First let me submit the disclaimer that I'm a full range newbie. I recently bought a pair of W8-1808s and put together a somewhat odd, but I think creative, semi open baffle design. Basically I unhooked the compression drivers in my Klipsch KG 5.5s, turned them sideways to point the woofers to the side walls and present the larger side surfaces to the listener, put together a pair of open baffles made from MDF stair treads and mounted the TBs in those and stood them next to the Klipsch speakers so that the front baffle of the "stair tread" is an extension of the side of the Klipsch (I'll try to post pics sometime). Then I ran my Golden Tube Audio amp direct to the Tang Bands, ran a solid state Crown to the Klipsch, and ran my Audible Illusions preamp through an Ashly active crossover and sent the mids/highs to the tube/Tang Bands and the bass to the Crown/Klipsch. This currently is fed by my Rega Planet CD (my turntable is in the middle of another upgrade project). The system isn't optimized yet - the Tang Band speakers aren't broken in, and I need to bypass the Klipsch crossovers and wire those woofers directly to the amp. I plan to do a few more mods (mostly adding some bracing) to the Klipschs while I'm in there. I played with the crossover a little, but most listening was with the crossover somewhere in the 150 to 200 Hz range.
Overall, I'm pretty impressed. Well recorded CDs sound amazing. There is a bit too much "zing" in the treble, but that improves if I move away a few feet (my normal listening spot is about 10 feet from the speakers), so I think some adjustments in speaker position may solve that to some degree. I'm hoping the mids will bloom a bit and the treble will tame down a tad as they break in. I'm not ready to add any electronics to "fix" that just yet. There is a slight tendency for a loss of realism with loud passages using multiple instruments, but overall definitely the best sound I've had from my home system yet. There is a definite change in balance as you move from the listening area consistent with the loss of the "beaming" treble; on "edgy" material its an improvement.
I have little idea how these compare with Lowthers or other high dollar speakers, but I'm pretty happy with them.
Overall, I'm pretty impressed. Well recorded CDs sound amazing. There is a bit too much "zing" in the treble, but that improves if I move away a few feet (my normal listening spot is about 10 feet from the speakers), so I think some adjustments in speaker position may solve that to some degree. I'm hoping the mids will bloom a bit and the treble will tame down a tad as they break in. I'm not ready to add any electronics to "fix" that just yet. There is a slight tendency for a loss of realism with loud passages using multiple instruments, but overall definitely the best sound I've had from my home system yet. There is a definite change in balance as you move from the listening area consistent with the loss of the "beaming" treble; on "edgy" material its an improvement.
I have little idea how these compare with Lowthers or other high dollar speakers, but I'm pretty happy with them.
>>> I ran my Golden Tube Audio amp direct to the Tang Bands, ran a solid state Crown to the Klipsch, and ran my Audible Illusions preamp through an Ashly active crossover and sent the mids/highs to the tube/Tang Bands and the bass to the Crown/Klipsch. This currently is fed by my Rega Planet...
You have some excellent and interesting gear! You just need to play around more and figure out what you want. I think you have all the right ingredients but see you in an experimental mode to determine which type of speakers you like best. This is probably the perfect forum to discuss your situation.
I like the 1808 a lot and think it's maybe the best full range driver i've heard to date. But it's not perfect... just better than many others. It does have a treble zing at first and it is more prominent when closer to it. But i noticed this went away after a few hours and has not come back. It works great in open baffle AND bass reflex. I may do a BR cab for it soon and compare to my OB setup to see how the driver behaves differently in both types of cabs. It's not really an OB speaker but just happens to work well this way. I think once you dial in the correct bass from your helper woofers (whatever they end up being) you will find you have balanced sound from top to bottom. I also have a super tweeter on my 1808 and think it helps fill out the top octaves adding dynamics, punch and realism.
Godzilla
You have some excellent and interesting gear! You just need to play around more and figure out what you want. I think you have all the right ingredients but see you in an experimental mode to determine which type of speakers you like best. This is probably the perfect forum to discuss your situation.
