u/loudifier

Looking to upgrade from a Prusa MK3 to something bigger. SV08 or maybe SV08 Max seem like a good option, but I am seeing people disagreeing about taco bed fix, references to Klipper mainline, alternate hotend compatibility, etc. Is there a wiki or forum with guides with consistent information that people are generally in agreement about?

Questions for this crowd:

- People seem happy with Max including all of the upgrades that SV08 should have, but underwhelmed by the print quality. Is Max just not sturdy enough for its size?

- Is taco bed actually fixed on currently shipping SV08? Aside from the fan, what other upgrades does it really need?

- What is the hotend/nozzle compatibility situation? I print mostly PLA/PETG, but occasionally abrasives or TPU. How hard is it to swap nozzles or open things up to clear jams/clogs?

- How is compatibility for upgrades in general? Can I generally assume that stuff designed for Voron 2.4 will work for SV08? Multi-material isn't a huge priority for me, but is there a multi-material option that most people agree on?

- I realize answers in this sub are probably a bit biased, but are there other large printers anyone would recommend? Not interested in Bambu's walled garden and Prusa XL is just way too expensive.

Edit: a lot of good feedback. Pretty sure I'm going to get a Voron kit instead. Thanks /r/sovol lol

Let me start by saying that if you just want to make speakers and you are having fun, then that is great and I am happy for you. I strongly encourage you to make speakers that are designed with aesthetics first, even if that results in suboptimal acoustic performance.

That said, there are tons of guides, free software, and affordable measurement microphones that make acoustic measurements approachable for hobbyist speaker builders and you should be measuring your speakers. If you spend any amount of time in WinISD or Hornresp or VituixCAD tweaking your design before you actually build it, you would benefit greatly from verifying that your speakers are built correctly. You can't fix directivity or distortion issues, but if you have a way to apply EQ you can improve frequency response or even extend your effective bass response. If you want to experiment with things like stuffing materials or adjustable port lengths, measuring the effects of your changes will be infinitely more accurate than listening tests.

This particular recommendation to measure your speakers was prompted by a post last week about a speaker design that was being presented as "optimised". The audio world is flooded with pseudoscience and some outright misinformation, so claims of optimization invites a certain level of scrutiny, and the comments on the post included some... light disagreement about the value of measurements. So let's measure that speaker.

The design includes STLs and a Bambu print profile, but I have a Prusa Mk3, so the settings don't come through in PrusaSlicer and the main speaker shell is larger than my print volume. I just went with the draft preset and 10% support cubic infill. The walls of the shell are really thick, so I was able to cut the top and bottom of the shell off without impacting the internal features and fit everything in the build volume. I also filled the hole for the speaker wire and shrunk the driver mounting holes to avoid needing heat set inserts. The shell and stand were printed in PLA. For anybody concerned about the differences in material and infill settings from the intended design, I have already done experiments that show negligible differences between wildly different materials.

https://preview.redd.it/fjei7lm7kq2h1.png?width=2188&format=png&auto=webp&s=de63b36bbf7bf7ec0404cdb4e6db84e4cd2e6c90

I started by measuring the raw speaker straight off the printer without the stand or any stuffing.

https://preview.redd.it/7r7603lwnq2h1.png?width=1904&format=png&auto=webp&s=bc50b4f8c91475f1a6060e5efc44768735342b62

The response will look familiar to anyone who has built and measured speakers using the PS95. Port tuning at 80Hz reinforcing the low end a little, resonant bump around F0, with a baffle step around 1kHz that flattens out to some ripples at high frequencies.

https://preview.redd.it/z0iq8h1qlq2h1.png?width=1456&format=png&auto=webp&s=d7e4f57b08cf818ce46c8fc016e16f76a7aa07d7

This speaker would go great in a 2.1 setup with some distance or off-axis orientation, just don't use them for near field monitors toed in to point directly at your ears, or they will sound overly bright. If you do want to use them on-axis they really need baffle step correction at minimum, but correction for the 80-300Hz region would also help a lot for low voice band.

