Scott L wrote:

IMO  A 60Hz attempt is too low and a 120Hz attempt too high. This is a difficult task, that of properly integrating horn loaded mid-bass with D.R subs. What type and slope crossover are you using ? I'm hoping you are going active here ? How much air can your sub woofer section move ? You simply MUST be able to move prodigious amounts of air at the very low frequencies. Keep in mind, that in order for these two to integrate, you must maintain a linear range of response, to at LEAST, an octave past either side of the crossover point. And that, is almost impossible with a horn loaded mid-bass. The key word being "almost" but not impossible. It's very difficult. To use, say, a 100Hz x-over point, your mid bass horn should reach an F3 somewhere close to 50Hz, and your subs should be linear to 200Hz. Most subs BEG to rise in response as frequency ascends. Ideally, this is dealt with in the design, but a last ditch effort would be to add EQ. after the crossover. Yes, please do show pictures !

Romy the Cat wrote:

Scott L wrote: IMO  A 60Hz attempt is too low and a 120Hz attempt too high. This is a difficult task, that of properly integrating horn loaded mid-bass with D.R subs. What type and slope crossover are you using ? I'm hoping you are going active here ? How much air can your sub woofer section move ? You simply MUST be able to move prodigious amounts of air at the very low frequencies. Keep in mind, that in order for these two to integrate, you must maintain a linear range of response, to at LEAST, an octave past either side of the crossover point. And that, is almost impossible with a horn loaded mid-bass. The key word being "almost" but not impossible. It's very difficult. To use, say, a 100Hz x-over point, your mid bass horn should reach an F3 somewhere close to 50Hz, and your subs should be linear to 200Hz. Most subs BEG to rise in response as frequency ascends. Ideally, this is dealt with in the design, but a last ditch effort would be to add EQ. after the crossover. Yes, please do show pictures ! Scott, I think you a bit overly complicate the task of integration of mid/upper bass with LF. The key mistake you make (in my view) is semantic. You call LF section as subwoofer that immediately bring in imagination an industry boom box sitting in a corner trying to fill the room with lower octaves. Yes, the integration of those type solutions is very complicated and in my mind it still never work properly. Subwoofers work OK with a pair of mini-monitors and total cost of $500. If you went to extend to build multichannel time-aligned horn installation then you are way out of subwoofers rhetoric and you need to talk/thin about a truly potent LF acoustic system. I personally feel that line-arrays with cylindrical waves, good drivers and long walls work spectacularly well with horns and they are very easy to integrate. So, it is all about a proper chose of topology. Whatever it might be it must not be subwoofers. Subwoofers as a category is consumer-level audio element and the concept should not be used along withany  high-endish objectives.

Scott L wrote:

the last time I checked, you were using 6each @ 10 inch low frequency drivers per side. That's "getting there" but still not enough to produce an acoustical watt. (which horns CAN do).

Romy the Cat wrote:

Scott L wrote:  the last time I checked, you were using 6each @ 10 inch low frequency drivers per side. That's "getting there" but still not enough to produce an acoustical watt. (which horns CAN do).     I am not sure what you mean. At the times when I used 6 driver line-arrays for sub 100Hz region it was integrated with 115Hz upper bass horn and I assure you that both integration and overall sound were very fine. I do not think that it would work in larger or non-sealed room however but it worked very well in there, I think it was ~300 sq feet. So, I do not know what you mean saying “not enough to produce an acoustical watt”.  In that room ANY design of midbass horn would be a disasters.

Gargoyle wrote:

Romy the Cat wrote:  Scott L wrote:  the last time I checked, you were using 6each @ 10 inch low frequency drivers per side. That's "getting there" but still not enough to produce an acoustical watt. (which horns CAN do).     I am not sure what you mean. At the times when I used 6 driver line-arrays for sub 100Hz region it was integrated with 115Hz upper bass horn and I assure you that both integration and overall sound were very fine. I do not think that it would work in larger or non-sealed room however but it worked very well in there, I think it was ~300 sq feet. So, I do not know what you mean saying “not enough to produce an acoustical watt”.  In that room ANY design of midbass horn would be a disasters.  My guess is was referring to the pressure levels at the surface of the woofer(s) compared to that of a horn. The sound pressure of a direct radiator has to be much high to achieve a certain SPL at the same distance of a lower pressure horn. It is a phrase more commonly used in pro-sound circles. Typical direct radiator types are only capable of producing ~3 acoustical watts for every 100 electrical watts input. One acoustical watt is ~107 db from an OMNIdirectional source. I haven't done them math to see how your array compares, but I can surmise that Scott is suggesting that your particular implementation in that room was not up to the task of orchestra, which is considered to be ~1 acoustic watt in power. Probably OK for rock though.

Gargoyle wrote:

My guess is was referring to the pressure levels at the surface of the woofer(s) compared to that of a horn. The sound pressure of a direct radiator has to be much high to achieve a certain SPL at the same distance of a lower pressure horn. It is a phrase more commonly used in pro-sound circles. Typical direct radiator types are only capable of producing ~3 acoustical watts for every 100 electrical watts input. One acoustical watt is ~107 db from an OMNIdirectional source. I haven't done them math to see how your array compares, but I can surmise that Scott is suggesting that your particular implementation in that room was not up to the task of orchestra, which is considered to be ~1 acoustic watt in power. Probably OK for rock though.

Scott L wrote:

Romy's bass driver array is actually a very good approach. 6 x10's per side is actually enough to produce an acoustical watt at the upper part of the range they cover, but not down to the subterranean depths of an orchestra's hall ambiance. I did not realize his former room in the basement apartment was as small as it evidently was. What about now, though ?    Actually, the point of my post was illustrate the acoustical needs for proper integration of the two types of systems. Also let me add here, I feel for domestic settings, this approach makes the most sense from a practical viewpoint.

Romy wrote:

My question is: why in this picture the concept of Acoustic Power or Acoustical Watt can advance anything? I am not being sarcastic, I just truly do not know where to use it.

Romy the Cat wrote:

So, Gargoyle, from what you says this concept of “acoustic watt” is used to predict the necessary power/gain of amplification needed for a drive an acoustic system in a given room. I feel that the acoustic wattage is very odd way to do it.

Romy the Cat wrote:

BTW, the acoustical resistance of air is NOT nonlinear.