I like the 1808 a lot and think it's maybe the best full range driver i've heard to date. But it's not perfect... just better than many others. It does have a treble zing at first and it is more prominent when closer to it. But i noticed this went away after a few hours and has not come back. It works great in open baffle AND bass reflex. I may do a BR cab for it soon and compare to my OB setup to see how the driver behaves differently in both types of cabs. It's not really an OB speaker but just happens to work well this way. I think once you dial in the correct bass from your helper woofers (whatever they end up being) you will find you have balanced sound from top to bottom. I also have a super tweeter on my 1808 and think it helps fill out the top octaves adding dynamics, punch and realism.
Godzilla
My experience with the W8-1808
This driver has the ability to make you look and feel like a genius! It can produce such amazing sound, with so little effort. Yet, it can secretly drive you mad, if you let it. It can reveal SO MUCH, that you could spend countless hours on inane tweaks and experiments. For me it's fun...
I'm very curious about your remark; that's it's not an OB driver, but happens when to work as one. I can hear the inner Scooby Doo in my head now: "HaRuh...?!?" Could you explain your idea of what constitutes an OB driver? Because OB is, as OB does; if it works, it is, when it comes to OB. In fact, it works flawlessly in this arrangement.
This driver has the ability to make you look and feel like a genius! It can produce such amazing sound, with so little effort. Yet, it can secretly drive you mad, if you let it. It can reveal SO MUCH, that you could spend countless hours on inane tweaks and experiments. For me it's fun...
I'm very curious about your remark; that's it's not an OB driver, but happens when to work as one. I can hear the inner Scooby Doo in my head now: "HaRuh...?!?" Could you explain your idea of what constitutes an OB driver? Because OB is, as OB does; if it works, it is, when it comes to OB. In fact, it works flawlessly in this arrangement.
Qts is far too low for this driver to be used OB with no LF reinforcement.
Its possible to apply some EQ to boost the low-end for open baffle use, but this isn't advisable - excursion increases distortion, and you could hit serious issues if you drop a needle too hard - think coil smashing into backplate.
Chris
Its possible to apply some EQ to boost the low-end for open baffle use, but this isn't advisable - excursion increases distortion, and you could hit serious issues if you drop a needle too hard - think coil smashing into backplate.
Chris
Ah! I think possibly you're muddling the line between the terms OB, fullrange, and woofer. A woofer would need a higher Qts to be considered an OB. Likewise, the W8-1808 would not be considered to operate truly as a fullrange in OB, due to the roll off. But name any driver that will. I think maybe the terms FR and OB are synonymous in your mind. But, really, most OBs are not fullrange. The ability to operate "free-air" involves many parameters in addition to Qts, which has mostly to do with bass response.
If you put the 1808 in a big enough baffle, you'll find it produces as much bass as any 8" driver that is not limited to woofer-only duty. And I'd love to see another driver that can reach any lower and as high, with gorgeous midrange, all while being completely unfiltered, nor modified.
In short, OB is about more than Qts, and anyone willing to be rational, knows a FR in OB is going to need some help in the basement.
If you put the 1808 in a big enough baffle, you'll find it produces as much bass as any 8" driver that is not limited to woofer-only duty. And I'd love to see another driver that can reach any lower and as high, with gorgeous midrange, all while being completely unfiltered, nor modified.
In short, OB is about more than Qts, and anyone willing to be rational, knows a FR in OB is going to need some help in the basement.
>>> It's not really an OB speaker but just happens to work well this way.
Old post. I love this driver. It's great on OB and after a year or so of experimenting with drivers on open baffle I agree, any driver could work as long as it has bass support. I no longer use a tweeter with the 1808 either.
Old post. I love this driver. It's great on OB and after a year or so of experimenting with drivers on open baffle I agree, any driver could work as long as it has bass support. I no longer use a tweeter with the 1808 either.
I'm definitely not muddling up those terms. All drivers considered suitable for open baffle use have a Qts high enough that they'll have a useful amount of LF extension, without throwing 12dB+ of EQ at it.
Anything not-immediately-suitable for full-range OB use will need some bass support. Sure, you can still use them on an open baffle, but not without help.
