Hi Folks (I'm new here, check the introduction section)!
Me and my girlfriend will be moving to a bought house (after renting an apartment for a while) very soon.
This means we will finally be able to sit outside and have a BBQ when the weather allows it.
We are both people that cannot live a day without music, but it has to sound good to enjoy it, so a set of good sounding speakers would be a HUGE improvement for our garden and barbecue spot.
Now, since we don't want to drag a pair of speakers in and out all the time, we want a pair of great sounding speakers that can be left outside.
The most logical way would be to buy a pair of garden/marine speakers and be done with it, but since most outdoor speakers are built around a midwoofer+tweeter and we like to listen to reggae from time to time, especially when chilling outside, we prefer a Fullrange And Subwoofer Technology system.
This way, we have a pair of small subwoofers with good low-end extension combined with the nice pure sound of a full-range driver.
It seams something like this doesn't exist ready-made, so this means: DIY!
We don't want huge speakers, so 20cm (8") width x 20cm (8") depth x 35cm (14") height is the maximum size we want.
I was thinking about the Vifa TG9FD10/04 as the full-range drivers. Those aren't marine/outdoor drivers, but with their fiberglass cone, rubber surround and ABS basket, I guess they should do the trick and survive rain showers...
The problem is the subwoofer. Because of the limited size of the speakers, the subwoofer can't be bigger in diameter than 6.5". Something like the Peerless SLS6.5 or TangBand W6-1139 should be perfect for the job, but both these drivers have a paper-cone:
- Would it hurt the parameters and sound of the mini-subwoofers a lot if I coated them with something that protects the paper-cone from rain showers? I think about 200Hz would be a good crossoverpoint between a mini-sub and the Vifa TG9, so it doesn't matter if a coating has a negative influence on the sound of the mini-subs above that point.
- Are there any other mini-subs (6-6.5" diameter, minimum 8mm's of x-max) that are affordable and can play well in a small sealed enclosure that have a cone (ànd surround!) that is made out of materials that are more water-resistant?
Isabelle
Me and my girlfriend will be moving to a bought house (after renting an apartment for a while) very soon.
This means we will finally be able to sit outside and have a BBQ when the weather allows it.
We are both people that cannot live a day without music, but it has to sound good to enjoy it, so a set of good sounding speakers would be a HUGE improvement for our garden and barbecue spot.
Now, since we don't want to drag a pair of speakers in and out all the time, we want a pair of great sounding speakers that can be left outside.
The most logical way would be to buy a pair of garden/marine speakers and be done with it, but since most outdoor speakers are built around a midwoofer+tweeter and we like to listen to reggae from time to time, especially when chilling outside, we prefer a Fullrange And Subwoofer Technology system.
This way, we have a pair of small subwoofers with good low-end extension combined with the nice pure sound of a full-range driver.
It seams something like this doesn't exist ready-made, so this means: DIY!
We don't want huge speakers, so 20cm (8") width x 20cm (8") depth x 35cm (14") height is the maximum size we want.
I was thinking about the Vifa TG9FD10/04 as the full-range drivers. Those aren't marine/outdoor drivers, but with their fiberglass cone, rubber surround and ABS basket, I guess they should do the trick and survive rain showers...
The problem is the subwoofer. Because of the limited size of the speakers, the subwoofer can't be bigger in diameter than 6.5". Something like the Peerless SLS6.5 or TangBand W6-1139 should be perfect for the job, but both these drivers have a paper-cone:
- Would it hurt the parameters and sound of the mini-subwoofers a lot if I coated them with something that protects the paper-cone from rain showers? I think about 200Hz would be a good crossoverpoint between a mini-sub and the Vifa TG9, so it doesn't matter if a coating has a negative influence on the sound of the mini-subs above that point.
- Are there any other mini-subs (6-6.5" diameter, minimum 8mm's of x-max) that are affordable and can play well in a small sealed enclosure that have a cone (ànd surround!) that is made out of materials that are more water-resistant?
Isabelle
Hi, Given your size constraint, it is going to be hard to get particularly much output out of a small sealed box.
