Maybe something to consider. Maybe I am wrong.
Your box is heavily stuffed. What we are achieving with stuffing closed boxes? We get apparently bigger volume due to lovered speed of sound. As you wrote Q fell from 0.90 to 0.74, what is not small step. So, as box is apparently biger, first standing wave is lower.
Try to model the box which dimensions giving Q=0.74 without any stuffing and calculate standing wave resonance. Could be close to your measured resonance.
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@Zvu I have, and yes, it looks like it's at the top of the pile.
My only concern is the high Fs (95 Hz) and the rising distortion from 250 Hz upward shown in the datasheet. I know it's measured at 110 dB, but I’m not sure where distortion will start creeping in at lower levels.
I came across this set of measurements:
https://www.robsandiy.com/html/mid_bass/bms_5s117_8.html
Distortion appears to sit between 0.1–0.2% at 85 dB across the passband I’m interested in, which is great. The Fs there shows 100 Hz, slightly higher, but it's still a lot of money to commit to something that's unproven for my application. I'd love to see some polar measurements too.
What are your thoughts?
I did A-B the single speaker against one of my Genelecs and I didn't like it but then I was probabbly looking for problems.
My only concern is the high Fs (95 Hz) and the rising distortion from 250 Hz upward shown in the datasheet. I know it's measured at 110 dB, but I’m not sure where distortion will start creeping in at lower levels.
I came across this set of measurements:
https://www.robsandiy.com/html/mid_bass/bms_5s117_8.html
Distortion appears to sit between 0.1–0.2% at 85 dB across the passband I’m interested in, which is great. The Fs there shows 100 Hz, slightly higher, but it's still a lot of money to commit to something that's unproven for my application. I'd love to see some polar measurements too.
What are your thoughts?
I did A-B the single speaker against one of my Genelecs and I didn't like it but then I was probabbly looking for problems.
Callooh callay, data confirmation day!
I had to get to the bottom of the cube crisis. Or is it a driver crisis? Crisis of confidence? Either way, I ran some tests.
I measured the Faital Pro 5FE120 (Drivers A and B) and used a Peerless P830870 as a control and 3D-printed an adapter that let it fit in the same box (adorable). All three were measured in:
Turns out the oddity around 1kHz in the 5FE120 made the box resonance tough to spot. It was there all along, just buried in the chaos. What are the chances that the 5FE120 response throws a fit right on top of the resoannce? The P830870 makes it easier to see - the resonance shows up around 1.2kHz and is completely killed by damping.
As @danibosn rightly pointed out, the resonance shifts lower when the 5FE120 is in the box. My guess is the big magnet and general driver bulk change the physics.
I had to get to the bottom of the cube crisis. Or is it a driver crisis? Crisis of confidence? Either way, I ran some tests.
I measured the Faital Pro 5FE120 (Drivers A and B) and used a Peerless P830870 as a control and 3D-printed an adapter that let it fit in the same box (adorable). All three were measured in:
- Free Air
- Un-damped Box
- Damped Box (rockwool + melamine foam)
Turns out the oddity around 1kHz in the 5FE120 made the box resonance tough to spot. It was there all along, just buried in the chaos. What are the chances that the 5FE120 response throws a fit right on top of the resoannce? The P830870 makes it easier to see - the resonance shows up around 1.2kHz and is completely killed by damping.
As @danibosn rightly pointed out, the resonance shifts lower when the 5FE120 is in the box. My guess is the big magnet and general driver bulk change the physics.
- Faital Pro 5FE120
- Peerless P830870
Also...
I did a couple more distortion tests on the 5FE120 alone in the cube at 80cm.
One where the SPL peaks at 85dB and another at 95dB.
I did a couple more distortion tests on the 5FE120 alone in the cube at 80cm.
One where the SPL peaks at 85dB and another at 95dB.
Good for you in persevering and doing some more experiments.
Printing the holder for the Peerless driver was a great idea to help you see what was really going on.
From what I remember for distortion for the 5fe120 that looks right. I have a Clio pocket and it simply provides THD, 2nd and 3rd distortion measurements which is handy for a sanity check.
Printing the holder for the Peerless driver was a great idea to help you see what was really going on.