The Visaton B200 would be a useful example here - this driver has a Qts of 0.75, and would therefore be somewhere near ideal to throw on a big-ish baffle and call it good. Bass extension would be enough for most small-scale music. This has been done many times by DIYers.
The TB driver mentioned above will be rolling off somewhere around 150Hz, regardless of how big you make the baffle: it has a very low Qts, and therefore requires reinforcement from a cabinet to get anything useful below that.
A narrow OB will put an even higher cutoff on things, but you'll still get a 12dB/octave drop below the mass corner.
Chris
Anything not-immediately-suitable for full-range OB use will need some bass support. Sure, you can still use them on an open baffle, but not without help.
The Visaton B200 would be a useful example here - this driver has a Qts of 0.75, and would therefore be somewhere near ideal to throw on a big-ish baffle and call it good. Bass extension would be enough for most small-scale music. This has been done many times by DIYers.
The TB driver mentioned above will be rolling off somewhere around 150Hz, regardless of how big you make the baffle: it has a very low Qts, and therefore requires reinforcement from a cabinet to get anything useful below that.
A narrow OB will put an even higher cutoff on things, but you'll still get a 12dB/octave drop below the mass corner.
Chris
I figure regardless of open baffle size, a driver on it will roll off below its mass corner (Fs/qts). So the 1808 (on even an infinite baffle) will roll off below 100hz.
I had qts .45 with Fs around 43hz 12". Even on a 2' deep open baffle (the phy one), there wasn't much bass.
But running it as a full range crossed 100-200hz, it should work great so long as the dispersion works for you.
The 1808 seems a little bright because it is a little hot in the 1.5khz - 3.5khz range, where I'd prefer a 5db dip, not +5db.
And listening off axis won't help too much as it gets more directive as you go above 2khz.
Nice driver, not cheap, and still needs eq to my ears.
Norman
I had qts .45 with Fs around 43hz 12". Even on a 2' deep open baffle (the phy one), there wasn't much bass.
But running it as a full range crossed 100-200hz, it should work great so long as the dispersion works for you.
The 1808 seems a little bright because it is a little hot in the 1.5khz - 3.5khz range, where I'd prefer a 5db dip, not +5db.
And listening off axis won't help too much as it gets more directive as you go above 2khz.
Nice driver, not cheap, and still needs eq to my ears.
Norman
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Respectfully, Chris, you're completely blurring the lines here. I agree that there's absolutely nothing wrong with the belief that an OB driver should operate respectably in full range. I, myself, have similar sentiments and believe it goes well with all the things we love to tack onto the goals of open baffle alignments. Such things include: minimalism, purity, minimized phase shift, lack of filtering, getting closer to the music (without a strict insistence on traditional "audiophile" rules, which often contradict musical enjoyment), etc. These are the things that ride along with the open baffles of today. YET... They are not married to it and are the designer's prerogative. In other words, you can take 25 different drivers and cut 25 holes in a big board and you'll have a huge, disgraceful mess (probably). But, it's an open baffle, all the same! The ones handling the lower registers will usually do a lot better if they have a very high Qts. But the drivers operating in the higher ranges STILL need to operate well in an open baffle. You hint that any driver works in OB above the bass. That's not true.
You state:
"All drivers considered suitable for open baffle use have a Qts high enough that they'll have a useful amount of LF extension, without throwing 12dB+ of EQ at it."
A truer statement would be:
"MOST drivers considered suitable for FULL RANGE open baffle use have a Qts high enough..."
-or-
"All drivers THAT *I* consider suitable for open baffle use..."
It's like saying all Ferraris are red. The more you talk, the clearer I hear this. You obviously think that all OB drivers must be essentially full range or woofers. In your mind, the definition of an OB driver centers around bass performance. We all have preferences and if that's how you choose to see the world, that's a fine thing. However, there's a lot more needed of a driver, in order to do well in open baffle, than simple bass extension. In fact, if bass extension is your primary target, you're definitely barking up the wrong audio tree with OB! OB will get you many wonderful things and bass extension is possible... But it's the most difficult thing to achieve with this arrangement. It becomes nearly impossible to achieve true full range performance from a single driver, if a lack of deep bass is a deal breaker for you. So, any real bass, is going to need "helpers."