My suggestion would be to use a T-TQWT or Tapped Horn, which allow you to get a lot of output, even using small drivers like 6.5"ers. You won't find one that entirely matches your size dimensions, but you could probably find something with a similar footprint - but taller.
Here's an image showing what I'm talking about:
There are other people on this forum who know alot more about the actual acoustic characteristics than me (bjorno for example), but one of the reasons why I suggest this design is because the driver is in the inside of the enclosure, and not on the outside, exposed to the elements. If you cover the opening with a fairly tightly spaced grill, that should keep any water from raining in, and leaves just condensation dew and the like to consider.
Just a thought.
My suggestion would be to use a T-TQWT or Tapped Horn, which allow you to get a lot of output, even using small drivers like 6.5"ers. You won't find one that entirely matches your size dimensions, but you could probably find something with a similar footprint - but taller.
Here's an image showing what I'm talking about:
There are other people on this forum who know alot more about the actual acoustic characteristics than me (bjorno for example), but one of the reasons why I suggest this design is because the driver is in the inside of the enclosure, and not on the outside, exposed to the elements. If you cover the opening with a fairly tightly spaced grill, that should keep any water from raining in, and leaves just condensation dew and the like to consider.
Just a thought.
You can coat the woofers... with the right stuff they usually get better. What is use is water soluable (PVA & Acrylic) so isn't the best solution for outdoors.
Also consider the Mark Audio CHR-70 (also available in Germany as an Omnes if you prefer black), metal cone, rubber surround, plastic basket.
One further comment, probably not a good idea to make the boxes out of MDF.
dave
Also consider the Mark Audio CHR-70 (also available in Germany as an Omnes if you prefer black), metal cone, rubber surround, plastic basket.
One further comment, probably not a good idea to make the boxes out of MDF.
dave
i.e. regardless of the recursive debates that might easily be encountered as to why some folks (myself included) would avoid MDF for almost any speaker enclosure, the standard varieties are particularly ill-suited to moisture prone environs.
there are of course several grades of exterior rated sheet goods (medex / MDO) etc., that would be far more durable, but availability in your local area could be spotty
and it wouldn't hurt to treat any exposed edges and joints with liberal application of penetrating epoxy resin or exterior grade spar varnish.
Well hello there,
I'm Isabelle's girlfriend and thought I'd comment here.
She's gonna use a layer of poly resin on the inside and out of the enclosure to seal it off, which in our opinion should suffice... If not, we can always resort to coating it with a few layers of glassfiber.
Xenia
I'm Isabelle's girlfriend and thought I'd comment here.
She's gonna use a layer of poly resin on the inside and out of the enclosure to seal it off, which in our opinion should suffice... If not, we can always resort to coating it with a few layers of glassfiber.
Xenia
I don't have any experience with transmission-line speakers, (well, our B&W DM2a are TL speakers, but we didn't build those ourselves) and since the size limitations, I'd rather not use this project to give it a try.
I'd rather try a TL design later and start with the basics for this outdoors project: sealed enclosures with simple passive crossovers.
About the Markaudio CHR70: Since we'll have a bunch of other things to spend money on (new couches, new freezer, new airconditioning and heating system...), we want to keep this project as low-budget as possible.
The fullrangers will be supported by mini-subs, so the extra linear excursion of the CHR70 compared to the Vifa TG9 isn't necessary. I also wanted to try the Vifa TG9's for quite a while and this project is the ideal excuse to do it, and they're cheaper than the MarkAudio's, so I'm 99% sure the Vifa TG9's will be the fullrangers for this project, unless somebody can give me a very good reason not to use them for this?
MDF isn't the best material to make something that will be put outside, exposed to water, but as Xenia already said, I'll be sealing the enclosures with polyester resin and probably add a layer of glassfiber + extra polyester resin on the outside, so the MDF won't "see" any water or humidity.
Coating the woofers with something that is solvable in water isn't a very good idea for this project indeed. I was thinking of coating them with some kind of resin or waterproofing stuff?
Isabelle
I'd rather try a TL design later and start with the basics for this outdoors project: sealed enclosures with simple passive crossovers.
