noviygera wrote:

Romy, I have somewhat different possibilities than you are seeing. My system is physically higher than most because my listening position is at standing height or sitting in a high stool. I have used this litening height for a few years and grew to appreciate for a number of reasons (worth separate discussion). One of which is increased space under the midrange horn and less interaction from floor.  So I gain about 20" of height below mid. In fact I measure easy 46" from floor to mid horn edge. Another contraversial thing I use is DSP crossover. It is not perfect but I have DELAY in my arsenal! So I can use full length horn. This, at least covers TWO of your rightly noted concerns. Does this open options to continue discussion further? If so I am happy to further formulate my requirements. 1. Gracefully integration with midrange horn at 250-300hz with 6db/oct crossover and absolutely no allowed EQ. 2. Staright rectangular or five sided vs folded: this is something I do not know.

noviygera wrote:

Also you say: "In reality the driver is the key"So let me ask for advice on suitable driver(s). This be my next step. Need I select a size? Or driver with certain spec? For example lets say driver "x" is good for this range and has been tried and proven. What is your recommendation on driver for this range? Or better way to look at this, HOW do you recommend to select the driver? For example, you use Fane Studio 8 in a different range with different horn but maybe this driver will also work in my application? No? ok, but what qualifies the driver? Or is it purely coincidental match? Is it the case that all 400watt treated paper pro drivers should not be even considered, etc.

noviygera wrote:

You provided very good starting points on the driver selection and I am also corresponding with a gentleman that may help me with actual horn design. I have found a couple of drivers that seem to work based on your guidelines. They are pro sound 10" to 12" with Fs around 50-55hz. Is it the case that driver size should be no more than certain diameter to sound decent in 60 to 300hz range? Such as, 15" being too large I need to look at no more than 12"? It looks like current hifi drivers are out question and anything remotely suitable is going to be PA. ps. Correction: I just noticed that Fostex 8" full range drivers meet those specs and have very low power handling (maybe too low).

noviygera wrote:

Romy, You make very, very good points now I am re-evaluating this all-in-one horn concept. I do know one thing that I learned from my current system. Midbass horn that rolls off below 120 hz and integrated with sub is not good. I have struggled with this format for 2 years with no successful solution and this led me to explore a more expanded midbass channel. The transition from 120hz horn to direct radiator subs is not possible to be seamless without significant loss of focused sound.

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.