The wait for new oscilloscope and procrastination is killig me.
So I got a new idea in the endless chain of very stupid ideas. Making a sleeper subwoofer design, that looks weak, but sounds unexpectedly mighty for the looks.
It should be rather compact looking design or halfway in-built design into the wide "office table leg".
The idea is either a tapped horn looking style, with weak 6"-ish driver magnet exposed for view, or ported design with unimposing frontward facing 6" cone sticking out for view.
The true drivers will be one of the three:
1) Logitech Z-2300 woofer driver (basically respected 8" Tang-Band driver).
2) Mid grade 8" car audio driver with even more oomph (Hadex 338).
3) something new from Soundimports.eu
Where I'm lost is to find best decoy driver (could be a passive radiator too), making it plausible by looks, and making it move when the design is working, either electrically or as a passive radiator, that needs to be managed to not get overwhelmed by the strong driver in the background.
Ideas welcome!
So I got a new idea in the endless chain of very stupid ideas. Making a sleeper subwoofer design, that looks weak, but sounds unexpectedly mighty for the looks.
It should be rather compact looking design or halfway in-built design into the wide "office table leg".
The idea is either a tapped horn looking style, with weak 6"-ish driver magnet exposed for view, or ported design with unimposing frontward facing 6" cone sticking out for view.
The true drivers will be one of the three:
1) Logitech Z-2300 woofer driver (basically respected 8" Tang-Band driver).
2) Mid grade 8" car audio driver with even more oomph (Hadex 338).
3) something new from Soundimports.eu
Where I'm lost is to find best decoy driver (could be a passive radiator too), making it plausible by looks, and making it move when the design is working, either electrically or as a passive radiator, that needs to be managed to not get overwhelmed by the strong driver in the background.
Ideas welcome!
It is not going very fast, but it is going. Today the decoy driver got "angle grinder treatment" for possible tuning, and the 8" got hidden in the box.
Rest assured that it will be presented as a mighty tapped horn with 5,5" driver giving monstrous output. Wanna see some heads turning.
Build ongoing. The raw woodwork is terrible, but I expect it to look quite nice from the outside when I´m done with it.
The inner clean box volume is very small, so I am fighting the tune on the go. It will probably end up tuning 2-3Hz higher than expected - about 37-38Hz.
Not sure if it will add to the Tapped Horn prestige or take from it, but that´s life.
Last time I made a proof of concept Tapped horn with true (but weak) speaker, I was very impressed what can be done with a terrible driver. The output was strong and down to 33Hz, but it is not feasible to make 25kg large box for weak 6,5". Makes no sense, to spend all the materials and time. So, that´s why I´m here now.
Build ongoing. The raw woodwork is terrible, but I expect it to look quite nice from the outside when I´m done with it.
The inner clean box volume is very small, so I am fighting the tune on the go. It will probably end up tuning 2-3Hz higher than expected - about 37-38Hz.
Not sure if it will add to the Tapped Horn prestige or take from it, but that´s life.
Last time I made a proof of concept Tapped horn with true (but weak) speaker, I was very impressed what can be done with a terrible driver. The output was strong and down to 33Hz, but it is not feasible to make 25kg large box for weak 6,5". Makes no sense, to spend all the materials and time. So, that´s why I´m here now.
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Without any tuning, just roughly assembled together before going to sleep.:
The Modecom now passive driver adds interesting resonance. In the morning, I might try to put some power to it to see how it moves.
I am very happy with the tuning at 36Hz. though I have grinded one part of the port to make it knowingly lower. Padding might take 2Hz off, for the tune I wished for.
The Modecom now passive driver adds interesting resonance. In the morning, I might try to put some power to it to see how it moves.
I am very happy with the tuning at 36Hz. though I have grinded one part of the port to make it knowingly lower. Padding might take 2Hz off, for the tune I wished for.
As expected, It eats some bass, gets overwhelmed and sounds real bad. So, back surface area needs to be heavily reduced and resonance probably setup the same as the port resonance.
For the moment even if I brake the small cone with hand or leg, the speaker does not sound. Good. I wonder if something else is going on. 😭
For the moment even if I brake the small cone with hand or leg, the speaker does not sound. Good. I wonder if something else is going on. 😭
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Yes... it's unloading the main driver and messing up the system response.