About the Markaudio CHR70: Since we'll have a bunch of other things to spend money on (new couches, new freezer, new airconditioning and heating system...), we want to keep this project as low-budget as possible.
The fullrangers will be supported by mini-subs, so the extra linear excursion of the CHR70 compared to the Vifa TG9 isn't necessary. I also wanted to try the Vifa TG9's for quite a while and this project is the ideal excuse to do it, and they're cheaper than the MarkAudio's, so I'm 99% sure the Vifa TG9's will be the fullrangers for this project, unless somebody can give me a very good reason not to use them for this?
MDF isn't the best material to make something that will be put outside, exposed to water, but as Xenia already said, I'll be sealing the enclosures with polyester resin and probably add a layer of glassfiber + extra polyester resin on the outside, so the MDF won't "see" any water or humidity.
Coating the woofers with something that is solvable in water isn't a very good idea for this project indeed. I was thinking of coating them with some kind of resin or waterproofing stuff?
Isabelle
Isabelle,
I didn't offer any suggestions of something waterproof as i have no experience with anything. Whatever you use you want it to add little mass and to remain somewhat flexible after curing. The 1st things that come to mind, rubber cement or silicon, can not likely be applied thin enuff to be effective, it might be possible to thin the rubber cement, or to find a more usable silicon compound.
As to MDF, i've seen a lot of it "explode" under the assault of the local monsoons, sealed or not. If you are going to fiberglass anyway, why not just use foamcore as a base? (with a multiply or aluminum baffle). A fiberglass skin (both sides) does go a long way to dealing with MDF's sonic inadequacies.
dave
I think you might have issues with non-flexible resins that would be suitable for treatment of the enclosures. Notwithstanding the effect of additional mass on sensitivity and Fs, they'd likely seriously affect both the compliance of surrounds and the sonic performance of the cone material (whether paper or plastic based)
It could well be easier to moisture proof the boxes than drivers not specifically intended for such an application, and you might well be advised to consider speakers designed for marine or rugged outdoor use. But if you want to use existing drivers, a quick google and forum search suggests that silicone based spray-on moisture guards (as for fabric / leathers) would be a simple solution (might need occasional re-application)
Hi,
Just some observations :
Clear acrylic should be good for protecting cones.
200Hz seems a little low for the c/o point. As its outdoors you'll want
full baffle step compensation. One way of doing this is make the bass
end 6dB more efficient than the mid/treble and then use a simple
(series?) crossover around the baffle step point to meld the drivers.
A cheap (Apex Jr Audax $1) supertweeter cannot do much harm.
To get this sort of efficiency in the bass your not really looking at
subwoofers IMO, unless you will actually go around 200Hz and EQ
back the Vifa at the the top end to balance the BSC issues.
A couple of 6.5 bass/ mid drivers 8ohm in parallel, with each one
on its own the same senstivity as the Vifa should do the job.
Putting them on opposite faces will give some force cancelling.
Car drivers are essentially moistureproof and many hifi drivers are built
the same way. As the Vifa is $30 or so a two high value poly drivers
are IMO the way to go, but I'm not sure where you can buy from,
so suggesting cheap drivers is difficult.
Two 6.5's with good efficiency in a small box are not going to do low
bass, but you will have the power handling and cone area for some
low bass boost if required, but all domestic speakers struggle outside
a room with low bass, outside a serious subwoofer is needed and
you need to be close to it.
6.5"x6.5"x12.5" internal is not a lot, 1/3 cuft, 8.5L, perhaps a floorstander ?
If you keep it small two 5" bass drivers are as large as you can go IMO.
1/2" stock gives you 10L or so to play with.
For your application the sealed Q should be around 0.8/0.9 IMO.
Where can you source drivers ?
There some cheap Peerless stuff around at the moment.
rgds, sreten.
Just some observations :
Clear acrylic should be good for protecting cones.
200Hz seems a little low for the c/o point. As its outdoors you'll want
full baffle step compensation. One way of doing this is make the bass
end 6dB more efficient than the mid/treble and then use a simple
(series?) crossover around the baffle step point to meld the drivers.