Here's a mind blower for you, as well, Qts isn't set in stone. The 1808 can easily be configured to have a Qts of around .65 to .7, which is in the ballpark of where you consider OB drivers to be. I think you'd ruin the fine attributes of this driver by doing so, and we both agree that it needs a bit of help in the bass. Yet, I believe you'll never find a driver more worthy of the moniker of "OB," if you open your mind and see that there's a whole frequency spectrum and ALL OF IT is affected by being in an open baffle.
You state:
"All drivers considered suitable for open baffle use have a Qts high enough that they'll have a useful amount of LF extension, without throwing 12dB+ of EQ at it."
A truer statement would be:
"MOST drivers considered suitable for FULL RANGE open baffle use have a Qts high enough..."
-or-
"All drivers THAT *I* consider suitable for open baffle use..."
It's like saying all Ferraris are red. The more you talk, the clearer I hear this. You obviously think that all OB drivers must be essentially full range or woofers. In your mind, the definition of an OB driver centers around bass performance. We all have preferences and if that's how you choose to see the world, that's a fine thing. However, there's a lot more needed of a driver, in order to do well in open baffle, than simple bass extension. In fact, if bass extension is your primary target, you're definitely barking up the wrong audio tree with OB! OB will get you many wonderful things and bass extension is possible... But it's the most difficult thing to achieve with this arrangement. It becomes nearly impossible to achieve true full range performance from a single driver, if a lack of deep bass is a deal breaker for you. So, any real bass, is going to need "helpers."
Here's a mind blower for you, as well, Qts isn't set in stone. The 1808 can easily be configured to have a Qts of around .65 to .7, which is in the ballpark of where you consider OB drivers to be. I think you'd ruin the fine attributes of this driver by doing so, and we both agree that it needs a bit of help in the bass. Yet, I believe you'll never find a driver more worthy of the moniker of "OB," if you open your mind and see that there's a whole frequency spectrum and ALL OF IT is affected by being in an open baffle.
Norman, here's some things that might help you.
1. Your design has an apparent baffle step (rise in output, due to acoustic factors) in the range you don't like. Try something different, after reading up on baffle step effect. You'll likely want something very different from a flat panel.
2. OBs need room to breathe! You're causing an early cancellation by having it so close to the wall AND corner. Remember that OBs operate the opposite of other speakers in this regard, so the corner eats your bass, instead of reinforcing it. Alternatively, you could try placing it all the way in the corner, sealed to the wall, with a top panel and plenty damping inside. You'd no longer have an open baffle... But what you show in the picture is hardly acting as an open baffle anyway.
3. If you're up for experimentation, try reading the work of Mr. King (OB guru) and try "cupping" the air behind the driver. This can greatly increase Qts and lower your corner to as low as maybe 60 Hz. There are serious trade offs, though. Still, it's a great thing to try and you might really like what it does for you.
4. If the dispersion of the W8-1808 doesn't work for you, that's understandable... but there's really nothing much better out there; maybe fullrange isn't for you. A good alternative is to add a tweeter crossed gentle and way high. I recommend the mini-AMT with a 1uf cap in series (about 10 kHz... But don't be fooled; the slope is gentle and there's plenty output down to 5 kHz). There's no need for any filter on the 1808 up high, but if you find comb filtering takes hold, a simple series arrangement with the cap (the opposite of traditional parallel wiring) will help.
I'm available to answer any questions, just let me know!
1. Your design has an apparent baffle step (rise in output, due to acoustic factors) in the range you don't like. Try something different, after reading up on baffle step effect. You'll likely want something very different from a flat panel.
2. OBs need room to breathe! You're causing an early cancellation by having it so close to the wall AND corner. Remember that OBs operate the opposite of other speakers in this regard, so the corner eats your bass, instead of reinforcing it. Alternatively, you could try placing it all the way in the corner, sealed to the wall, with a top panel and plenty damping inside. You'd no longer have an open baffle... But what you show in the picture is hardly acting as an open baffle anyway.
