Changed some colour settings. I am going to try to add to this if you don't mind
Currently working on enclosure. Trailed 6 mm marine ply for veneer and cabinet extension. Looks good, but I know it can look better, so now cutting up some birch timber dress panels. I see bass as a golden glow impression and silvery bits look too harsh and bright with bass, so this is getting the golden touch. I'll apply some sanding sealer to the dress panels and then go look for some Feast Watson tint vial for golden pine colour stain. I already picked up some choccy leather look upholstery fabric for the other surfaces. I need to find some golden sheen old tube cabinet radio type fabric for the grill work. I only have the master volume pot in the circuit at the moment, but will fit 3 more doin nuttin at the moment pots for upcoming master section tone controls. I only have some brushed aluminium hi-fi style knobs on hand, but will change to golden bass guitar type knobs after ordering some. The pots I have are the little green ones for PCB mount, but I will attach them with twisted cat5 core wires
Am fitting in the satellites at the moment, but won't hook them up until filters are sorted. Only a single mono preamp and volume getting activated for now
These are the largest full ranges that I have on hand. They make the new cab size quite large so will save them for future external speaker role. Will use these LG full ranges instead
These little ones seem quite capable and makes for a cab size that is easy on the eyes
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Trying to understand this, hope you guys do not mind educating
Is this a 1.59hz high pass filter to block DC at the input?
Can the values be changed to 10uf and 510 ohms or so to set a 30hz high pass instead?
Would this still block the DC?
Is it a bad idea to implement this sub sonic filter here?
If there is another stage in front of this circuit, e.g a summing stage, is that input DC filter (if that's what it is) still needed?
I hope these questions make sense as I don't even know if I am way off in understanding
Thanks and regards
Randy
Not in the slightest! 😀 That's why I posted my .asc file, so you could download it and mess with it, to give you a starting point.
-Gnobuddy
Yes and no...the capacitor is there simply, as you said, to block DC at the input so it doesn't mess with the op-amp. The 1.6 Hz frequency was chosen simply to be so low that it has no audible effect.
But the op-amp isn't there to be a high-pass filter; it's there to provide a very high input impedance to whatever plugs in to the input (left side of the circuit), and even more importantly, to provide a very low output impedance to the active filters that follow. Without that, the filters to the right of the input stage will not work as designed. You will not get the frequency response you expect.
That's an excellent question!
You could certainly raise the corner frequency to 30 Hz to help protect the sub. And yes, that would still block DC (though 10uF means an electrolytic cap, and they are "leaky" - a little bit of DC current does tend to leak through them.)
But that opens a whole can of worms. Let's talk about a few of them:
1) If you use 10uF/510 ohms, that would reduce the input impedance of the whole circuit to 510 ohms, which is very low indeed.
You could fix the ultra-low input impedance by using 100nF and 51k, or 10 nF and 510k, or 4.7 nF and 1.2 Meg. (Bigger resistors do create more noise...another issue.)
But...even if you used a relatively big R and relatively small C to get your nominal 30 Hz corner frequency, there are still more worms in the can to consider!
2) Worm: the output impedance of whatever is driving this circuit will mess up the 30 Hz corner frequency. This means you might have your desired 30 Hz cutoff frequency when you drive the sub from a bass guitar pedal - but it might drop to 1 Hz if you plug a passive bass guitar straight into the input! Depending on the R value you pick (510 ohms, 5.1k, 51k, etc), the cutoff frequency could be anywhere between 1 Hz and 30 Hz, depending on what is connected to the input. Not good.
4) Worm: this is only a first-order filter. In other words, even when everything is working ideally, it won't offer a lot of protection to your subwoofer, because frequencies below 30 Hz will still "leak through" quite a bit.
In my opinion, yes, for all the reasons raised above.
Because all these active filter topologies are sensitive to the source impedance from which they're fed, without that input stage, you'll have a low-pass filter you can't trust (cutoff freq varies depending on what you plug in.) And you can't trust the 30 Hz Hi-pass, either.