A cheap (Apex Jr Audax $1) supertweeter cannot do much harm.
To get this sort of efficiency in the bass your not really looking at
subwoofers IMO, unless you will actually go around 200Hz and EQ
back the Vifa at the the top end to balance the BSC issues.
A couple of 6.5 bass/ mid drivers 8ohm in parallel, with each one
on its own the same senstivity as the Vifa should do the job.
Putting them on opposite faces will give some force cancelling.
Car drivers are essentially moistureproof and many hifi drivers are built
the same way. As the Vifa is $30 or so a two high value poly drivers
are IMO the way to go, but I'm not sure where you can buy from,
so suggesting cheap drivers is difficult.
Two 6.5's with good efficiency in a small box are not going to do low
bass, but you will have the power handling and cone area for some
low bass boost if required, but all domestic speakers struggle outside
a room with low bass, outside a serious subwoofer is needed and
you need to be close to it.
6.5"x6.5"x12.5" internal is not a lot, 1/3 cuft, 8.5L, perhaps a floorstander ?
If you keep it small two 5" bass drivers are as large as you can go IMO.
1/2" stock gives you 10L or so to play with.
For your application the sealed Q should be around 0.8/0.9 IMO.
Where can you source drivers ?
There some cheap Peerless stuff around at the moment.
rgds, sreten.
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The clothing-waterproofing-stuff is something that's been suggested on another forum where I asked this question too, so I guess I'll go with that stuff.
I don't mind re-applying it once in a while. We'll probably get the speakers inside in the winter (water is one thing, but I think ice is a lot worse for any material), so it's not too much of trouble to re-coat the woofers when bringing them back outside at spring-time...
Isabelle
I don't mind re-applying it once in a while. We'll probably get the speakers inside in the winter (water is one thing, but I think ice is a lot worse for any material), so it's not too much of trouble to re-coat the woofers when bringing them back outside at spring-time...
Isabelle
Hi,
Well two of these per cabinet, in parallel :
830656 - Peerless SDS-134-THP 5.5 inch woofer coated paper - Europe Audio
Being coated they should be effectively sealed, from the front at least.
Model fairly well for a well stuffed sealed cabinet around 8.5L, they will
give you a Q around 0.85 to 0.9. Bass will roll off fairly early but you
cannot argue with the laws of physics. They are good value drivers.
Sensistivity is not quite enough for full baffle step but they still will be
a lot better than a single driver of the same sensistivity as the Vifa.
Experimenting with say 0.5R to 1R in series with the Vifa may be
worthwhile if you are particular about a nice overall balance.
The larger 6.5* drivers are also good value but you'd need bigger
cabinets for two of these, around twice the internal volume.
A series 1st order crossover should work a lot better that 1st parellel.
Are remarkably good as supertweeters for FR drivers.
Tip : build your cabinets with a triangular section from the top back
corner to just below the Vifa, forming a triangular cavity for it.
Just realised I had ignored this extra volume in my calculation.
At this size an extra 1" on width and depth or more depth helps a lot.
adding 30% internal volume. making width and depth not the same
helps avoid panel resonances being near the same frequencies.
AFAIK if you build it sealed and use waterproof glue you only have
to seal the outside. You could chuck into each cabinet those gel
sacs that absorb water, they can be reused if you bake them.
As said before if moisture gets into the end grain of MDF then
they can literally explode due to tensions in the joints. But
I would not be too precious about the internal details sealed.
Watered down waterproof wood glue can be used as a sealer
for the internal surfaces and all exposes edges, e.g. for the
driver cutouts and terminal cutouts. Chamfer your Vifa cutout e.g.
rgds, sreten.
Some useful links :
http://sites.google.com/site/undefinition/diy
http://www.zaphaudio.com
http://www.rjbaudio.com/
http://speakerdesignworks.com/
http://www.htguide.com/forum/showthread.php4?t=28655
http://www.humblehomemadehifi.com
http://www.troelsgravesen.dk/
http://www.quarter-wave.com/
http://www.frugal-horn.com/
http://www.linkwitzlab.com/
http://www.musicanddesign.com/
rgds, sreten.
rgds, sreten.
