@alphabet
If you have an interrest in in compression drivers I would highly recommend you read up on audioasylum's high efficiency board (be warned, nuttah alert, it is not without reason that HE AA members call themselves members of the funny farm, though a lot of the discussion that goes on there is way more reasonable than anything on the rest of the audio asylum). audioheritage.org (or is it lansing heritage) is also a good starting point.
Compression drivers are a charm to work with and present a very rewarding listening experience, to many in the scene the last they seriously invest in unless they start collecting (big old compression drivers are objects of lust for many and can be killer, JBL 2441 and Altecs of the alnico age come to mind). Unfortunately most manufacturers give them a skip becasue they are more expensive (a vifa dome OEM is so cheap, it's not even funny, a decent crossover costs way more to construct) and require a fundamentally different approach to implementing successfully.
There is also a fear of the "horn" signature sound aka honk (caused by reflections at the mouth which show up at regular intevals in the impulse response amongst others) but the current generation of waveguides are actually more benign than dome tweeters if done right.
Appart from being riddiculously efficient (most around the 110dB@1W@1m mark or more depending on horn/waveguide) they are very revealing becasue they reduce the extent to which they interact with the early reverberation of a room. This is the key to the horn-sound (done right) becasue the sound all of a sudden has a stronger direct component. The reverberant field can be shaped to ones liking by choosing the right directivity of the horn, though for the last 15-20 years or so the really good devices are all Constant Directivity (short: CD), evident in the fact that just about all large format studio monitors employ CD waveguides of a sort just about.
The directivity on its own reduces the influence of early reflections on the first 10-20ms in which the human ear perceives most information about the tone of sound. In a damped room the detail is often compared to that of headphones though with a proper live (and preferably diffuse) room one gains back the spaciousness one looses out on with damped rooms in which dome tweeter+ small mid-bass speakers (aka traditional "hi-fi" speakers) perform their best in.
Horns are best used fully active. For a start I would look into a Sound Blaster Live! (preferably Audigy becasue the EMU 10k2 chip has 2x the processing power of the 10k1 but even teh 10k1 is quie useable) and the kX drivers which allow you to a lot of the fancy eq and crossovers as with units like the Behringer Ultradrive DCX 2496. Depending on whether you use a sub or not (handily taken care of with the kX drivers) you would go about choosing a 2-way project.
A measurement setup is also highly recommended, though one can get a set measured and set up by someone with a measurement setup (a 1/3rd octave RTA doesn't cut it anymore thesedays unfortunately). For an investment of around R2k one can sort out a behringer ECM8000, a stand, a pre-amp and the sotware ranges from freeware (the excellent Audua speaker workshop) to exotically expensive.
When testing the waters I would certainly recommend a 10 or 12" paired to a 1" compression driver, quite likely P.Audio (very respectable performance for the cost). Beyma also have some interresting units and 18Sound are also worth a look though at a higher price point.
A good beginner project without spending much on initial outlay would be something along the lines of a P.Audio PA-D34 compression driver (R334 list), a HP-10W (R270 list) mid-bass and some form of waveguide or CD horn. This fairly simple setup would likely surprize many when set up correctly.
A step above that would be a solid 12" mid-bass (Beyma 12LX60, P.Audio C12-300MB, C12-500MB, Winner 12s, etc) on a 1" compression driver like the BM-D440/450 (R424/530 list) and waveguide (or tractrix horn if you have the bent). Note that the larger the enclosure, the more attention you need to put into it to keep the cab resonances in check. Hennie here has a particular penchant for cabinet resonances but there are effective means of reducing those effects to an acceptable degree using a combination of bracing and multiple layers in construction (bitumen panels and/or sand/lead shot construction).
Another option would be a co-ax like the P.Audio BM-8cx (comes in at about a grand a piece and can be gotten to work with as little as a single capacitor for a crossover, though I would recommend a more advanced crossover configuration or even better active.
