I think this MDO Plywood is the stuff that is used by dB-draggers to build their subwoofer enclosures because of the very smooth finish and strength.
Isabelle
Isabelle
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Joined 2009
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I've found that I don't like working with MDF, it tends to blunt tools and it generates toxic dust.
Hi,
The first part explains extreme bass and extreme treble.
the bass unit gets no treble, the treble unit no bass.
But at the crossover point instead of sharing the current
like parallel, the same current flows through (diagram)
the tweeter and midbass, this balance condition is the
c/o point, no current flows between the point the two
drivers connect and the point the c/o components join.
(its almost like the c/o bits are not there at that frequency ...)
It may be difficult to understand.
It may help to think of the treble current going on way
and the bass current the other, at some point they cancel.
TinaTi may help : SPICE-Based Analog Simulation Program - TINA-TI - TI Tool Folder
its the easiest circuit emulator to use I've ever come across, also :
Series vs. Parallel Crossover Networks
TinaTi will show what is going on with proper equivalent circuits
of each driver, but I suspect that concept may be too difficult.
But its the way I concluded 1st order series will be better.
Yes the 4 ohm nominal crossover point values are the same.
rgds, sreten.
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Now I get it. Thanks for your patience to explain this to me.
I'll give it a try when the time is there for it. I guess a design with no tweeter is the perfect first project to try new things, since a fullranger won't crap out as fast as a tweeter when something is wrong with the filter 🙂
I just wonder, if the "tweeter" (in this case, the fullranger) has to be padded down (because it's more efficient than the woofer), then what happens?
You say that around the crossoverpoint, it's almost like the coil and cap isn't even there, but this means the resistors of the pad-down-network of the "tweeter" will also be in series with the "woofer", won't this pad the woofer down too so the speaker sounds the same as if there were no resistors in it, but less efficient?
Isabelle
I'll give it a try when the time is there for it. I guess a design with no tweeter is the perfect first project to try new things, since a fullranger won't crap out as fast as a tweeter when something is wrong with the filter 🙂
I just wonder, if the "tweeter" (in this case, the fullranger) has to be padded down (because it's more efficient than the woofer), then what happens?
You say that around the crossoverpoint, it's almost like the coil and cap isn't even there, but this means the resistors of the pad-down-network of the "tweeter" will also be in series with the "woofer", won't this pad the woofer down too so the speaker sounds the same as if there were no resistors in it, but less efficient?
Isabelle
Here's a thought.
41Hz Audio:AMP9 kit. 28V max, tall capacitors
Enough power (50w x4), and the extra channels allow you to go active.
41Hz Audio:AMP9 kit. 28V max, tall capacitors
Enough power (50w x4), and the extra channels allow you to go active.
Hi,
What you are saying is essentially true, and one of the advantages /
disadvantages of the series connection, things do get complicated
when the drivers impedances are different. However if you set the
"tweeter" level via an L-pad, then the bass unit will "see" the normal
tweeter load and all is hunky dory again.
FWIW as I've explained before due to sensitivity the TB is not better
than the SLS, its worse, and IMO the TB elliptical in a floor stander
mounted low (say 10L or so for the bass) is your best option.
Also FWIW a wide shallow speaker is relatively easy to extensively
brace, and 10mm or 12mm stock with intelligent bracing for this
case is IMO a lot better than using 20mm stock. for this case
possibly 18mm or 20mm stock for the baffle (rounded edges)
and then 10mm or 12mm stock extensively braced elsewhere.
Good design is the art of the best compromises.
There is still a lot to be said for using ply in a smallish design.
rgds, sreten.
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Isabelle and Xenia,
Don't even consider the TB 1139 woofer unless you are planning to buy a plate amp. Trust me on this one. If no plate amp is in the cards find another woofer. By the time you pad everything down it'll sound like a whisper and not a roar. Forget about how low it goes, if you were concerned about that, you wouldn't be using a 6.5". That is a wonderful little driver but will not ever satisfy you unless you get yourself a little plate amp. Don't go through the same disappointment I did. I've already done that for you. I only wish someone had given me a slap up the side of the head before I thought I could do what you now think you can do. You can't. That woofer doesn't even give you the 83 dB it claims until you're up in the part of the spectrum you don't want that woofer running in anyway. That woofer likes to go no higher than about 250Hz which is perfect for a plate amp with the built in XO for the FR's you have in mind. It's a win win. I use it in a similar situation and am very happy.