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The reason why I want a F.A.S.T. system is to have an as good as possible low-end extension, giving the total lack of room-gain and limited size.
Those Peerless SDS drivers are nice and cheap and not too big, so a TMM or MTM setup with those should be possible, but the volume displacement of 2 of those doesn't even come close to the volume displacement of a single TangBand W6-1139 or even the Peerless SLS6.5.
About the baffle step compensation: Will this be needed in this situation? The speakers will be mounted against a wall with very limited space between the wall and the back of the speakers (maybe an inch), so the bass notes can't really "wrap around" the speakers.
Isabelle
Those Peerless SDS drivers are nice and cheap and not too big, so a TMM or MTM setup with those should be possible, but the volume displacement of 2 of those doesn't even come close to the volume displacement of a single TangBand W6-1139 or even the Peerless SLS6.5.
About the baffle step compensation: Will this be needed in this situation? The speakers will be mounted against a wall with very limited space between the wall and the back of the speakers (maybe an inch), so the bass notes can't really "wrap around" the speakers.
Isabelle
Hi,
Ok, you've lost me, I do not know what a F.A.S.T. system is.
Yes of course the subs have larger volume displacement, that is their
job, but all the other parameters seem to me wrong, unless you go
for bi-amplified and feed the subs with the sort of power they need.
Flush wall mounting is good, but very near wall mounting for bass levels
with boxes introduces horrible midrange peaks and dips. If you have
say 4dB of BSC you can tune bass by rear wall distance but keep it a
reasonable distance to avoid the midrange horrors, or put another way
all box speakers sound better away from walls up to a point, irrespective
of their frequency balance, unless you have made them wide and shallow.
You could make them shallow with 45 degree side walls with a wider
back than the front if mounting right back up against a wall is wanted.
Or simply make the baffle width quite a lot larger than cabinet depth.
Then your best bass unit will change compared to the free field case.
Physics being physics your best bet would be a say 8" 4 ohm unit of
similar senstivity to the Vifa, or a 6.5" if you still want to keep it small.
But it sounds like tall, shallow, and wide baffle speakers are your
best bet ? Due to volume inefficiency (compared to a cube)
such speakers needs lots of wood for the enclosed volume.
Just as a thought checkout :
http://www.quarter-wave.com/OBs/OB_Design.pdf
Completely different but should work well outside (away from walls).
Driver weather resistance would be an issue.
rgds, sreten.
Ok, you've lost me, I do not know what a F.A.S.T. system is.
Yes of course the subs have larger volume displacement, that is their
job, but all the other parameters seem to me wrong, unless you go
for bi-amplified and feed the subs with the sort of power they need.
Flush wall mounting is good, but very near wall mounting for bass levels
with boxes introduces horrible midrange peaks and dips. If you have
say 4dB of BSC you can tune bass by rear wall distance but keep it a
reasonable distance to avoid the midrange horrors, or put another way
all box speakers sound better away from walls up to a point, irrespective
of their frequency balance, unless you have made them wide and shallow.
You could make them shallow with 45 degree side walls with a wider
back than the front if mounting right back up against a wall is wanted.
Or simply make the baffle width quite a lot larger than cabinet depth.
Then your best bass unit will change compared to the free field case.
Physics being physics your best bet would be a say 8" 4 ohm unit of
similar senstivity to the Vifa, or a 6.5" if you still want to keep it small.
But it sounds like tall, shallow, and wide baffle speakers are your
best bet ? Due to volume inefficiency (compared to a cube)
such speakers needs lots of wood for the enclosed volume.
Just as a thought checkout :
http://www.quarter-wave.com/OBs/OB_Design.pdf
Completely different but should work well outside (away from walls).
Driver weather resistance would be an issue.
rgds, sreten.