That is another excellent question. 🙂
The input stage's job really is to provide a high input impedance to the signal source, and a low output impedance to drive subsequent active filters. That prevents "tone suck" from the source, and allows the subsequent active filters to actually work as designed.
And the answer to your question is: if there is another stage in front, and that stage provides a rock-solid low output impedance, then no, you don't need this buffer stage.
On the contrary, I think you are asking very good questions, which means you are thinking along the right lines. Now all you have to do is give it another ten or twenty years of thought, and you'll be there. 😀
-Gnobuddy
Slow few days with the build. Mostly sitting and looking at it. Been working on the cosmetics and finishing off the enclosure. I have been lining the inside of the head section with al foil. I'll ground panel to panel with screw down contact tabs (braid shielding from audio wire with screws in each end). I'll attach that cabinet shielding to the system's electronic ground
Found another Logitech Z623 at the reuse centre today! This time complete with the satellites/control pod!! Again $10. Now I can have one for the test bench 🙂
On the finishing stage of the bass amp/PA combo enclosure now. Upholstery work completed. Working on the varnish for the dress panels now
On the finishing stage of the bass amp/PA combo enclosure now. Upholstery work completed. Working on the varnish for the dress panels now
I wish we had something like that. We have government-run recycling centres, where you can drop off electronics that will presumably be taken apart and recycled. But you are not allowed to buy or take perfectly functional electronics items that other people have already dropped off there. They all have to be destroyed.
There are thrift stores where you can buy items other people have gifted for free. Better than nothing, but a lot of stuff that goes to the recycling centre because its old or unfashionable, could still be useful for several more years. Like 2010 era PCs that would still run perfectly well, if you wiped the drive of Microsoft garbage, and slapped Linux on instead.
I'm typing this on 2011 PC hardware running Linux. Found on a loading dock with other trash, upgraded with a few sticks of old RAM, and a few-year-old SSD. It's fast and powerful for everything I do.
-Gnobuddy
Today I hope to have the enclosure completed. The look that I am going for is what I think is classic ambience, but if the designer would have continued his career through to current times
This is the project sub upholstered and next to it is the new one from yesterday. The material is a leather look upholstery fabric that doesn’t photograph well but looks gorgeous in person
Our reuse centre is town council run. Just about everything makes it’s way there and is very popular. Amazing for building materials and project parts. Our town is sometimes referred to as “the gods waiting room “. A lot of push bikes get transformed into tris that the seniors love hooning around our kilometres of waterfront pathways. We also have a kilometre long pier that is loved by the fisherfolk of both sexes. Fishing carts are also very popular. Always great to see the contraptions people come up with 🙂
Yesterday, while browsing the audio shelves, an elderly chap came up and asked for help to find something with which to enjoy some music in his workshop/ relax type area. Showed him a large sub from an obscure brand 5.1 system. It had all the built in amps, real wood veneer, actual knobs for the channel level controls, three sets of stereo inputs with matching individual select buttons as well as discrete 5.1 inputs with a selection knob. No remote control enabled
I showed him some AWA made in Taiwan large book shelf speakers. They looked like a classic 8” two ways and built quite solid. I thot that the combination of time period and speaker size would mean good efficiency and overall sound
I asked him if he had a smartphone, he had iPhone 6, brilliant start. Showed him how to find his songs on YouTube and showed him the right type of cable in the crates. Asked him to find more of the same for testing
I showed him how it all connects together. He took it up to the sales counter for testing and came back grinning like a kid. Then he asked if I could help him a bit more. He was looking for the ability to play cds and fm radio. With remotes for most things missing we came up with this that had most controls for cd and radio as well as usb. The speakers were missing but the central section looked pretty good.