Don't even consider the TB 1139 woofer unless you are planning to buy a plate amp. Trust me on this one. If no plate amp is in the cards find another woofer. By the time you pad everything down it'll sound like a whisper and not a roar. Forget about how low it goes, if you were concerned about that, you wouldn't be using a 6.5". That is a wonderful little driver but will not ever satisfy you unless you get yourself a little plate amp. Don't go through the same disappointment I did. I've already done that for you. I only wish someone had given me a slap up the side of the head before I thought I could do what you now think you can do. You can't. That woofer doesn't even give you the 83 dB it claims until you're up in the part of the spectrum you don't want that woofer running in anyway. That woofer likes to go no higher than about 250Hz which is perfect for a plate amp with the built in XO for the FR's you have in mind. It's a win win. I use it in a similar situation and am very happy.
Things get even more complicated if you put a small resistor between
the two points previously mentioned, a favourite "tuning" trick of series
fans who like to confuse those used to parallel as much as possible 😉
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Chris661: I know about those 41Hz kits, but I don't have the skills and experience to build a diy-amp. It's just easier and better looking to buy a nice home-audio amp that matches the rest of the gear to power both the indoors and outdoors speakers, so I prefer a passive solution for this project.
sreten: If I replace the "tweeter" in that series-schematic by this (see below), and making sure the total impedance of this little network is the same as the impedance of the woofer, it should work just as good as if no padding was necessary?
Cal Weldon: The amp we'll use to power these speakers has an output of 2x85W RMS. Since these speakers don't need to get really loud, I guess that amount of power should be sufficient?
Isabelle
sreten: If I replace the "tweeter" in that series-schematic by this (see below), and making sure the total impedance of this little network is the same as the impedance of the woofer, it should work just as good as if no padding was necessary?
An externally hosted image should be here but it was not working when we last tested it.
Cal Weldon: The amp we'll use to power these speakers has an output of 2x85W RMS. Since these speakers don't need to get really loud, I guess that amount of power should be sufficient?
Isabelle
Ditto what Cal says about the TB-1139. I have several. Great little woofer that can work in very small box. BUT. It needs gobs of power to make any sound. Really best for an active amplification setup, like the plate amp.
According to WinISD, a single 1139 in 6liters sealed with 85W on it should produce 102dB in the 100-200Hz range and 82dB at 20Hz, knowing that there will be 2 speakers (+6dB), I don't see why this shouldn't be enough.
Semi-off-topic:
Before we bought that house and decided to keep only 1 car, I was planning to run 3 of those in both front doors of my car with about 200W per side (67W per driver) in a 3-ways subless setup.
In the car we'll keep, we'll use a single pair of CSS Trio8's for midbass+sub, but I am still considering using 4 of those TB W6-1139's in the rear-deck with 300W total on it (75W per driver)...
Isabelle
Semi-off-topic:
Before we bought that house and decided to keep only 1 car, I was planning to run 3 of those in both front doors of my car with about 200W per side (67W per driver) in a 3-ways subless setup.
In the car we'll keep, we'll use a single pair of CSS Trio8's for midbass+sub, but I am still considering using 4 of those TB W6-1139's in the rear-deck with 300W total on it (75W per driver)...
Isabelle
Hi Isabella,
Yes, your picture shows the L-pad arrangement.
Regarding your question to CW :
You are losing any grip on what amplifier power is about and the replay
levels you will be able to achieve, especially outdoors. If you build them
as I suggest your amplifier will be fine. If you use the TB and slug the
Vifa into submission your amplifier will not fine, by the time you get the
bass to start moving the midrange will start to clip all over the place.
The maximum replay level will be pathetic compared to the other options,
and you will not be able to use the capabilities of the TB unit at all, the
amplifier will give up far before your exploring the TB parameters you like.
(As I said ages ago, and has been repeated, the TB needs its own amplifier.)
rgds, sreten.
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I'v read that you plan to place these speakers against the wall although you'd actually prefer not to do it.
Why not design a box that is intentionally made to be placed against a wall ? I.e. that wouldn't be a "box" in a usual sense anymore but something that makes smooth transitions to the wall. That way you would have mininmal baffle step to deal with and minimal influence in the midrange as well.