FAST is a full range with a helper woofer, XO usually 100-400 Hz. Most of the advantages of a FR without having to reproduce bass. Ideal for some of the really extended 3 & 4" FRs now available. Isabelle is looking for a system of similar concept to Tysen (this thread breaks off into a couple others using different drivers)
The little VIFA is unlikely to need any help on the top.
dave
The little VIFA is unlikely to need any help on the top.
dave
Hi,
Thanks for that, its the term rather than the concept I did not know.
I was thinking about better dispersion as an issue rather than extension.
But its simply an option to be considered (cheaply, perhaps with
a series 1st order c/o rather than simply running it in parallel.)
rgds, sreten.
tweeter link : http://www.apexjr.com/speakerstuff.html
(its apparently made by Audax, so unlike a lot of copies, its good.)
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I know putting a speaker against a wall without putting it *inside* the wall (baffle flush with the walls surface) is one of the worst things you can do with a speaker, but it's the only option we've got.
We are not willing to hack cavities into the outer walls for a couple speakers. It's an old brick house and holes in the walls would just screw up the look, value and probably rigidity of the house!
A few little screw-holes can always be filled with a little bit of cement without catching the eye or screwing up the value and rigidity of the wall.
There are plenty of "home cinema" sets out there that use very small satellites containing nothing else than a 3" fullrange driver that have to be mounted against a wall and some of those actually sound pretty good (off course it's not high-end, but it's not like it's totally unacceptable for the spoiled ear), so I guess putting a speaker against a wall shouldn't be all bad after all?
I will not bi-amp the speakers, but I don't see why that would be necessary?
The speakers won't need to play very loud and will be powered by an amplifier more than powerfull enough (at first by my Technics SA-5460: 2x65W RMS, later probably by a Yamaha AX-497: 2x85W RMS) to make the mini-subs move more than enough.
If the Vifa fullrangers tend to play too loud compared to the mini-subs, I can always put a resistor network in to give them a little less power, no?
Off course the top-end dispersion of a fullranger won't be as good as when using a (much smaller in diameter) tweeter, but I don't think that's such a disaster when using a fullranger that is only 3-3.5" in size. It's only for some background music after all and when we want to listen a bit more detailed to the music, we will either be sitting at the "sweet spot" or just go inside and listen to our home-audio speakers.
I don't know what you guys mean by parallel or series filters, since passive crossovers is something I don't have any experience with (my only real experience with audio is car-audio and I'm using active crossovers there and only a capacitor in series with the tweeters to protect them in case something goes wrong), but I was thinking of using:
- a capacitor in series with the fullranger (and maybe a resistor in series and a resistor in parallel with it to match its output with the mini-subwoofer)
- a coil in series with the mini-subwoofer
A box size of 20cm x 20cm x 35cm with a wall-thickness of 2cm brings me to an inside volume of 7.9 liters. I think a compartment of 2.5liters should suffice to make the Vifa TG9 shine, so this means there is 5.4 liters left.
Let's say that's 5 liters net after putting the driver in...
With the TangBand W6-1139 in 5liters sealed, I become a total Q of .75 and a mechanical power handling of about 200Watts without subsonic filters applied!
With the Peerless SLS6.5 in 5 liters sealed, I become a total Q of .61 and a mechanical power handing of about 65Watts without subsonic filters applied.
When putting 65Watts on both woofers (knowing that the TangBand can and will get some more power), I notice the SPL output from 80Hz downwards is pretty much the same on both woofers.
Above 80Hz, the Peerless will give more output, but since low-end extension is more important than max. SPL in this project, I think it's better to choose the driver with the least difference in output between 20Hz and 150ish Hz, and that's the TangBand, which was already my favorite because of the better volume displacement.
Since the TangBand isn't on its limit yet, even with 85W applied and very very deep music, it allows me to use some stuffing and make the virtual enclosure volume a bit bigger to increase the low-end extension even a bit more.
That TangBand driver shows a nice and smooth frequency response untill as high as 900Hz, while the Vifa fullranger with its 3.15mm of x-max should allow me to push it as low as 150-200ish Hz, so this allows me to experiment with the crossoverpoint in a very very wide range of over 2 full octaves!
Isabelle
We are not willing to hack cavities into the outer walls for a couple speakers. It's an old brick house and holes in the walls would just screw up the look, value and probably rigidity of the house!