http://en.all-specs.net/model/307423/
Also showed him how to id similar units and the different options around and how to read labels and impedance match
He found some speakers and took those for another test. Again came back grinning, the Panasonic worked perfectly. Then I showed him how to hook up his new sub/speakers to the headphone output on the Panasonic and he was openly getting emotional from the sound he was hearing
All speakers there are currently $2 each including subs. This ended up costing him $10 for the sub and two sets of speakers. The Panasonic was $5. He came back and said he had a very interesting day and learned a lot. He said that he felt he owed me and offered $50 and I declined. He insisted on shouting a case of beer. I told him to call me if he had any trouble
This is the project sub upholstered and next to it is the new one from yesterday. The material is a leather look upholstery fabric that doesn’t photograph well but looks gorgeous in person
Our reuse centre is town council run. Just about everything makes it’s way there and is very popular. Amazing for building materials and project parts. Our town is sometimes referred to as “the gods waiting room “. A lot of push bikes get transformed into tris that the seniors love hooning around our kilometres of waterfront pathways. We also have a kilometre long pier that is loved by the fisherfolk of both sexes. Fishing carts are also very popular. Always great to see the contraptions people come up with 🙂
Yesterday, while browsing the audio shelves, an elderly chap came up and asked for help to find something with which to enjoy some music in his workshop/ relax type area. Showed him a large sub from an obscure brand 5.1 system. It had all the built in amps, real wood veneer, actual knobs for the channel level controls, three sets of stereo inputs with matching individual select buttons as well as discrete 5.1 inputs with a selection knob. No remote control enabled
I showed him some AWA made in Taiwan large book shelf speakers. They looked like a classic 8” two ways and built quite solid. I thot that the combination of time period and speaker size would mean good efficiency and overall sound
I asked him if he had a smartphone, he had iPhone 6, brilliant start. Showed him how to find his songs on YouTube and showed him the right type of cable in the crates. Asked him to find more of the same for testing
I showed him how it all connects together. He took it up to the sales counter for testing and came back grinning like a kid. Then he asked if I could help him a bit more. He was looking for the ability to play cds and fm radio. With remotes for most things missing we came up with this that had most controls for cd and radio as well as usb. The speakers were missing but the central section looked pretty good.
http://en.all-specs.net/model/307423/
Also showed him how to id similar units and the different options around and how to read labels and impedance match
He found some speakers and took those for another test. Again came back grinning, the Panasonic worked perfectly. Then I showed him how to hook up his new sub/speakers to the headphone output on the Panasonic and he was openly getting emotional from the sound he was hearing
All speakers there are currently $2 each including subs. This ended up costing him $10 for the sub and two sets of speakers. The Panasonic was $5. He came back and said he had a very interesting day and learned a lot. He said that he felt he owed me and offered $50 and I declined. He insisted on shouting a case of beer. I told him to call me if he had any trouble
Gremlins!
Not happy with the wood colour tone, developed too dark, earmarked for some wet sanding to a lighter tone at another time
Had the whole thing assembled yesterday but no sound! Some frantic trouble shooting including AB testing with the other two working units and none worked. Turns out I made an error while decoding the D15 connector and labelled incorrectly. She is singing again now all taken apart, hope that continues once put back together again
Not happy with the wood colour tone, developed too dark, earmarked for some wet sanding to a lighter tone at another time
Had the whole thing assembled yesterday but no sound! Some frantic trouble shooting including AB testing with the other two working units and none worked. Turns out I made an error while decoding the D15 connector and labelled incorrectly. She is singing again now all taken apart, hope that continues once put back together again
Good of you to help!
Such a basic human thing to do, to help, and yet, so many won't do it. Ah, well.
I've got by with "universal remotes" for DVD players bought from the local thrift store that did not have their own remote control. If the brand name is reasonably popular, you can usually find a universal remote that will at least operate the basic and most necessary functions.
Wow. Those are awesome prices, especially when you compare with literally hundreds of dollars for similar new items.
You helped make someone happy, and helped keep some trash out of our dying planet. Win, win. Good for you!
I recently got a 42" TV for the spare room, for only fifty bucks off Craigslist. It's "only" 42" and 720p - and hardly anyone will touch those with a ten-foot pole these days, as people have been brainwashed to believe they need an enormous screen, 4k resolution, and a "smart TV" that spies on them constantly.
