Anyone made these yet?
I currently have my DX2 in a Voigt style MLTL, but the bass is a bit weedy. My room is 12 foot high, and 20 * 30, so I need a lot of bass. man, the mids & highs are as awesome as you read though. Make Fe166e seem very, very dull.
Before I go down the sub (probably IB or dipole) route, I would like to see if I can get enough from these cabinets.
Thanks,
Graham
I currently have my DX2 in a Voigt style MLTL, but the bass is a bit weedy. My room is 12 foot high, and 20 * 30, so I need a lot of bass. man, the mids & highs are as awesome as you read though. Make Fe166e seem very, very dull.
Before I go down the sub (probably IB or dipole) route, I would like to see if I can get enough from these cabinets.
Thanks,
Graham
These are Lowthers. They really do benefit from a BLH. They have such microscopic Xmax that even the BIB may not work correctly. I would build BLH for sure. I have seen people use them in open baffle, but this seems like a gigantic waste of money. There are speakers out there that sound nearly as good in the upper mids and highs (which is all you will get from OB) that are a fraction of the price. The lowthers really are designed for BLH. Besides, why waste that incredible BL whch translates to extreme tightness of mid bass and bass?
TOm
TOm
The BIB is a BLH. (Of course, if your MLTL is expanding, you could call it a ML-BLH too, if my understanding is correct.) With 12ft ceilings, you'd want to consider an inverted BIB. It would work mouth up, but it wouldn't load as well as it otherwise would (though some clever reflecter might work too). Inverting it would help get the drivers to ear height as well.
pj
pj
12ft ceiling? Normal BIB will be fine -not quite as effective as with a lower one, but I doubt there'd be any problems. Inverting might actually be more of an issue as the driver is already at a decent ear-height -no benefits to be gained in that respect, it's more for drivers with an Fs in the 70Hz regions which are naturally shorter. Bass should be plentiful. As Pj mentions, they are a form of BLH (linear taper, end-loaded) so excursion is a bit less than an MLTL until Fc, where they'll all hit about the same excursion, (assuming the same tuning). A big, chambered BLH with hyperbolic expansion, tuned like a BIB to 1/2 wavelength would be my choice if you wanted something a little more advanced.
Scottmoose said:
I don't know the current thinking on Lowther dims, but my issue is with the driver being too high, not too low as is the problem with the little ones (70hz fs). It looks to me like the driver will end up somewhere in the mid 40"'s off the floor, which is high for me. Fliped and on a little stand, and you could end up at the ideal (for me in most chairs) 36". This is precisely what I'm contemplating with mine.
Also, it seems to me that in practicle terms (all enclosures aren't tuned to the same Fc), the BIB does a better job of controling excursion than most anything else. Most MLTL's and more common BLH designs don't load the driver so low, so you end up with a bunch of uncontrolled excursion below Fc. The BIB's (for the lower Fs drivers) control excursion to nearly the bottom of the musical spectrum (only ht frequencies are below it, in my case.) No flopping around at 40-50hz here, in the range many other fullrange enclosures are unloaded.
pj
pjanda1 said:
Well, not really. You may in certain designs get some horn action but no it is not a horn. Transmission lines work by amplifying the 1/4 wave of the FS of the driver in a resonant tube. A horn actually takes the output from the rear of the driver and amplifies the entire spectrum down to whatever the tuning of your horn is. (very simplified terms) The way you stop a horn from amplfying the entire signal is through the use of a coupling chamber which in effect is a mechanical crossover that cuts the sound off above a predetermined frequency. Now, it is possible and quite likely that you will have some TL action in a horn, but in most cases not enough to take note of. Ideally if there is some, you want to have TL action and horn action working together but it is hard to get right and tends to muddy up the bass a bit. Remember, The reason a horn works is the flare constant mixed with length, throat and mouth size. In a TL you will get differing results with a more or less tapered design but what matters is not nessessarily the taper but the length and cross section of the tube as well as the driver placement. As always, if anyone sees error in my statement, I am always happy to take correction. I hopethis helps in your journey.
Tom
pj -Yes, I've noticed that all enclosures aren't tuned to the same freqency.
For a regular BIB, you'd be looking at a driver about 39in off the floor, fractionally off-vertical axis for most of us, which is beneficial in flattening the rising response of the drivers. Unless of course higher SPLs for the treble are desired, as some people wish.
Generally the BIB is a little better than an MLTL in controlling driver excursion, but actually not that much, until they're properly positioned in a corner, which pushes it down considerably. Because it's tuned so low, they can often push the point of maximum driver excursion 1 octave above Fc into a slightly less critical zone. Every little helps, though I think people tend to set too much stock by this.
