That's Alpair 10.2!
I think I'll try OB without the bass speaker first as this seems by far the easiest option, and will allow me to listen to it, and decide what I'm missing (if anything). And later I can modify the baffle or build a new one and stick those extra woofers in. Experience is the best teacher, isn't it
So assuming a single Alpair 10.2 driver and relaxing bass requirements somewhat, is there anything in particular that I need to keep in mind while making a baffle for it? I like the baffle idea from Racket Science's link, but I would like to make it slightly bigger and give it a slightly more "rounded" look - are there any potential pitfalls in doing this?
(a little off-topic) I know it involved some voodoo at the time, but I still think the idea has potential.
Mount a driver on a baffle, then put another driver below + behind it, in a large sealed cabinet. Cross the rearward driver over at ~200Hz, 2nd order low pass.
The effect is that the low frequency waves from the back of the driver are mostly eliminated by the back driver, so you get bass output from the front of the driver.
Down side is you need double the drivers.
(/off topic)
I'd second/third/fourth(etc) the idea of an active crossover. There's a lot of amplifiers on ebay (I got a 120w/ch studio amp for £70 delivered). Eminence Alpha 15As seem to be popular, they're maybe £80/pr if you look around. Certainly cheaper than replacing a pair of Alpairs every time you turn it up.
Chris
Mount a driver on a baffle, then put another driver below + behind it, in a large sealed cabinet. Cross the rearward driver over at ~200Hz, 2nd order low pass.
The effect is that the low frequency waves from the back of the driver are mostly eliminated by the back driver, so you get bass output from the front of the driver.
Down side is you need double the drivers.
(/off topic)
I'd second/third/fourth(etc) the idea of an active crossover. There's a lot of amplifiers on ebay (I got a 120w/ch studio amp for £70 delivered). Eminence Alpha 15As seem to be popular, they're maybe £80/pr if you look around. Certainly cheaper than replacing a pair of Alpairs every time you turn it up.
Chris
Prepare...worms are coming out
Don't want to scare you, put please stick to some proved design, with proven drivers, baffle sizes and crossover points/slopes. Alternatively, you may elect to spend next 2+years tweaking and tweaking. In the end, maybe you'll be happy...
p.s. There's no bass without 15"
Ok, now a bit more serious:
1. Don't build the Visaton NoBox design- it's not worth it.
2. Sooner or later, you will need a 15" bass driver.
3. Active is easier to set up and better sounding IMHO than passive, so you will not go wrong if you get another amp +active crossover.
My OB: -50x120 cm plain baffle
-Eminence Beta 15/bass
-Visaton B200/ highs
-Biamped, DIY active crossover
-LP 80 Hz 12 db/oct, Q=0.5 + passive T-bass circuit
-HP 350 Hz 12 db/oct Q=0.5 +notch
1. Don't build the Visaton NoBox design- it's not worth it.
2. Sooner or later, you will need a 15" bass driver.
3. Active is easier to set up and better sounding IMHO than passive, so you will not go wrong if you get another amp +active crossover.
My OB: -50x120 cm plain baffle
-Eminence Beta 15/bass
-Visaton B200/ highs
-Biamped, DIY active crossover
-LP 80 Hz 12 db/oct, Q=0.5 + passive T-bass circuit
-HP 350 Hz 12 db/oct Q=0.5 +notch
Nelson,
The other popular OB design is to have a narrow baffle and use the driver below the dipole hump. The response falls linearly at 6 dB/octave so EQ is applied to get a flat SPL response. This usually requires three or four drivers, active crossover and filters, multiple amps, and a stepped or tapered baffle so that each driver is operating in a narrow baffle region. Linkwitz's Orion or John K's Note speakers are good examples. Different trade-offs and design goals.
Martin
That's Alpair 10.2!
I think I'll try OB without the bass speaker first as this seems by far the easiest option, and will allow me to listen to it, and decide what I'm missing (if anything). And later I can modify the baffle or build a new one and stick those extra woofers in. Experience is the best teacher, isn't it
So assuming a single Alpair 10.2 driver and relaxing bass requirements somewhat, is there anything in particular that I need to keep in mind while making a baffle for it? I like the baffle idea from Racket Science's link, but I would like to make it slightly bigger and give it a slightly more "rounded" look - are there any potential pitfalls in doing this?