From what I remember for distortion for the 5fe120 that looks right. I have a Clio pocket and it simply provides THD, 2nd and 3rd distortion measurements which is handy for a sanity check.
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I purchased 5fe100 and 5FE120's to try out an idea approximately two and a half years ago, so quite some difference in build dates I imagine.
My cabinets are slightly larger than your cube, being an approx 8Litre reflex and my measurements were at a lower level than yours. So there is likely to be some differences. Your point about spikiness could be simply differences in chosen resolution. I usually try to aim for 12th octave smoothing.
My cabinets are slightly larger than your cube, being an approx 8Litre reflex and my measurements were at a lower level than yours. So there is likely to be some differences. Your point about spikiness could be simply differences in chosen resolution. I usually try to aim for 12th octave smoothing.
Measuring Sanity (and Distortion) at 20cm
I'm human. I'm weak. I can't control myself.
The 5FE120 is OK, but I'd always be left wondering what it could’ve been like with something better. The BMS 5S117 gets recommended all over the place but I haven’t seen anyone actually use them in a project. So... here we are.
I ran some measurements to keep myself grounded and promptly found something that ungrounded me further. Distortion at 80 cm is clearly better than the 5FE120, but is it 400% more expensive better? At 80 cm, probably not.
But then...
My room’s noise floor is too high to measure distortion accurately at 75 dB, which is my actual listening level. So I set levels for 75 dB and 85 dB at 80 cm, then moved the mic to 20 cm. The measurements were enormously better.
Which got me thinking:
Anyway, I now have the best of the best (on paper, anyway). What’s clear is that most - if not all - 5" drivers have some weirdness around 2 kHz, probably down to inherent geometry. I’m hoping to tame that in the crossover. Either way, it's nowhere near as offensive-looking as the 5FE120.
Anyway, I can get on and finish the final cube cabs now...
I'm human. I'm weak. I can't control myself.
The 5FE120 is OK, but I'd always be left wondering what it could’ve been like with something better. The BMS 5S117 gets recommended all over the place but I haven’t seen anyone actually use them in a project. So... here we are.
I ran some measurements to keep myself grounded and promptly found something that ungrounded me further. Distortion at 80 cm is clearly better than the 5FE120, but is it 400% more expensive better? At 80 cm, probably not.
But then...
My room’s noise floor is too high to measure distortion accurately at 75 dB, which is my actual listening level. So I set levels for 75 dB and 85 dB at 80 cm, then moved the mic to 20 cm. The measurements were enormously better.
Which got me thinking:
- Is the room the reason distortion looks worse than it is? Maybe.
- Would the 5FE120 have looked better using this method? Probably.
- Was all this fuss for nothing? Possibly.
Anyway, I now have the best of the best (on paper, anyway). What’s clear is that most - if not all - 5" drivers have some weirdness around 2 kHz, probably down to inherent geometry. I’m hoping to tame that in the crossover. Either way, it's nowhere near as offensive-looking as the 5FE120.
Anyway, I can get on and finish the final cube cabs now...
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Building a cab with Fibracolour feels like getting back with a troublesome ex - I know you have problems, but I’m sure I can fix them this time...
If you’re mixing Valchromat/Fibracolour with anything clean-looking, treat them separately:
Now you’ve got a dust-proof barrier. When the black dust returns (and it will), you can just wipe it off.
On a massive positive: CAD and 3D printing saved me so much time, effort, and rage on the baffle recess.
If you’re mixing Valchromat/Fibracolour with anything clean-looking, treat them separately:
- Sand everything to 120g
- Then the birch with 180g to get rid of the black
- Mask it off
- Apply liberal coats of finish
Now you’ve got a dust-proof barrier. When the black dust returns (and it will), you can just wipe it off.
On a massive positive: CAD and 3D printing saved me so much time, effort, and rage on the baffle recess.
A short meditation on 3D printing
I bought the A1 Mini to knock out templates, small jigs, and general bits & bobs. The plan was simple: if it was a tool, it didn’t matter, but if it was for show, I’d print, fill, sand, paint. The print was just a base layer, like digital MDF. That idea vanished fast.
A warning to anyone chasing perfection, whether through personality, ego, expectation, or stubbornness: do not get into 3D printing.