Tom -actually the BIBs are technically a branch of horn. All TQWTs or expanding lines can be considered as such, at a very basic level. They're just a specific type; end-loaded, with linear taper. A horn does not automatically have to have a filter chamber -it was Olson who introduced that in the widest sense in his 1937 patent. Look at all those gramophone horns, or the traditional megaphones. It's the usual grey area really as to where one type starts and another leaves off. I tend to consider all expanding lines from the horn perspective when designing.
For a regular BIB, you'd be looking at a driver about 39in off the floor, fractionally off-vertical axis for most of us, which is beneficial in flattening the rising response of the drivers. Unless of course higher SPLs for the treble are desired, as some people wish.
Generally the BIB is a little better than an MLTL in controlling driver excursion, but actually not that much, until they're properly positioned in a corner, which pushes it down considerably. Because it's tuned so low, they can often push the point of maximum driver excursion 1 octave above Fc into a slightly less critical zone. Every little helps, though I think people tend to set too much stock by this.
Tom -actually the BIBs are technically a branch of horn. All TQWTs or expanding lines can be considered as such, at a very basic level. They're just a specific type; end-loaded, with linear taper. A horn does not automatically have to have a filter chamber -it was Olson who introduced that in the widest sense in his 1937 patent. Look at all those gramophone horns, or the traditional megaphones. It's the usual grey area really as to where one type starts and another leaves off. I tend to consider all expanding lines from the horn perspective when designing.
Scottmoose said:
Scott, I have always been under the impression that for a horn to be a true horn it had to have a flare constant (as in curve)? Hmm. That's good to know! Thanks!
I love posting here. People generally are so good at replying without pretense. And Scott has been in all cases for me the most helpful of anyone. Listen to this guy, he knows what he is talking about! Hehe. Sorry for the ego stroking Scott, just wanted to extend my thanks.
Tom
You're welcome -if I can help with anything, I try to (even if my sense of humour occasionally gets the better of me, for which I apologise 
). But I don't pretend to be an expert though -I leave that to my betters -in particular, GM, Martin, Dave, & Ron. Those guys are the Masters & I owe them a lot -what little I know I learned from them, along with our much-missed friend Terry Cain, who got me into the BIB thing in the first place a few years back.
In a sense a horn does indeed have to have a flare constant -the BIBs expansion is continued by the room, which forms a part of the speaker-system / cabinet. I'd probably put it around the catenoid region, but that's fudged -depends on where you stand the things!
). But I don't pretend to be an expert though -I leave that to my betters -in particular, GM, Martin, Dave, & Ron. Those guys are the Masters & I owe them a lot -what little I know I learned from them, along with our much-missed friend Terry Cain, who got me into the BIB thing in the first place a few years back. In a sense a horn does indeed have to have a flare constant -the BIBs expansion is continued by the room, which forms a part of the speaker-system / cabinet. I'd probably put it around the catenoid region, but that's fudged -depends on where you stand the things!
Greets!
Horns don't have to have a flare constant, it just has to expand enough for 1/2 WL action to occur, changing the pipe from a 1/4 WL resonator (only odd order harmonics) to a 1/2 WL resonator (both even and odd orders) with a 1/4 WL fundamental: http://hyperphysics.phy-astr.gsu.edu/hbase/waves/opecol.html#c1
Where folks get confused is that they look at a compression loaded horn and conclude that this system is the horn because it's what the pros call them, when actually it's a 4th order bandpass speaker with a tacked on acoustically large expanding vent designed to ideally load it at the inverse of its response, so we start with a severely under-damped, limited BW speaker and through acoustic transformation convert it into a severely over-damped one of much wider gain BW.
GM
Horns don't have to have a flare constant, it just has to expand enough for 1/2 WL action to occur, changing the pipe from a 1/4 WL resonator (only odd order harmonics) to a 1/2 WL resonator (both even and odd orders) with a 1/4 WL fundamental: http://hyperphysics.phy-astr.gsu.edu/hbase/waves/opecol.html#c1
Where folks get confused is that they look at a compression loaded horn and conclude that this system is the horn because it's what the pros call them, when actually it's a 4th order bandpass speaker with a tacked on acoustically large expanding vent designed to ideally load it at the inverse of its response, so we start with a severely under-damped, limited BW speaker and through acoustic transformation convert it into a severely over-damped one of much wider gain BW.
GM
Greets!
You're welcome! Just 'horn basics for the masses' published in various DIY books such as where I learned it, Cohen's '56 'HI-FI Loudspeakers and Enclosures'. Lacking this basic understanding, I imagine that compression horn design must seem like a form of black magic even with a simming program since there's so many variables to juggle.
GM
You're welcome! Just 'horn basics for the masses' published in various DIY books such as where I learned it, Cohen's '56 'HI-FI Loudspeakers and Enclosures'. Lacking this basic understanding, I imagine that compression horn design must seem like a form of black magic even with a simming program since there's so many variables to juggle.
GM
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