3. If you're up for experimentation, try reading the work of Mr. King (OB guru) and try "cupping" the air behind the driver. This can greatly increase Qts and lower your corner to as low as maybe 60 Hz. There are serious trade offs, though. Still, it's a great thing to try and you might really like what it does for you.
4. If the dispersion of the W8-1808 doesn't work for you, that's understandable... but there's really nothing much better out there; maybe fullrange isn't for you. A good alternative is to add a tweeter crossed gentle and way high. I recommend the mini-AMT with a 1uf cap in series (about 10 kHz... But don't be fooled; the slope is gentle and there's plenty output down to 5 kHz). There's no need for any filter on the 1808 up high, but if you find comb filtering takes hold, a simple series arrangement with the cap (the opposite of traditional parallel wiring) will help.
I'm available to answer any questions, just let me know!
Of course it centres around bass performance. With a cutoff of around 200Hz at 12dB/octave (combination of mass corner and dipole rolloff), a considerable portion of music is lost - IIRC, the most energy in music is in the 300Hz range.
What other ways of categorising an OB driver are there?
I'd argue you can use pretty much anything from a few hundred Hz upwards, so there's no need to specify. I'm not saying that all 3" drivers are equal, just that, given a 12+" bass driver and some attention to the crossover, they'd perform just fine on an OB.
Could you expand a bit on your point #4 above? - I'm in the dark about why changing the wiring arrangement might fix comb filtering/lobing.
Chris
What other ways of categorising an OB driver are there?
I'd argue you can use pretty much anything from a few hundred Hz upwards, so there's no need to specify. I'm not saying that all 3" drivers are equal, just that, given a 12+" bass driver and some attention to the crossover, they'd perform just fine on an OB.
Could you expand a bit on your point #4 above? - I'm in the dark about why changing the wiring arrangement might fix comb filtering/lobing.
Chris
Chris, this is an interesting conversation! I say that because, you and I seem to think a lot alike and I agree with what you're trying to say. But, what experience has taught me, is that people come to these forums as a way of educating themselves. When terms are not clearly defined, it makes a longer and harder path for them. For folks like you and I, we're just discussing things and we understand each other pretty well. I just want to make sure that anyone newer has the advantage of knowing exactly what we mean, when we use these terms.
As for your question about wiring arrangements... In trying for brevity, I knew I wasn't being clear enough and that's why I'm happy to answer questions. Drawing a picture would make things easier... But words will suffice.
The "traditional" crossover arrangement is wired in parallel and considered better for "voltage-drive" amplifiers (but the other works too... especially in simpler circuits like I describe). Each driver is wired straight to the amplifier (in parallel) and has it's own filter. As such, the filter components have a lesser effect on the paralleled drivers (the ones they aren't hooked directly to).
In a series crossover, the drivers are wired in a chain (in series) and the filter components are wired as one unit. It looks a lot like you took a parallel crossover and turned it on its side; what was wired in series, is now parallel and vice versa. Since it becomes a single filtration unit (with each driver tapping into the piece it needs), the effect of any given component, is spread to the whole speaker. So, a single cap can act as a mild filter for both the FR and the tweeter.
As you probably know, when you have two sources producing in the same range, they need to be within a certain distance (center to center, in both the X/Y and Z axis) in order to couple and avoid comb filtering and lobing artifacts. The physical size and function of these two drivers makes this impractical, if not impossible, and likely undesirable anyway. The two drivers would need to have their acoustic centers within 1" of each other. Good luck with that...
The fact is, it might not even be an issue for his setup. But, if he found it was, he could experiment with different positions and arrangements that minimize this effect, such as greatly separating the drivers (8"... a foot... three feet...), angling them in different directions, using waveguides... and so on. This would be in effort to take advantage of the fact that the theory above is virtually nonexistent in reality; the two drivers will not launch at exactly the same speed/moment. As well, by increasing the gap, one might increase the effect enough to create an opposite effect in the net result.
-or-
Simply cut out the overlap with an inductor on the W8-1808. I would hate to see that, though, because this driver is so pure and awesome without anything extra in the path!