The silver lining to rampant consumerism is that, in the frantic race to spend as much as possible on the newest and shiniest and most fashionable things, there are lots of excellent low-hanging fruit left behind for those who take a more pragmatic approach.
-Gnobuddy
I advocate reuse and repurpose. Some of the contraptions here using bicycle frames are amazing. My daughter and I got an all terrain pram from there and turned it into a cart for the slopes here. Then we turned it into a barrow/carriage for hedge pruning
We are about to leave for a week’s holiday, driving to Sydney about 1400km away to see my folks. With the interstate move and then the virus border closures, it been three years
I picked up some smaller Logitech 2.1 systems hoping to make a lil boom box with it for holiday music. I think it draws less then 500ma at 250v so been wondering about the possibility to trace its DC input and see if can be powered with a power bank via a dc-dc converter. I also have a couple of double brick size sealed deep cycle batteries and a really good charger for them as well as alternator charging while travelling. My Subaru XV is well equipped with a comprehensive JL Audio system. Although I cooked my front C3 woofers in the splits and running backup drivers there. I need to get the C3’s repaired or look into some pro grade drivers from PRV or DSI. I need strong 400hz to 80hz in the front stage and one of my fav songs is a woofer killer at pleasing volumes. Running too high a low pass filter on the fronts to protect the woofers kills the song. Most other songs in my playlist are similar
Touching on the reuse centre again, our Subaru XV is a bit short on luggage space . Found this at the centre, older tan model in perfect condition with a pair of aluminium cross beams. Keys for roof rack beams and pod included with spares!
https://www.rhinorack.com/en-au/pro...boxes/masterfit-roof-box-370l-black-_rmft370a
All that for $10!!! Couldn’t believe our luck
We are about to leave for a week’s holiday, driving to Sydney about 1400km away to see my folks. With the interstate move and then the virus border closures, it been three years
I picked up some smaller Logitech 2.1 systems hoping to make a lil boom box with it for holiday music. I think it draws less then 500ma at 250v so been wondering about the possibility to trace its DC input and see if can be powered with a power bank via a dc-dc converter. I also have a couple of double brick size sealed deep cycle batteries and a really good charger for them as well as alternator charging while travelling. My Subaru XV is well equipped with a comprehensive JL Audio system. Although I cooked my front C3 woofers in the splits and running backup drivers there. I need to get the C3’s repaired or look into some pro grade drivers from PRV or DSI. I need strong 400hz to 80hz in the front stage and one of my fav songs is a woofer killer at pleasing volumes. Running too high a low pass filter on the fronts to protect the woofers kills the song. Most other songs in my playlist are similar
Touching on the reuse centre again, our Subaru XV is a bit short on luggage space . Found this at the centre, older tan model in perfect condition with a pair of aluminium cross beams. Keys for roof rack beams and pod included with spares!
https://www.rhinorack.com/en-au/pro...boxes/masterfit-roof-box-370l-black-_rmft370a
All that for $10!!! Couldn’t believe our luck
Nice score!
A new one costs a mere thousand bucks here in Canada.
The first two cars I owned, put together, cost about as much as one of these empty plastic boxes. 🙄
When did a giant piece of plastic Tupperware (TM) become so @!#*%! expensive?
-Gnobuddy
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Actually I love Tupperware. HDPE is one of my fav materials. We have a 6m catamaran, 4m catamaran, a 3.5m cathedral hull, all made from double walled marine buoyancy foam in HDPE. Takes any amount of abuse and no paint to worry about
With a million virus cases in Sydney, we decided at the last minute to give it a miss. Instead we are now having koffii in Airlie Beach Whitsundays area. After a day we’ll drive up to Townsville
With a million virus cases in Sydney, we decided at the last minute to give it a miss. Instead we are now having koffii in Airlie Beach Whitsundays area. After a day we’ll drive up to Townsville