Regards
Charles
Edit: Had to write out baffle step since the language filter didn't like its short form ;-)
Why not design a box that is intentionally made to be placed against a wall ? I.e. that wouldn't be a "box" in a usual sense anymore but something that makes smooth transitions to the wall. That way you would have mininmal baffle step to deal with and minimal influence in the midrange as well.
Regards
Charles
Edit: Had to write out baffle step since the language filter didn't like its short form ;-)
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Well, we were thinking about making simpel rectangular boxes and mount them with U-brackets against the wall. This way we can mount them high and aim them down a bit, so the path lengths become longer, reducing the path length differences and reducing the difference between the listening angles when sitting/standing at different spots of the bbq-spot.
Speaker enclosures that have smooth transitions to the wall would require them to be taller and wider and would propably look weird.
You do mean something like this, don't you?
(not to scale)
Speaker enclosures that have smooth transitions to the wall would require them to be taller and wider and would propably look weird.
You do mean something like this, don't you?
(not to scale)
Attachments
Another idea:
would it be possible to hide the subs? That way, you could use a potentially larger cabinet, expanding choices to 8" woofers (better efficiency etc available). You'd need a 4" FR driver to get to 100Hz comfortably, but I figure this idea would give more flexibility...
would it be possible to hide the subs? That way, you could use a potentially larger cabinet, expanding choices to 8" woofers (better efficiency etc available). You'd need a 4" FR driver to get to 100Hz comfortably, but I figure this idea would give more flexibility...
That might be a possibility, but if we'd choose to use (a) seperate subwoofer(s), we'd do this in the future and now build a pair of speakers that can play well (but without the bass-extention) on their own.
If we'd choose this route, the budget goes down: For about 200 Euros, we can buy a pair of ready made out-door speakers, so we wanted to build our own outdoor speakers for the same budget, but with better bass extention, if better bass extension isn't possible, we want to be done for a lower amount of money.
If we'd go the "no sub-bass" route, I was thinking about the TangBand W6-623C as a woofer, still combined with the Vifa fullranger.
It would make more sense to choose a smaller fullranger or even a tweeter, but that doesn't make sense if this is more expensive than the Vifa.
This way, it's possible to cross at the baffle-step frequency, since the 623 can easily play up to a few kHz and the Vifa can play easily down to 200Hz, so there's a very wide range to choose a crossoverpoint within...
Isabelle
If we'd choose this route, the budget goes down: For about 200 Euros, we can buy a pair of ready made out-door speakers, so we wanted to build our own outdoor speakers for the same budget, but with better bass extention, if better bass extension isn't possible, we want to be done for a lower amount of money.
If we'd go the "no sub-bass" route, I was thinking about the TangBand W6-623C as a woofer, still combined with the Vifa fullranger.
It would make more sense to choose a smaller fullranger or even a tweeter, but that doesn't make sense if this is more expensive than the Vifa.
This way, it's possible to cross at the baffle-step frequency, since the 623 can easily play up to a few kHz and the Vifa can play easily down to 200Hz, so there's a very wide range to choose a crossoverpoint within...
Isabelle
Hi,
A few points :
Mounting them high outside will take away the bass boost effect
you would get with a floorstander with a low mounted bass unit.
TangBand W6-623C
It is a better choice due to the sensitivity.
At it is the 30L Vas, Fs 46Hz implies a lightweight cone.
It really needs around 10L sealed not the 5L you are planning.
Using it and mounting it high would be really giving up on any bass.
TBH its a bass/mid much more than a bass unit.
The TB 6x9 sub has the same Vas, lower Fs, lower Q but with
less sensitivity. It will work into the same volumes as the above.
Larger cone area and nearly double the excursion capability it
not to be sneezed in my book.
Its bass power handling is far superior to the above.
If the point is to make a reasonable attempt at reggae or house
music outside, you should use all the acoustics advantages you
can to maximise the bass levels, they will quickly die away as
you move away from the speakers due to being outside.
Floor/wall corner loading of the bass unit should be considered.
All the design indicators point to shallow near wall floorstander
with a low mounted bass unit, vifa optimally placed near the
top, c/o still around what would be the baffle width frequency.