A few little screw-holes can always be filled with a little bit of cement without catching the eye or screwing up the value and rigidity of the wall.
There are plenty of "home cinema" sets out there that use very small satellites containing nothing else than a 3" fullrange driver that have to be mounted against a wall and some of those actually sound pretty good (off course it's not high-end, but it's not like it's totally unacceptable for the spoiled ear), so I guess putting a speaker against a wall shouldn't be all bad after all?
I will not bi-amp the speakers, but I don't see why that would be necessary?
The speakers won't need to play very loud and will be powered by an amplifier more than powerfull enough (at first by my Technics SA-5460: 2x65W RMS, later probably by a Yamaha AX-497: 2x85W RMS) to make the mini-subs move more than enough.
If the Vifa fullrangers tend to play too loud compared to the mini-subs, I can always put a resistor network in to give them a little less power, no?
Off course the top-end dispersion of a fullranger won't be as good as when using a (much smaller in diameter) tweeter, but I don't think that's such a disaster when using a fullranger that is only 3-3.5" in size. It's only for some background music after all and when we want to listen a bit more detailed to the music, we will either be sitting at the "sweet spot" or just go inside and listen to our home-audio speakers.
I don't know what you guys mean by parallel or series filters, since passive crossovers is something I don't have any experience with (my only real experience with audio is car-audio and I'm using active crossovers there and only a capacitor in series with the tweeters to protect them in case something goes wrong), but I was thinking of using:
- a capacitor in series with the fullranger (and maybe a resistor in series and a resistor in parallel with it to match its output with the mini-subwoofer)
- a coil in series with the mini-subwoofer
A box size of 20cm x 20cm x 35cm with a wall-thickness of 2cm brings me to an inside volume of 7.9 liters. I think a compartment of 2.5liters should suffice to make the Vifa TG9 shine, so this means there is 5.4 liters left.
Let's say that's 5 liters net after putting the driver in...
With the TangBand W6-1139 in 5liters sealed, I become a total Q of .75 and a mechanical power handling of about 200Watts without subsonic filters applied!
With the Peerless SLS6.5 in 5 liters sealed, I become a total Q of .61 and a mechanical power handing of about 65Watts without subsonic filters applied.
When putting 65Watts on both woofers (knowing that the TangBand can and will get some more power), I notice the SPL output from 80Hz downwards is pretty much the same on both woofers.
Above 80Hz, the Peerless will give more output, but since low-end extension is more important than max. SPL in this project, I think it's better to choose the driver with the least difference in output between 20Hz and 150ish Hz, and that's the TangBand, which was already my favorite because of the better volume displacement.
Since the TangBand isn't on its limit yet, even with 85W applied and very very deep music, it allows me to use some stuffing and make the virtual enclosure volume a bit bigger to increase the low-end extension even a bit more.
That TangBand driver shows a nice and smooth frequency response untill as high as 900Hz, while the Vifa fullranger with its 3.15mm of x-max should allow me to push it as low as 150-200ish Hz, so this allows me to experiment with the crossoverpoint in a very very wide range of over 2 full octaves!
Isabelle
Hi,
Many people talk themselves out of BSC in the manner you describe.
the Zaphaudio link I posted earlier implies somewhere for normal
boxes placed near to a wall you will still need around 3dB of BSC.
The TB sub is 83dB/W whilst the Vifa is circa 88dB/W, due to that and likely
BSC issues you'll be looking at a speaker of around 80dB/W which is very
low sensitivity, but because of low sensitivity it will have good bass.
The arrangements I suggested will be around 87dB/W with less bass.
the SLS is more suitable in terms of senstivitity :
http://www.europe-audio.nl/document.asp?document_id=1751&link=datasheets\peerless\830946.pdf
But ideally to run the Vifa without attenuation near wall you want around 90/91dB/W,
and for free space it goes up to 93/94dB/W (a full 10dB above the TB sensitivity)
Which is easiest done by two 84db to 87dB 8 ohm drivers in parallel (+6dB).