The problem? Infinite tweaking.
I blinked and suddenly I was 14 hours deep into a print that had to be perfect, with minimal post-processing. Tonight I realised how absurd that mindset is and how much it’s slowed this project.
There’s a bit in the Nick Broomfield Cobain doc where his aunt says Kurt refused to use a drum machine and instead recorded a suitcase being hit for a bass drum, just to keep it pure.
Why? What’s the point of clinging to internal metaphysical restrictions like that (even tho my life has been littered with identical instances)?
Basically, I’ve lost all perspective. Pretty sure I’m sabotaging myself to delay finishing the project.
Don't start 3D printing unless you’ve got a planet’s worth of self-control. It is ecstasy and agony.
I bought the A1 Mini to knock out templates, small jigs, and general bits & bobs. The plan was simple: if it was a tool, it didn’t matter, but if it was for show, I’d print, fill, sand, paint. The print was just a base layer, like digital MDF. That idea vanished fast.
A warning to anyone chasing perfection, whether through personality, ego, expectation, or stubbornness: do not get into 3D printing.
The problem? Infinite tweaking.
I blinked and suddenly I was 14 hours deep into a print that had to be perfect, with minimal post-processing. Tonight I realised how absurd that mindset is and how much it’s slowed this project.
- The A1 Mini couldn't hack it, so I had to upgrade to a P1S
- A heatwave in England paused prints for days due to temp issues
- My brain is now full of post-processing techniques and theories, distracting me from the finish line
There’s a bit in the Nick Broomfield Cobain doc where his aunt says Kurt refused to use a drum machine and instead recorded a suitcase being hit for a bass drum, just to keep it pure.
Why? What’s the point of clinging to internal metaphysical restrictions like that (even tho my life has been littered with identical instances)?
Basically, I’ve lost all perspective. Pretty sure I’m sabotaging myself to delay finishing the project.
Don't start 3D printing unless you’ve got a planet’s worth of self-control. It is ecstasy and agony.
As you point out 3D printing can be a tough thing to get right all of the time, and the differing materials available can mean that something that prints nicely with correct dimensions for a snug fit in PLA doesn't give quite the same fit with PETG. Consequently designs need iterations to fine tune them for good print results. I am on the same journey myself, and it can be frustrating. I imagine more so for you with a young family and fulltime job.
I probably spend about four hours looking at YouTube videos compared to thirty minutes of useable print output. I would like to ideally integrate a a tweeter horn into the 3D printed baffle design. Also I want to try a whole 3D printed cabinet, but I will have to learn how to split the cab into two or three assemblies with rigid supports to allow solid bonding when assembled, timescales to hopefully achieve this I haven't a clue?
Keep chipping away at this slowly you will get there, you have already demonstrated that you can do it by your earlier designs.
Good luck.
I probably spend about four hours looking at YouTube videos compared to thirty minutes of useable print output. I would like to ideally integrate a a tweeter horn into the 3D printed baffle design. Also I want to try a whole 3D printed cabinet, but I will have to learn how to split the cab into two or three assemblies with rigid supports to allow solid bonding when assembled, timescales to hopefully achieve this I haven't a clue?
Keep chipping away at this slowly you will get there, you have already demonstrated that you can do it by your earlier designs.
Good luck.
@raymondj Thanks man and good to hear I'm not the only one! It's a totally seperate discipline within itself, itsn't it? What printer do you have and what CAD do you use? I found Onshape the easiest to pic up but I have learned of its limitations quite quickly in respect to editing STLs etc. Still, it's cloud based so I can do it anywhere!
THE GRILLES
Amongst the chaos I’ve had one REAL win with the printing.
Normally, I make my grilles from 12mm MR MDF because I can staple into it and easily shape it - but that comes with two problems:
The idea (cooked up in bed) is simple:
A 6mm-high curved frame with a locking ring that press-fits and pinches the fabric in place. Once locked, I run a bead of superglue around the joint. I made a shim to tape a utility blade to set at the right height to cut along the middle of the bottom lip of the grille. Magnets in the grille align with magnets below the top layer of the birch ply baffle to hold it in place.
After some tinkering I got the grille height down to 5mm - which increased my serotonin x10.
