I guess it's time for me to resurrect this thread.
After having less time than I would have liked last summer to build speakers combined with the lack of direction that I had in this design I am still left without any good speakers for my AV system. After more study and thought I have given up on the baffle step approach with the double woofers for several reasons.
I then thought to combine the two Silverflute drivers and use a double mid bass approach since I needed about a 3 db sensitivity increase to match well with the Vifa woofer and tweeter. I liked this idea and came up with this conceptual model for the cabinet based on a slightly modified shape of a very well regarded Sony ES ss-m9 floor standing speaker.
In this design the 5.25 and 6.5 inch Silverflute drivers are driven by an identical mid/bass range signal. Unfortunately this puts the acoustic center of the mid/bass a little farther from the tweeter than I would like and since this is meant to be a project done for a modest outlay of cash I wanted to consider a simpler crossover design.
After having less time than I would have liked last summer to build speakers combined with the lack of direction that I had in this design I am still left without any good speakers for my AV system. After more study and thought I have given up on the baffle step approach with the double woofers for several reasons.
I then thought to combine the two Silverflute drivers and use a double mid bass approach since I needed about a 3 db sensitivity increase to match well with the Vifa woofer and tweeter. I liked this idea and came up with this conceptual model for the cabinet based on a slightly modified shape of a very well regarded Sony ES ss-m9 floor standing speaker.
In this design the 5.25 and 6.5 inch Silverflute drivers are driven by an identical mid/bass range signal. Unfortunately this puts the acoustic center of the mid/bass a little farther from the tweeter than I would like and since this is meant to be a project done for a modest outlay of cash I wanted to consider a simpler crossover design.
Attachments
Although I like the above design I am now leaning toward something else. Having been influenced by Lynn Olsen's thread "Beyond the Arial" I have somewhat began thinking about more sensitive designs. And because this is to be primarily the fronts for a home theater system my feeling is that dynamics should take a higher place that absolute resolution so long as the resolution is still good.
So now I am back to a different topology that I really like. The system is simpler but a little larger. It sacrifices some wide range dispersion in the upper midrange for increased cone area and sensitivity. So hopefully it will be very dynamic with less compression. Since the ear is very sensitive in the upper midrange area it might even be better to have less total energy bouncing around the room in the 1800-4000 Hz range so the larger than usual mid/bass may not pose too much of a problem.
My approach is to use the Vifa P21W as the mid bass driver instead of the woofer. I have heard this driver playing full range hooked directly to a good amp and was amazed at it's mid range quality and it has about the smoothest roll off for an 8 inch driver that I have seen.
So here is a higher quality render of the concept design. I have a Vifa D27 linen dome tweeter that I like and will use with the P21W. The woofer will be a 12 inch Part express or something. Most likely aperiodic loading for the both the bass and mid/bass cabinet.
I am thinking seriously about some high end composite construction techniques for the upper head unit that I have been milling about in my mind. I think I have come up with a way to build a better cabinet than Wilson or Rockport but it will be labor intensive.
So we are back to the quazi Watt/Puppy kind of cabinet shape but with some variation that I like.
So now I am back to a different topology that I really like. The system is simpler but a little larger. It sacrifices some wide range dispersion in the upper midrange for increased cone area and sensitivity. So hopefully it will be very dynamic with less compression. Since the ear is very sensitive in the upper midrange area it might even be better to have less total energy bouncing around the room in the 1800-4000 Hz range so the larger than usual mid/bass may not pose too much of a problem.
My approach is to use the Vifa P21W as the mid bass driver instead of the woofer. I have heard this driver playing full range hooked directly to a good amp and was amazed at it's mid range quality and it has about the smoothest roll off for an 8 inch driver that I have seen.
So here is a higher quality render of the concept design. I have a Vifa D27 linen dome tweeter that I like and will use with the P21W. The woofer will be a 12 inch Part express or something. Most likely aperiodic loading for the both the bass and mid/bass cabinet.
I am thinking seriously about some high end composite construction techniques for the upper head unit that I have been milling about in my mind. I think I have come up with a way to build a better cabinet than Wilson or Rockport but it will be labor intensive.
So we are back to the quazi Watt/Puppy kind of cabinet shape but with some variation that I like.
Attachments
Hi,
http://www.deadwaxcafe.com/vzone/david/david.htm
See the approach for BSC allowing full mid driver sensitivity to be used.
IMO your suggested arrangement with near floor bass driver would
need partial BSC on the mid with some lower frequency reinforcement.
/sreten.
http://www.deadwaxcafe.com/vzone/david/david.htm
See the approach for BSC allowing full mid driver sensitivity to be used.
IMO your suggested arrangement with near floor bass driver would
need partial BSC on the mid with some lower frequency reinforcement.
/sreten.sreten said:Hi,
IMO your suggested arrangement with near floor bass driver would
need partial BSC on the mid with some lower frequency reinforcement.
Sreten,
here is another option. Making a four way or a 3.5 way by moving the 8 inch woofer down to the top of the lower cabinet. I think I have found a SEAS 6-7 inch mid/bass driver that is sensitive enough in the 700-3000 Hz zone to work with these other drivers and keep the system in the 90 -91 db sensitivity area. The 12 inch looks like it's going to be a Dayton series 2 woofer.
This setup gives me two woofers that are spaced a different distance from the floor. I think I can run the upper woofer all the way down and the 12 inch supplementing it below 80 Hz or so. With the lower cabinet volumes I will be going aperiodic which is what I was thinking anyway as I am going to be favoring bass pitch quality over extension. I already have a separate subwoofer so I would prefer these speakers to have really good quality bass in the 50-100 Hz range.