If he has the right part laying around, he could try it. Or, he could use a series arrangement with only the capacitor and try it that way.
Ultimately, you want to go with the crossover that works best with your particular amplifier. Not to oversimplify things, but usually tube amplifiers operate under the current-drive principle (due to having a transformered output) and SS, as voltage sources. As such, you will probably want to use the correct and corresponding type of crossover arrangement for the final edition. However, experimentation, if done carefully, can give you an idea of where you're headed, without having to buy extra components, until you know exactly what you need. This is one way of doing that.
Descriptions:
A typical two way, with first order filters on both drivers, as a parallel:
- the FR has its negative terminal connected to the negative binding post for the speaker, and it's positive terminal connected to the positive post, with an inductor in line with it.
- the tweeter is wired the same, with exception of a capacitor connecting the positive terminal to the positive post, instead of an inductor.
- So, both driver's negative terminals are wired to the negative post and the same with the positive terminals to the positive post, but with each have its own filter component.
The same filtration/crossover, wired in series:
- the FR has its negative terminal connected to the negative post, as above.
- the tweeter has its positive terminal connected to the positive post.
- the positive terminal of the FR is connected to the negative terminal of the tweeter.
- the inductor is wired across the terminals of the tweeter and the capacitor is wired across the terminals to the FR (the exact opposite wiring of a parallel crossover).
The crossovers I originally proposed would be just like above, but you leave out the inductor. So that you are effectively not filtering the FR when used as a parallel crossover and vice versa as a series. A WORD OF CAUTION: keep the volume low when you're not filtering the tweeter (using the cap as a series crossover element). Tweeters DON'T like low frequencies!
By doing this as an experiment, you are trading potential HF combing, for combing at a lower frequency and a smaller degree.
Of course you are always welcome to do it "right" and use an active crossover, feeding two amplifiers. Even if you plan on using passive components in your speakers, having these tools is great for future designs, as a means of quicker diagnosis and experimentation.
Is all that clear as mud now?
As for your question about wiring arrangements... In trying for brevity, I knew I wasn't being clear enough and that's why I'm happy to answer questions. Drawing a picture would make things easier... But words will suffice.
The "traditional" crossover arrangement is wired in parallel and considered better for "voltage-drive" amplifiers (but the other works too... especially in simpler circuits like I describe). Each driver is wired straight to the amplifier (in parallel) and has it's own filter. As such, the filter components have a lesser effect on the paralleled drivers (the ones they aren't hooked directly to).
In a series crossover, the drivers are wired in a chain (in series) and the filter components are wired as one unit. It looks a lot like you took a parallel crossover and turned it on its side; what was wired in series, is now parallel and vice versa. Since it becomes a single filtration unit (with each driver tapping into the piece it needs), the effect of any given component, is spread to the whole speaker. So, a single cap can act as a mild filter for both the FR and the tweeter.
As you probably know, when you have two sources producing in the same range, they need to be within a certain distance (center to center, in both the X/Y and Z axis) in order to couple and avoid comb filtering and lobing artifacts. The physical size and function of these two drivers makes this impractical, if not impossible, and likely undesirable anyway. The two drivers would need to have their acoustic centers within 1" of each other. Good luck with that...
The fact is, it might not even be an issue for his setup. But, if he found it was, he could experiment with different positions and arrangements that minimize this effect, such as greatly separating the drivers (8"... a foot... three feet...), angling them in different directions, using waveguides... and so on. This would be in effort to take advantage of the fact that the theory above is virtually nonexistent in reality; the two drivers will not launch at exactly the same speed/moment. As well, by increasing the gap, one might increase the effect enough to create an opposite effect in the net result.
-or-
Simply cut out the overlap with an inductor on the W8-1808. I would hate to see that, though, because this driver is so pure and awesome without anything extra in the path!
If he has the right part laying around, he could try it. Or, he could use a series arrangement with only the capacitor and try it that way.