Hopefully the pictures give you the idea. The only snag is that if the fabric cut isn’t clean, you get some bobbly threads to fish out or tidy up. I was properly chuffed with this. Had a POC on the printer by lunch, and a working prototype by bedtime. JOY³.
Printed in PLA+, and it’s holding up nicely.
Oh yeah, the cube cabs are done too.
Phew.
Amongst the chaos I’ve had one REAL win with the printing.
Normally, I make my grilles from 12mm MR MDF because I can staple into it and easily shape it - but that comes with two problems:
- 12mm would look ridiculous on a cabinet this small.
- It might impact the response - not drastically, but still bad practice, I think.
The idea (cooked up in bed) is simple:
A 6mm-high curved frame with a locking ring that press-fits and pinches the fabric in place. Once locked, I run a bead of superglue around the joint. I made a shim to tape a utility blade to set at the right height to cut along the middle of the bottom lip of the grille. Magnets in the grille align with magnets below the top layer of the birch ply baffle to hold it in place.
After some tinkering I got the grille height down to 5mm - which increased my serotonin x10.
Hopefully the pictures give you the idea. The only snag is that if the fabric cut isn’t clean, you get some bobbly threads to fish out or tidy up. I was properly chuffed with this. Had a POC on the printer by lunch, and a working prototype by bedtime. JOY³.
Printed in PLA+, and it’s holding up nicely.
Oh yeah, the cube cabs are done too.
Phew.
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Graham great to hear things are going in the right direction. Very professional looking smart grills and now the the cube cabs are complete as well. 🙂
To answer your questions, I am late to the whole 3D printing world, received my Prusa Core One Kit about a months ago now and I am battling at a slow pace to learn Fusion, the free version. I have managed 250mm x 180 front baffles for a SB Acoustics 5 inch PFC_8ohm and a 20mm Peerless neo horn tweeter, However I need to think how I am going to mechanically mount these to a MDF test cabinet. I am also in the process of making some parts for the Audiomatica Medusa turntable. See here
https://www.audiomatica.com/wp/?page_id=3024.
When I look at the Prusa slicer settings the permutations for each filament are endless, consequently I feel if the Slicer settings for a specific type don't work well, you can spend a lot of time experimenting, up to now I have only used PLA and PETG, in the future when I have some need for some new jigs and fixtures I will aim to try ABS/ASA etc. These things take time.
Also I have made some Tee slot blanks for my non standard table saw which will help no end with obtaining more precise cuts.
Lots to learn, which keeps me quiet. As to making front baffles with a built in tweeter horn shape I will have to do further studying to understand how to approach this in terms of Horn profiles, mouth dimensions, and sealing with respect to how they modify the frequency response. In reality could be beyond my understanding. I will try some basic profiles and measure to get a feel for things initially.
To answer your questions, I am late to the whole 3D printing world, received my Prusa Core One Kit about a months ago now and I am battling at a slow pace to learn Fusion, the free version. I have managed 250mm x 180 front baffles for a SB Acoustics 5 inch PFC_8ohm and a 20mm Peerless neo horn tweeter, However I need to think how I am going to mechanically mount these to a MDF test cabinet. I am also in the process of making some parts for the Audiomatica Medusa turntable. See here
https://www.audiomatica.com/wp/?page_id=3024.
When I look at the Prusa slicer settings the permutations for each filament are endless, consequently I feel if the Slicer settings for a specific type don't work well, you can spend a lot of time experimenting, up to now I have only used PLA and PETG, in the future when I have some need for some new jigs and fixtures I will aim to try ABS/ASA etc. These things take time.
Also I have made some Tee slot blanks for my non standard table saw which will help no end with obtaining more precise cuts.
Lots to learn, which keeps me quiet. As to making front baffles with a built in tweeter horn shape I will have to do further studying to understand how to approach this in terms of Horn profiles, mouth dimensions, and sealing with respect to how they modify the frequency response. In reality could be beyond my understanding. I will try some basic profiles and measure to get a feel for things initially.
is this demand avoidance ? was the new printer loads better ? I don't want to get one and then outgrow it in 5 minutes ? the grilles look brilliant by the way I'd love to be able to make something like that . I would really like a 3d printer I just worry I'm not going to get the hang of the software .