Your low frequency output will start to roll-off at about 200 Hz. Don't expect to get much bass below 100 Hz. As Jim said, be careful with the volume so you don't trash the driver.
Martin
PLLXO is an interesting idea, but I use all sorts of unusual arrangements to feed my amp: my DAC has a passive output stage fed into a passive volume control for amp. Between the TDA1543 output pin and amp's input pin there is only a resistor (I/V), a capacitor (DC filter), and a potentiometer (volume control). All this (amazingly enough ) works rather brilliantly, but I'm afraid inserting additional stuff would mess things up. - btw. now you have an idea how far I took the "simplicity principle" lol
Active crossovers are merely shifting the problem (signal degradation) from one place to another... And to be honest, I would rather use a passive crossover - at least I could build it with exotic parts and it wouldn't generally be that bad (although difficult/expensive to experiment with). While the Behringer crossover mentioned earlier, is plainly rubbish and goes completely against my principles, with its multiple opamps, complex circuits and whatnots. I don't have a single opamp or tube in my entire system.
Anyway, it's not that I'm against all crossovers, I'm only against a crossover on the fullrange. I see it as a waste of potential to use a crossover on a driver capable of running with no crossovers. I could perhaps live with a "single cap crossover" - but the cap would have to be a fairly massive to allow the fullrange to still operate in the upper bass regions, which means I couldn't use a film cap... (I could parallel two or three, but this would create a new problem, inter-capacitor resonances).
I appreciate that feeding a smallish driver with LF bass and no loading is asking for trouble, but the Alpair 10.2 has 8.5mm xmax - I would say that's reasonable room for some fairly low bass, even with its rather small cone area... As long as I keep the loudness reasonable, of course.
And please, I don't want to sound like I'm asking for advice and then not accepting it. It's not that. I'm just the type of person that doesn't give up easily, and I believe that with almost any problem, no matter how big, there is a way above, through or around it. It may be unexpected, unconventional or simply expensive - but it exists
) works rather brilliantly, but I'm afraid inserting additional stuff would mess things up. - btw. now you have an idea how far I took the "simplicity principle" lol Active crossovers are merely shifting the problem (signal degradation) from one place to another... And to be honest, I would rather use a passive crossover - at least I could build it with exotic parts and it wouldn't generally be that bad (although difficult/expensive to experiment with). While the Behringer crossover mentioned earlier, is plainly rubbish and goes completely against my principles, with its multiple opamps, complex circuits and whatnots. I don't have a single opamp or tube in my entire system.
Anyway, it's not that I'm against all crossovers, I'm only against a crossover on the fullrange. I see it as a waste of potential to use a crossover on a driver capable of running with no crossovers. I could perhaps live with a "single cap crossover" - but the cap would have to be a fairly massive to allow the fullrange to still operate in the upper bass regions, which means I couldn't use a film cap... (I could parallel two or three, but this would create a new problem, inter-capacitor resonances).
I appreciate that feeding a smallish driver with LF bass and no loading is asking for trouble, but the Alpair 10.2 has 8.5mm xmax - I would say that's reasonable room for some fairly low bass, even with its rather small cone area... As long as I keep the loudness reasonable, of course.
And please, I don't want to sound like I'm asking for advice and then not accepting it. It's not that. I'm just the type of person that doesn't give up easily, and I believe that with almost any problem, no matter how big, there is a way above, through or around it. It may be unexpected, unconventional or simply expensive - but it exists
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All good advice so far. As to the statement "there is no bass without 15", I would amend that to "there is no loud bass without 15". At low volumes, many of the full range speakers will put out reasonable lows down to around 100 Hz, which is where your baffle will start to give out at preventing cancellation (if its an "old fashioned" wide baffle like mine) anyway. Finally, many are using a skinnier baffle and depending on active EQ and helper woofers for the bass, and in a skinny baffle bass is difficult to generate. The other factor that makes it appear there is little bass is the rising response of many of these speakers, which accentuates the treble. I find that a well designed Zobel balances this out nicely. Some feel that a 4" full-range is the right size to be able to cover the spectrum well while reducing "beaming" of the treble, but you may want to consider a larger (6 to 8") speaker to give you some increased efficiency and power handling unless you always listen at a pretty low volume if you're going with only one crossoverless speaker per channel.