I would like to work this up with an acoustic reality crossover if possible. If not I will go with the standard 12 db parallel topology.
Attachments
marchel said:
Marcel,
Since I already have some drivers that I want to use I am trying to integrate them into my design goals. I'm finding that higher sensitivity non pro drivers are harder to find now days.
I want the increased cone area of the 12 inch woofer although I could go for a 10 inch in that application. But since these are going to be the fronts in a home theater and there is often lots of bass effects in the fronts I would like more cone radiating area. If I was only going to listen to music with these speakers I would have different design goals.
Hezz said:
Hi,
FWIW I think it is completely over the top for use with a seperate
subwoofer unless that is some form of very low bass monster.
Mixed woofers 12"/15" and 10"/12" have been done by Focal
and if you get the parameters right, can share the same airspace.
But I'd say twin identical woofers is far more straightforward.
Proper bass reflex alignments (i.e. tuned low) do not affect the
upper bass quality, though I accept sealed overdamped can match
rooms well. Aperoidic loading is much misunderstood and essentially
pointless IMO for most drivers. It works best when it must be used.
Not much wrong with the original Watt/Puppy arrangement.
/sreten.sreten said:
Hi,
FWIW I think it is completely over the top for use with a seperate
subwoofer unless that is some form of very low bass monster.
Mixed woofers 12"/15" and 10"/12" have been done by Focal
and if you get the parameters right, can share the same airspace.
But I'd say twin identical woofers is far more straightforward.
Proper bass reflex alignments (i.e. tuned low) do not affect the
upper bass quality, though I accept sealed overdamped can match
rooms well. Aperoidic loading is much misunderstood and essentially
pointless IMO for most drivers. It works best when it must be used.
Not much wrong with the original Watt/Puppy arrangement.
The subwoofer is only used with movie soundtracks since my AV receiver does not seem to have the option of mixing it with anything other than DD or DTS. So when I listen to music I don't use it. It is a 12 inch sub in a 4 cubic foot enclosure tuned low. With room gain it is flat to around 17-18 Hz. It is good sounding to me for a subwoofer and is a BR design but it lacks the pitch definition of my old aperiodic 3 ways in the bass. It's also only used below about 70-80 Hz with the current small cheap front speakers. With new fronts the balance may need to be adjusted.
So what I want is a very substantial bass foundation in the front speakers that can add some extra semi deep juice. I'm only going to have about a 1.5 - 1.7 cubic foot space for the lower woofer so a 10 inch model is not out of the question. Perhaps with a 10 inch lower woofer I can use BR tuning for that and get some lower response. However, I have reason to believe that an aperiodic design does not load the room with such an unnatural pressure wave because of some of the self balancing effect of the acoustic flow control vent which does not emphasis a narrow range of frequencies.
In fact, I know that there is not much design information on aperiodic designs, but I cannot think of the aperiodic loading as anything but an acoustic flow control vent. To me, just as the contained air in the enclosure can be viewed as a spring which is undamped in relation to the cone, the resistive vent can be viewed as a shock absorber or spring dampener just like in a hydraulic system. It seems to me that it should be modeled as such but using gas laws of course instead of liquids. But since it is easy to tune by ear I don't know if it is worth the effort.
For some reason, possibly because this is a AV speaker first and foremost I am leaning on the goal of extra cone area for less dynamic compression. The dynamics are of paramount importance in this speaker. More than resolution or sound staging or imaging.
Here is another option that is back to a cabinet design similar to the first at the beginning of this thread.
This cabinet shape is a little easier to built.
Proposed drivers are:
Tweeter, Vifa D27
Midrange, Aurum Cantus 7 inch AC-180F1
Woofer 1, Vifa P21W
Woofer 2, Dayton series 2 10 inch
This cabinet shape is a little easier to built.
Proposed drivers are:
Tweeter, Vifa D27
Midrange, Aurum Cantus 7 inch AC-180F1
Woofer 1, Vifa P21W
Woofer 2, Dayton series 2 10 inch
Attachments
tinitus said:
"Proposed drivers"...........what does that mean exactly
I suppose that such a special arrangement with 2 different woofers is tested ?
It means that these are the drivers that at this point I am planning on using. I already have the two Vifa drivers. I have chosen the other drivers based on sensitivity matching and for the mid range a cone material similar to the upper woofer which I hope gives a good timbre match.
Sreten,
The two woofers in the lower enclosure will be in seperate enclosures so I don't anticipate that thier mechanical and acoustic variances will be too much of a problem to deal with. If they were in the same space I would think that would be a totally different issue.
I have done some outstanding sounding aperiodics but mine are different in that it is not an attempt to stuff a high qts speaker in a small box. With mine I use a speaker of around .32-.38 qts, in a volume that would be .6 -.7 Q in sealed box. Then I tune the resistive vent by ear. I love the relaxed timbre quality of this loading. It sounds more natural to me. It sounds more like an infinite baffle loading which I like.
The two woofers in the lower enclosure will be in seperate enclosures so I don't anticipate that thier mechanical and acoustic variances will be too much of a problem to deal with. If they were in the same space I would think that would be a totally different issue.
I have done some outstanding sounding aperiodics but mine are different in that it is not an attempt to stuff a high qts speaker in a small box. With mine I use a speaker of around .32-.38 qts, in a volume that would be .6 -.7 Q in sealed box. Then I tune the resistive vent by ear. I love the relaxed timbre quality of this loading. It sounds more natural to me. It sounds more like an infinite baffle loading which I like.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.