"But you didn't even add the stuffing and stand!!1!" True. Let's add the stuffing that the original design calls for and put it on the intended stand.

https://preview.redd.it/uiqfd3e6oq2h1.png?width=1490&format=png&auto=webp&s=29c11bf9d1972d3c3de20014857013c65b17399d

I grabbed some random packing foam and stuffed it to a similar amount as what is visible in the original post, maybe a little less. The specific foam isn't specified, but what I have looks similar and if it is doing anything at all I would expect using the wrong foam would have a more dramatic impact (even if that impact is negative). I measured the speaker with just the foam added. I also printed dimples and glued them on to restore the fully spherical outer profile of the original design and put the sphere on its intended stand. The heavy speaker and light shell made the whole sphere really front heavy and there wasn't enough friction to keep the sphere from rotating downward, so I used little balls of blue tack to hold it in place. Then I measured that setup.

https://preview.redd.it/e1g8hhj0pq2h1.png?width=1904&format=png&auto=webp&s=eb11af576b7d40b027bbc831751f8023717ba529

And those changes make basically no difference, less than 1dB, which is probably due to measurement setup repeatability. As a point of reference, I also swapped in a different PS95 to show the magnitude of the design optimizations compared to the typical unit to unit variance of speaker drivers.

https://preview.redd.it/l0tssx82yq2h1.png?width=1456&format=png&auto=webp&s=bf4e266ab19c788e7684f52a975bc43f1fb690ca

For reference, let's compare this design to some other PS95 speakers. I have a couple of my own designs that I have shared, the Hilbert Reflex and a much smaller spherical speaker. I took the same PS95 driver and swapped it into each of the different designs to isolate any differences to the actual speaker cabinets as much as possible.

https://preview.redd.it/u5m837fitq2h1.png?width=1904&format=png&auto=webp&s=5c284673155ac20841fb026047ad568ba106f882

https://preview.redd.it/h6jsz0bktq2h1.png?width=1904&format=png&auto=webp&s=6b01cfb2ee50e79bfd930ca871e5e6ce80b94cf9

https://preview.redd.it/r6tm60r0uq2h1.png?width=1456&format=png&auto=webp&s=a9cd85d72e20fd2a4ae3080b23c58c4d96b82611

The large sphere and small Hilbert reflex have very similar tuning and remarkably similar responses. The Hilbert reflex has a nasty secondary port resonance that causes a null at 500Hz, but aside from that they are within the typical variation of a left/right pair of speakers off of an assembly line. The smaller sealed sphere is the outlier, showing more drop off below resonance, sharper and higher frequency F0 resonance due to the undersized back volume, and worse baffle step response.

In practice, all three designs sound remarkably similar. The PS95 just isn't very well suited for anything below 200Hz. Even in a ported configuration, the -10dB drop off from 160Hz to 80Hz doesn't go very far to reinforce the low end. In my opinion the PS95 has two desirable features - it is cheap and it looks very nice (which are entirely valid reasons to select it as a driver!)

I did notice one significant difference between the sealed and ported speakers. The PS95 has pretty limited excursion, and driving it below resonance produces noticeable distortion. The ported speakers have reduced excursion around the port frequency and more actual output, so they are much better behaved in that region. In my experience, below -20dB is a good target for low-order THD, and the small speakers are above that threshold below 100Hz. It is subtle for most stimulus, but could be audible with some vocal or piano content.

https://preview.redd.it/4d31lbgw1r2h1.png?width=1557&format=png&auto=webp&s=286343dbbaf6773a01dfdb1e379d021f975e9cb7

But so far we still haven't addressed the optimizations of the original design. It is unclear exactly what those optimizations are, but interpreting the original reddit thread and description on MakerWorld, it sounds like the goal was to make these speakers act as true point sources, using "point source" drivers and a spherical cabinet, and some sort of calculation in the design phase, possibly using path tracing simulation...

So I also measured the off-axis response of the original large sphere and Hilbert reflex to see how two very different cabinet shapes and port placements would impact the directivity. I didn't do a full spinorama, just spot-checked 30 and 60 degrees off-axis. Sorry, the full comparison plot it is a bit of an eye chart.

https://preview.redd.it/9h2cinwv4r2h1.png?width=1456&format=png&auto=webp&s=9025ee74e15c873fa764ae257e5ffa5cffd1845f

The big takeaway is that the directivity is dominated by the driver itself. The 30 degree responses deviate slightly above ~6kHz, but not enough that I would consider meaningful, and that might have been due to my placement being off by a few degrees. The low bass response diverges much more, which is likely a combination of measurement variability at low frequencies, different port placement, and slightly different port tuning/shape. At 20dB below the response at the port tuning frequency and 30dB below the response at F0, I wouldn't consider it a meaningful difference.

Aside from the Hilbert dip at 500Hz, these two wildly different speakers are functionally acoustically identical. I don't want to discount the work that went into the original design. I just want to push back a bit on the extreme lengths and work that people go to in pursuit of improved performance... that is actually just vibe-tuned by ear. Great sound is achieveable with some research and minimal investment, and I think there is value in doing experiments to figure out what actually makes a meaningful difference in your design.

Again, I want to reiterate that if you are happy going off of vibes, I am happy for you and fully supportive. More people in the DIY space is good, whether you want to take a scientific approach or not. If you want to optimize your designs, I strongly encourage you to try taking measurements of your speakers.