Having said that, there are at least 3 other people posting in this thread that, at least in this field, know orders of magnitude more about this stuff than I do.
Having said that, there are at least 3 other people posting in this thread that, at least in this field, know orders of magnitude more about this stuff than I do.
Prepare...worms are coming out
Don't want to scare you, put please stick to some proved design, with proven drivers, baffle sizes and crossover points/slopes. Alternatively, you may elect to spend next 2+years tweaking and tweaking. In the end, maybe you'll be happy...
p.s. There's no bass without 15"
Well, if there is an existing open-baffle, full-range, crossover-less loudspeaker design, I would love to try it
With or without 15" And all of them agree that crossovers are necessary... That gives me an idea about how difficult a problem I presented...
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If you look at where the devil lives (the details), an active crossover is generally superior, not simply shifting the degradation. Here's another couple of links for you:
Active Vs. Passive Crossovers
Passive Crossover Network Design
Based on what's been said so far, I'd advise you to pick the fullrange speaker that looks good to you, and put it on a cheap plywood, old school 33 inch wide baffle and give it a listen. Then tweak from there.
Active Vs. Passive Crossovers
Passive Crossover Network Design
Based on what's been said so far, I'd advise you to pick the fullrange speaker that looks good to you, and put it on a cheap plywood, old school 33 inch wide baffle and give it a listen. Then tweak from there.
Dear uncle_leon
Like you I am new to OB, and did a lot of reading before making my decision. I am VERY happy with my what I decided and it is a very cheap way to get into OB. For me, simplicity is a must, and how is a full range a full range if it has a helper and a crossover? Mine sound great and are based on this simple design: HERE. The bass goes plenty low to 60hz and I am only using a single driver
Thats my $0.02
Like you I am new to OB, and did a lot of reading before making my decision. I am VERY happy with my what I decided and it is a very cheap way to get into OB. For me, simplicity is a must, and how is a full range a full range if it has a helper and a crossover? Mine sound great and are based on this simple design: HERE. The bass goes plenty low to 60hz and I am only using a single driver
Thats my $0.02
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Joined 2009
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Dear uncle_leon
Like you I am new to OB, and did a lot of reading before making my decision. I am VERY happy with my what I decided and it is a very cheap way to get into OB. For me, simplicity is a must, and how is a full range a full range if it has a helper and a crossover? Mine sound great and are based on this simple design: HERE. The bass goes plenty low to 60hz and I am only using a single driver
2
I also made my first and only OB using a larger cone with small whizzer. The pictures are here: http://www.diyaudio.com/forums/full-range/174632-apollo-ob.html
I never connected up the high frequency horns or cross over and the whole lot is now with my friend. What I remember of it, the large cone hardly moved at all - and this may be the key to making an OB with a single driver - using a large cone allows for some bass without overly large cone movements. The bass I heard wasn't very strong but it did reach down.
I would suggest not on an open baffle run FR. I'd consider it with a Visaton B200 on a big baffle (which really requires a room larger than yours), but the 5 1/4" A10.2 would easily be destroyed with no loading on the backside.
The Alpair is a wonderful driver, and i can heartily recommend it, but put it into a proper box.
dave
Well, if there is an existing open-baffle, full-range, crossover-less loudspeaker design, I would love to try it
Vixaron B200 in a big baffle works fine ... kist too big for my room, but that room has to accomodate more than me and the hifi. The B200s do need to be modified to meet their full potential (a pair is on my bench being prepared for the UK as we speak)
dave
You could make an open backed box. You can add a 15" or 2 x 12" later (active crossover or do it passively with bass boost). It would be 24" wide x 48" tall and 10" deep with foam wrapping driver on inside baffle. That way, you get your full range driver flat to below 200hz (assuming Fs/qts < 200hz).
I'm doing a monstro (sr) with the 1808 (60" tall, 3 panels, center 12" wide, left 15" wide, right 19" wide, driver 37" from floor).
Norman
I'm doing a monstro (sr) with the 1808 (60" tall, 3 panels, center 12" wide, left 15" wide, right 19" wide, driver 37" from floor).
Norman
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