There are only 2 ways this can work..
1. the dummy must be in a fully isolated chamber and just be there for looks
2. It must be powered and in sync with the main driver but at a lower power level, but you need a complete driver not a passive radiator.
There could also be a third option but again you need to use a complete driver, with the terminals shorted (and not connected to the amp) the motor resists cone movement. That should work almost a good as having the driver 100% isolated but the cone may give out eventually, it;s just paper and not as rigid as the enclosure walls.
Well one could certainly combine.
I put some weight onto the cone and now I am really confused. I thought it would tune-in, but it does something different. it fights with the port now:
...Or whatever else it does...
So while I do have a second piece with magnet still, I put it in instead, with shorted terminals:
Much better. Though the first driver got the passive treatment because something went sideways, and it started to play less. With just shorted leads I believe I could even overwhelm the coil or burn it. So, solution details oncoming...
Compared to my other builds, it needs 3dB more persuation in the EQ department to still sound borderline (high standards), but some additional sealing, stiffening, padding and deadening wight help. And certainly the decoy speaker will get Sd restriction. Will seal its sides off mostly, so only fraction of the pressure is working on it. If it finally turns out usable, then I might finish the external looks.
I put some weight onto the cone and now I am really confused. I thought it would tune-in, but it does something different. it fights with the port now:
...Or whatever else it does...
So while I do have a second piece with magnet still, I put it in instead, with shorted terminals:
Much better. Though the first driver got the passive treatment because something went sideways, and it started to play less. With just shorted leads I believe I could even overwhelm the coil or burn it. So, solution details oncoming...
Compared to my other builds, it needs 3dB more persuation in the EQ department to still sound borderline (high standards), but some additional sealing, stiffening, padding and deadening wight help. And certainly the decoy speaker will get Sd restriction. Will seal its sides off mostly, so only fraction of the pressure is working on it. If it finally turns out usable, then I might finish the external looks.
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Is this basically a dual port system with one as a designed in TH type and the other (the decoy thingy) highly random and unoptimised......?
I do not have this problematics "walked through". I thought that two such resonators might more partially act as one in the sense altering each others properties rather greatly. But it looks like they can work pretty separately. Just a mistake on the imagination. No biggie. With shorted out voice coil it behaves fairly good, so hopefully when I restrict the passive radiator "input area" from within the box, I think it will be doing what I need it to. Might make the short on the decoy driver coil milder too, with 0,5-1Ohm resistor. After I touch up and finetune everything, it has good chance of working. And While it is still restricted design, for the 5,5" it sounds comically overpowered already. Heads will explode when people see and hear it as long as they don´t realize the joke. Which will sooner or later happen.... But it is very enjoyable project. I must make more of these one-odd abominations. Ideas welcome. 😛
I like this, but had poor results with desk vibrations when I tried. How about make the port a decoy?
This comes to mind.......
Your table wide leg as an enclosure for a pancake driver like this one
PSW10.4S
Where the desk top sits over the wide leg to form the top panel, run a thru port (throat adapter thingy) to a 6.5" cubic box pretending to sit on top of the desk with a short segment of the port visually effected to look like a circular plinth under that small box. Fit a fake slot port along the front baffle of that small box. Mount dual opposed 6" PR units on the box, front and rear panel
It should appear as a small PC type 2.1 sub sitting on the desk
Is the 'PR' getting bellowed out by the direct back radiation? Maybe slow it down by running a PR onto a PR. So the active driver volume activates the first PR and that in turn activates the second. Sort of like an isobaric but spaced out
So... I pulled the box out. With any hint of "8" serious work, the Modecom 5,5" driver choked immediatelly and started to resonate badly, because after all, it is a very bad driver as is. So on top of managing driver input area from within the box, I am sure that this driver is not a presentable unit.
Better driver has to be placed in instead. Ideas - welcome again...
Yes, I already need "a table leg". Not wide but rather deep, but same thing. Only issue is that it will be sitting in the room full of various subwoofers. Some kind of living room idea could be brewing, but it will get more complex with tops and amplification. But I already have it in my head, so no denial here. Just maybe some postponing. Thanks for upping that into relevance again.
But it rather happens near tuning, when the port is moving tremendous amount of air, possibly more than the driver itself, so there is no point in utilizing its output. It rather stay in the background and quiet when "men are speaking" 🙂
Better driver has to be placed in instead. Ideas - welcome again...