Series is a simple re-arrangement of the parallel case you describe :
With 2cm walls your considering a box where the wood takes up
a considerable percentage of the total external volume, making
it slightly bigger all round makes a surprising difference.
rgds, sreten.
Many people talk themselves out of BSC in the manner you describe.
the Zaphaudio link I posted earlier implies somewhere for normal
boxes placed near to a wall you will still need around 3dB of BSC.
The TB sub is 83dB/W whilst the Vifa is circa 88dB/W, due to that and likely
BSC issues you'll be looking at a speaker of around 80dB/W which is very
low sensitivity, but because of low sensitivity it will have good bass.
The arrangements I suggested will be around 87dB/W with less bass.
the SLS is more suitable in terms of senstivitity :
http://www.europe-audio.nl/document.asp?document_id=1751&link=datasheets\peerless\830946.pdf
But ideally to run the Vifa without attenuation near wall you want around 90/91dB/W,
and for free space it goes up to 93/94dB/W (a full 10dB above the TB sensitivity)
Which is easiest done by two 84db to 87dB 8 ohm drivers in parallel (+6dB).
Series is a simple re-arrangement of the parallel case you describe :
An externally hosted image should be here but it was not working when we last tested it.
With 2cm walls your considering a box where the wood takes up
a considerable percentage of the total external volume, making
it slightly bigger all round makes a surprising difference.
rgds, sreten.
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We'll probably buy a good external sound-card with a phantom-powered mic-input and a measuring mic in the near future (we'll be needing that anyways to tune the car-audio install properly and build a pair of good home-audio speakers), so the effects of baffle step, differences in efficiency, peaks or dips in the curve... will be measurable (there's very little to no traffic in our near-future street).
I see where you're going with that series versus parallel filter: Instead of just having a coil in series with the woofer and a cap in series with the fullranger, the coil of the woofer is also in parallel over the fullranger and the cap of the fullranger is also in parallel with the woofer, and to top it off, both drivers are also in series with eachother...
...But what does this with the response of both drivers compared to a parallel crossover?
Won't the Le of the woofer act as a low-pass filter for the fullranger and won't the Re of the woofer bypass the cap, leaving no or less low-cut-off at the fullranger?
And why would this be better than a parallel filter?
I only know parallel filters, so sorry if I'm asking stupid questions...
By the way, you're right about the fact that making the speakers only slightly bigger gives a surprising difference in volume.
I just calculated that a 21cm x 21cm x 35cm box with 2cm walls is already 1 liter bigger (more than 10%!) than a 20cm x 20cm x 35cm box with the same 2cm walls...
Isabelle
I see where you're going with that series versus parallel filter: Instead of just having a coil in series with the woofer and a cap in series with the fullranger, the coil of the woofer is also in parallel over the fullranger and the cap of the fullranger is also in parallel with the woofer, and to top it off, both drivers are also in series with eachother...
...But what does this with the response of both drivers compared to a parallel crossover?
Won't the Le of the woofer act as a low-pass filter for the fullranger and won't the Re of the woofer bypass the cap, leaving no or less low-cut-off at the fullranger?
And why would this be better than a parallel filter?
I only know parallel filters, so sorry if I'm asking stupid questions...
By the way, you're right about the fact that making the speakers only slightly bigger gives a surprising difference in volume.
I just calculated that a 21cm x 21cm x 35cm box with 2cm walls is already 1 liter bigger (more than 10%!) than a 20cm x 20cm x 35cm box with the same 2cm walls...
Isabelle
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Hi,
In series the tweeter current goes through the capacitor and the
bass current goes through the inductor. Look at it and you'll see it.
The main difference is the interaction of the the drivers impedances
with the c/o, especially in this case the sealed resonance of the Vifa.
It will interact with the series c/o in a better way than it does parallel.
rgds, sreten.
In series the tweeter current goes through the capacitor and the
bass current goes through the inductor. Look at it and you'll see it.
The main difference is the interaction of the the drivers impedances
with the c/o, especially in this case the sealed resonance of the Vifa.
It will interact with the series c/o in a better way than it does parallel.
rgds, sreten.
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