bought (and took apart and resoldered, one channel was noisy, which is somewhat ironic for a noise isolation gizmo....) a stereo noise isolation transformer and hooked the Evor04 up to the output of my Loxjie A30 amplifier. It works! The left channel of the Evor04 seems to lead the right one by 1dB, on both inputs. Now I need to do a better job shrink tubing the voltage divider. Right now it's just sticking out from the speaker clamps of the A30, like a piece of tube amp art....
 
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