A stone base should help getting it near the wall. It does not
have to be a floorstander, it could be tall and mounted on
the wall, as long as the bottom bass unit is near the floor.
rgds, sreten.
A few points :
Mounting them high outside will take away the bass boost effect
you would get with a floorstander with a low mounted bass unit.
TangBand W6-623C
It is a better choice due to the sensitivity.
At it is the 30L Vas, Fs 46Hz implies a lightweight cone.
It really needs around 10L sealed not the 5L you are planning.
Using it and mounting it high would be really giving up on any bass.
TBH its a bass/mid much more than a bass unit.
The TB 6x9 sub has the same Vas, lower Fs, lower Q but with
less sensitivity. It will work into the same volumes as the above.
Larger cone area and nearly double the excursion capability it
not to be sneezed in my book.
Its bass power handling is far superior to the above.
If the point is to make a reasonable attempt at reggae or house
music outside, you should use all the acoustics advantages you
can to maximise the bass levels, they will quickly die away as
you move away from the speakers due to being outside.
Floor/wall corner loading of the bass unit should be considered.
All the design indicators point to shallow near wall floorstander
with a low mounted bass unit, vifa optimally placed near the
top, c/o still around what would be the baffle width frequency.
A stone base should help getting it near the wall. It does not
have to be a floorstander, it could be tall and mounted on
the wall, as long as the bottom bass unit is near the floor.
rgds, sreten.
Okay...
Different approach: floorstanders that aren't wider and deeper than the speakers we were planning to build, but a lot taller (so the fullrangers are somewhere between the sitting-down and standing-up ear-level).
This way, we can create a lot more volume for the woofers ànd for the fullrangers.
By the way: I discovered the amp we are planning to buy isn't 85W RMS per channel at 4 ohms, but at 8 ohms and 100W RMS per channel at 6ohms. It is 4ohms stable, but then it'll probably give "only" the same 100W RMS as it does at 6ohms, so maybe the 1139 might become possible?
Isabelle
Different approach: floorstanders that aren't wider and deeper than the speakers we were planning to build, but a lot taller (so the fullrangers are somewhere between the sitting-down and standing-up ear-level).
This way, we can create a lot more volume for the woofers ànd for the fullrangers.
By the way: I discovered the amp we are planning to buy isn't 85W RMS per channel at 4 ohms, but at 8 ohms and 100W RMS per channel at 6ohms. It is 4ohms stable, but then it'll probably give "only" the same 100W RMS as it does at 6ohms, so maybe the 1139 might become possible?
Isabelle
Hi,
The issue with the 1139 is how much you have to slug the midrange,
and in doing that to get the drive to the 1139 the midrange will clip.
Most of the power is in the bass, for your amplifier you want a 8 ohm unit.
Level control on the Vifa should be a series resistor rather than an L-pad.
A triangular section in the top is the easiest way to enclose it. Series
should still work well with with a 2:1 driver impedance ratio though
the details are subtlely different.
If the speakers are going to be very close to walls then the wider and
less deep you make them the less the midrange cancellation issues,
and the lower the c/o frequency that works well will be, for other
reasons depth = width is not a good idea anyway.
As its not a 4 ohm amplifier the twin 8 ohm driver concept is not so good.
The TB 6x9 8ohm seems to fit the bill and it needs around 10L stuffed.
It will need the silicone spray treatment I assume.
I'd say your looking at 3L or so for the vifa and a total internal of say 13L.
rgds, sreten.
The issue with the 1139 is how much you have to slug the midrange,
and in doing that to get the drive to the 1139 the midrange will clip.
Most of the power is in the bass, for your amplifier you want a 8 ohm unit.
Level control on the Vifa should be a series resistor rather than an L-pad.
A triangular section in the top is the easiest way to enclose it. Series
should still work well with with a 2:1 driver impedance ratio though
the details are subtlely different.
If the speakers are going to be very close to walls then the wider and
less deep you make them the less the midrange cancellation issues,
and the lower the c/o frequency that works well will be, for other
reasons depth = width is not a good idea anyway.
As its not a 4 ohm amplifier the twin 8 ohm driver concept is not so good.
The TB 6x9 8ohm seems to fit the bill and it needs around 10L stuffed.
It will need the silicone spray treatment I assume.
I'd say your looking at 3L or so for the vifa and a total internal of say 13L.
rgds, sreten.
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