</ramblings>
Martin out
If you have an interrest in in compression drivers I would highly recommend you read up on audioasylum's high efficiency board (be warned, nuttah alert, it is not without reason that HE AA members call themselves members of the funny farm, though a lot of the discussion that goes on there is way more reasonable than anything on the rest of the audio asylum). audioheritage.org (or is it lansing heritage) is also a good starting point.
Compression drivers are a charm to work with and present a very rewarding listening experience, to many in the scene the last they seriously invest in unless they start collecting (big old compression drivers are objects of lust for many and can be killer, JBL 2441 and Altecs of the alnico age come to mind). Unfortunately most manufacturers give them a skip becasue they are more expensive (a vifa dome OEM is so cheap, it's not even funny, a decent crossover costs way more to construct) and require a fundamentally different approach to implementing successfully.
There is also a fear of the "horn" signature sound aka honk (caused by reflections at the mouth which show up at regular intevals in the impulse response amongst others) but the current generation of waveguides are actually more benign than dome tweeters if done right.
Appart from being riddiculously efficient (most around the 110dB@1W@1m mark or more depending on horn/waveguide) they are very revealing becasue they reduce the extent to which they interact with the early reverberation of a room. This is the key to the horn-sound (done right) becasue the sound all of a sudden has a stronger direct component. The reverberant field can be shaped to ones liking by choosing the right directivity of the horn, though for the last 15-20 years or so the really good devices are all Constant Directivity (short: CD), evident in the fact that just about all large format studio monitors employ CD waveguides of a sort just about.
The directivity on its own reduces the influence of early reflections on the first 10-20ms in which the human ear perceives most information about the tone of sound. In a damped room the detail is often compared to that of headphones though with a proper live (and preferably diffuse) room one gains back the spaciousness one looses out on with damped rooms in which dome tweeter+ small mid-bass speakers (aka traditional "hi-fi" speakers) perform their best in.
Horns are best used fully active. For a start I would look into a Sound Blaster Live! (preferably Audigy becasue the EMU 10k2 chip has 2x the processing power of the 10k1 but even teh 10k1 is quie useable) and the kX drivers which allow you to a lot of the fancy eq and crossovers as with units like the Behringer Ultradrive DCX 2496. Depending on whether you use a sub or not (handily taken care of with the kX drivers) you would go about choosing a 2-way project.
A measurement setup is also highly recommended, though one can get a set measured and set up by someone with a measurement setup (a 1/3rd octave RTA doesn't cut it anymore thesedays unfortunately). For an investment of around R2k one can sort out a behringer ECM8000, a stand, a pre-amp and the sotware ranges from freeware (the excellent Audua speaker workshop) to exotically expensive.
When testing the waters I would certainly recommend a 10 or 12" paired to a 1" compression driver, quite likely P.Audio (very respectable performance for the cost). Beyma also have some interresting units and 18Sound are also worth a look though at a higher price point.
A good beginner project without spending much on initial outlay would be something along the lines of a P.Audio PA-D34 compression driver (R334 list), a HP-10W (R270 list) mid-bass and some form of waveguide or CD horn. This fairly simple setup would likely surprize many when set up correctly.
A step above that would be a solid 12" mid-bass (Beyma 12LX60, P.Audio C12-300MB, C12-500MB, Winner 12s, etc) on a 1" compression driver like the BM-D440/450 (R424/530 list) and waveguide (or tractrix horn if you have the bent). Note that the larger the enclosure, the more attention you need to put into it to keep the cab resonances in check. Hennie here has a particular penchant for cabinet resonances but there are effective means of reducing those effects to an acceptable degree using a combination of bracing and multiple layers in construction (bitumen panels and/or sand/lead shot construction).
Another option would be a co-ax like the P.Audio BM-8cx (comes in at about a grand a piece and can be gotten to work with as little as a single capacitor for a crossover, though I would recommend a more advanced crossover configuration or even better active.
</ramblings>
Martin out