Ultimately, you want to go with the crossover that works best with your particular amplifier. Not to oversimplify things, but usually tube amplifiers operate under the current-drive principle (due to having a transformered output) and SS, as voltage sources. As such, you will probably want to use the correct and corresponding type of crossover arrangement for the final edition. However, experimentation, if done carefully, can give you an idea of where you're headed, without having to buy extra components, until you know exactly what you need. This is one way of doing that.
Descriptions:
A typical two way, with first order filters on both drivers, as a parallel:
- the FR has its negative terminal connected to the negative binding post for the speaker, and it's positive terminal connected to the positive post, with an inductor in line with it.
- the tweeter is wired the same, with exception of a capacitor connecting the positive terminal to the positive post, instead of an inductor.
- So, both driver's negative terminals are wired to the negative post and the same with the positive terminals to the positive post, but with each have its own filter component.
The same filtration/crossover, wired in series:
- the FR has its negative terminal connected to the negative post, as above.
- the tweeter has its positive terminal connected to the positive post.
- the positive terminal of the FR is connected to the negative terminal of the tweeter.
- the inductor is wired across the terminals of the tweeter and the capacitor is wired across the terminals to the FR (the exact opposite wiring of a parallel crossover).
The crossovers I originally proposed would be just like above, but you leave out the inductor. So that you are effectively not filtering the FR when used as a parallel crossover and vice versa as a series. A WORD OF CAUTION: keep the volume low when you're not filtering the tweeter (using the cap as a series crossover element). Tweeters DON'T like low frequencies!
By doing this as an experiment, you are trading potential HF combing, for combing at a lower frequency and a smaller degree.
Of course you are always welcome to do it "right" and use an active crossover, feeding two amplifiers. Even if you plan on using passive components in your speakers, having these tools is great for future designs, as a means of quicker diagnosis and experimentation.
Is all that clear as mud now?
I agree that just about any driver that is smooth above 300Hz or so can be used with a helper woofer nicely in an OB. Take for example a pro audio midrange driver that I used in OB - the PRV 5MR450NDY, crossed at 340Hz in a 12in wide OB sounds wonderful. 95dB sensitivity and reach to 15kHz with a balanced sound. This was probably never meant to be an OB driver.
http://www.diyaudio.com/forums/full-range/259293-prv-5mr450-ndy-fast-applications.html
I have used this same concept with other drivers and it works quite well. 3FE25, 3FE22, TC9FD, 6MDN44, RS100-4, just high pass around 250Hz to 350Hz and they work well as OB. In the case of the 6MDN44, it needs to have a low pass at 5kHz and a tweeter. Btw, the ESS Heil AMT dipole tweeter is one of the best sounding tweeters I have heard and it inherently dipole so perfect for OB.
Only if you need the OB to get bass below 200Hz without EQ do you need high Qts.
http://www.diyaudio.com/forums/full-range/259293-prv-5mr450-ndy-fast-applications.html
I have used this same concept with other drivers and it works quite well. 3FE25, 3FE22, TC9FD, 6MDN44, RS100-4, just high pass around 250Hz to 350Hz and they work well as OB. In the case of the 6MDN44, it needs to have a low pass at 5kHz and a tweeter. Btw, the ESS Heil AMT dipole tweeter is one of the best sounding tweeters I have heard and it inherently dipole so perfect for OB.
Only if you need the OB to get bass below 200Hz without EQ do you need high Qts.
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Agreed xrk971... and I love my OB!
Unfortunately, there's a lot of waste with OB design compared to back horns as we add overall output. This could simply be that as DIYers we are using what we can get our hands on. I stick everything on OB these days just for a listen. Without the variables of bass optimization there's a lot less effort needed to get great results. Anything smooth above 250Hz works for me.
Unfortunately, there's a lot of waste with OB design compared to back horns as we add overall output. This could simply be that as DIYers we are using what we can get our hands on. I stick everything on OB these days just for a listen. Without the variables of bass optimization there's a lot less effort needed to get great results. Anything smooth above 250Hz works for me.
May I ask how you all calculated the coil and resistor to calm the top end? At present I have a 2.4mh and 15ohm. In my room that works pretty well. Is there a better calculation? I also have a notch: 52.82mfd, 0.68mh and 8ohms.
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