Yes, I already need "a table leg". Not wide but rather deep, but same thing. Only issue is that it will be sitting in the room full of various subwoofers. Some kind of living room idea could be brewing, but it will get more complex with tops and amplification. But I already have it in my head, so no denial here. Just maybe some postponing. Thanks for upping that into relevance again.
There is only one PR for space reasons, and it´s not even supposed to be PR. It is supposed to move a bit to bait people into thinking it´s a functional unit. I have no intention to make it a working driver. A 5,5" with 5mm Xmax has "NOTHING" on 8" that can stretch to +-20mm when angry.
But it rather happens near tuning, when the port is moving tremendous amount of air, possibly more than the driver itself, so there is no point in utilizing its output. It rather stay in the background and quiet when "men are speaking" 🙂
What if you placed it in path of the port? Like an Enterprise deflector dish in the middle of the port flare. In the flow but not completely blocking
What you mean exactly? I thought I already did that. See third post (second image). The base port dimensions are 19 x 4,6cm rectangle. So this big mouth opening makes it to be rather "to the port side mount" when considering the port. The port does not have a problem at all. The inner box pressure cause this driver to overload easily. The 8" is really quite a unit, very short of big car motofoko SPL drivers. Has Bl 15, that´s where quite many 12"s normally sit. I tried to hold down the Modecom by my hand, and with some power going to the driver, i was not successfull.
You didn't, the PR is exposed to the active driver's back pressure on one side. I meant to place the PR wholly in the flow of the port only with the port exit flaring around the PRs rim. The PR can be mounted in a printed frame fitting over the port flare. It might catch enough of that oscillating pocket of port air to move a bit. If you still dont get it, imagine a car audio coax 2-way. The tweeter and its mounting would be the decoy and the woofer cone area would be the port exit. Hope it makes sense
Oh, now it does make sense. Well, more thought would have to be put into such design, because "just like that" it would be probably way too fake and way off base in the Tapped Horn design look. The current situation looks really convincing. When I touch the passive, it moves a lot, with a lot of force. It would almost be okay if that happened at full 8" SPL, but it happens in the 1/10 -1/4 of power range. Need to just lessen the ratio, and use a driver that is behaving more admirably in excursion than this low end unit. Looking at some Peerless and contemplating on Tang-Band. But that one is more expensive now than the 8".
Cool Idea shorting the fake one out with a resistor to dial it in !
What the actual ‘tapped horn’ design look like inside ? Long THAM like shape?
What the actual ‘tapped horn’ design look like inside ? Long THAM like shape?
Yes it helps a lot, but still not enough. The 8" is just too mighty. It ragdolls the weak Modecom. Better driver with restricted Sd needed.
No, it is only supposed to look like tapped horn from the outside. While it is somehow known that tapped horns can produce a lot of sound, and they do, I want to ride that idea way overboard, by just looking somewhat like it. The basic look is to be seen on my second picture of this topic.
Inside, it is pure(although long) bassreflex. The driver sits at the bottom of the enclosure, mounted as to the "front" as possible, and the port goes from this "tapped horn mouth" around the top-back-bottom wall as far as possible. The inside chamber will be about 15-16 liters of volume. Wait, lemme make a funny photo:
Something along the lines of that.
I think you still didn't realize full scope of my sickness and idiocy. 😂
It is just too irrational.
But it almost works. I believe that with better decoy driver, air restriction to the cone, padding, deadening and finetuning it will do what I ask it to do.
No, it is only supposed to look like tapped horn from the outside. While it is somehow known that tapped horns can produce a lot of sound, and they do, I want to ride that idea way overboard, by just looking somewhat like it. The basic look is to be seen on my second picture of this topic.
Inside, it is pure(although long) bassreflex. The driver sits at the bottom of the enclosure, mounted as to the "front" as possible, and the port goes from this "tapped horn mouth" around the top-back-bottom wall as far as possible. The inside chamber will be about 15-16 liters of volume. Wait, lemme make a funny photo:
Something along the lines of that.
I think you still didn't realize full scope of my sickness and idiocy. 😂
It is just too irrational.
But it almost works. I believe that with better decoy driver, air restriction to the cone, padding, deadening and finetuning it will do what I ask it to do.