steve71 said:
That is not my experience with tapped horns. Since the woofer is still the source for the sound and the pressurization of the tapped horn is almost instantaneous, it doesn’t appear to suffer from the time delay issues like front loaded bass horns in my experience. However, what I did find is you have to phase align the tapped horn to what ever your mid-bass source is. Since I use mid-bass horns, I had to space the tapped horn along an arc to get them in phase. Once I did this, everything clicked in and I had no time delay issues.
Rgs, JLH
JLH said:
Interesting JLH... I have the ability add or remove the delay in real time and the timing is better when I take into account the 350cm of horn - L23. It adds about 10ms of delay IIRC.
I'm not sure what you mean when you say, "Since the woofer is still the source for the sound and the pressurization of the tapped horn is almost instantaneous"
The sound still has to travel though the horn before it gets to your ears. There's really no way around that, or am I missing something
It probably depends on how far away the mouth is from the front of the driver, for the differing opinions of time delay issues.
Any chance the 200Hz peak you speak of is a cabinet panel resonance? Does it sound like 200Hz when you kick the box, or is it well braced? Maybe could it be a resonance happening in the short space between the driver and the mouth?
Any chance the 200Hz peak you speak of is a cabinet panel resonance? Does it sound like 200Hz when you kick the box, or is it well braced? Maybe could it be a resonance happening in the short space between the driver and the mouth?
PikeFish, my sub is pretty well braced, and even if it wasn't I couldn't imagine panel resonances attributing to the huge peaks and valleys above 90hz. Maybe I miss understand how a TH works, but isn't the hash just the front and rear output of the cone's output coming in and out of phase?
The HR data & FR for my sub is posted on page 95 of the tapped horn thread along with some pics of the internal bracing.
http://www.diyaudio.com/forums/showthread.php?postid=1629349
BTW I love your sig line. Told it to the wife and we had a good laugh. We miss the Aussie sense of humor over here in the US.
The HR data & FR for my sub is posted on page 95 of the tapped horn thread along with some pics of the internal bracing.
http://www.diyaudio.com/forums/showthread.php?postid=1629349
BTW I love your sig line. Told it to the wife and we had a good laugh. We miss the Aussie sense of humor over here in the US.
Well braced indeed, that's certainly not the culprit.
I'll mention now my current practical experience with the TH is nil, so I probably won't get to the bottom of this peak, and wouldn't want to fill this thread with an investigation.
Although, and I don't know if it's acoustically possible for this to be an issue, but if it is this is a good thread for it, it does look like the path length from driver to mouth could be about 0.43m, the quarter wave resonance length for 200Hz afaik.
Could a pile of stuffing at the panel adjacent to the mouth help?
I'll mention now my current practical experience with the TH is nil, so I probably won't get to the bottom of this peak, and wouldn't want to fill this thread with an investigation.
Although, and I don't know if it's acoustically possible for this to be an issue, but if it is this is a good thread for it, it does look like the path length from driver to mouth could be about 0.43m, the quarter wave resonance length for 200Hz afaik.
Could a pile of stuffing at the panel adjacent to the mouth help?
I might experiment with some stuffing down the track, but for the most part though it's a non issue as I'm running the sub though a Behringer Ultra Cruve Pro. It's got 3 PEQ's to deal with the first three peaks and I've created a 16db shelf for everything in the bandpass with the EQ. I still need to build a HP filter though.
I only mention it as others have said it's not an issue. Not to say I'm right and they're wrong my any means. Just trying to relate my experience with the TH I built.
I only mention it as others have said it's not an issue. Not to say I'm right and they're wrong my any means. Just trying to relate my experience with the TH I built.
Haven't posted in a while, some of the posts seem to be a slight De-Rail.
That doesn't seem to fall in line with what Tom Danley Has stated nor What I have found. My DTS like TH has a driver with a 40Hz FS and has a knee around 21HZ.
The MTX Thunder T9515-44 is used in toms TH-50 it performs to arround 22Hz and has an FS of 34Hz. He's also used that driver in the Matterhorn which is supposed to perform to 16Hz.
I'm guessing the driver needs a little more help controlling its excursion for tapped horns.
I think there is probably an close to ideal percentage of length. Tom Danley again mentioned in one of his posts that indeed the horn path has to be longer than the 1/4 wave of the low cut.
HF drivers typically have higher compression ratios, I think the material the cone is made of somewhat determines the amount of compression the cone can handle. I'm not sure how conventional horn compression ration rules differ from, what works good/better/best for tapped horns.
HR doesn't give you anything. You have to enter segment area and length manually. Unless there is a new version of HornResp. You can play with the variables, but I don't want to waste my time farting with the TH tool except to try and optimize an already close horn.
Take a look at the DTS-20. I think its safe to say that the opening (mouth??) is smaller than the area of the chamber behind it. The horn path expands an when it reaches its exit the opening is a contraction.
Again I don't think HornResp gives you anything. It simply crunches the numbers you put into it.
It would appear that the Th-28 contracts near the mouth.
It doesn't seem unreasonable to play with a cigar like path, it seems to do some interesting things. I'm sure that there could be a reason to have different expansions and contractions depending on the design goal.
Antone-
FlipC said:
That doesn't seem to fall in line with what Tom Danley Has stated nor What I have found. My DTS like TH has a driver with a 40Hz FS and has a knee around 21HZ.
The MTX Thunder T9515-44 is used in toms TH-50 it performs to arround 22Hz and has an FS of 34Hz. He's also used that driver in the Matterhorn which is supposed to perform to 16Hz.
FlipC said:
I'm guessing the driver needs a little more help controlling its excursion for tapped horns.
FlipC said:
I think there is probably an close to ideal percentage of length. Tom Danley again mentioned in one of his posts that indeed the horn path has to be longer than the 1/4 wave of the low cut.
FlipC said:
HF drivers typically have higher compression ratios, I think the material the cone is made of somewhat determines the amount of compression the cone can handle. I'm not sure how conventional horn compression ration rules differ from, what works good/better/best for tapped horns.
FlipC said:
HR doesn't give you anything. You have to enter segment area and length manually. Unless there is a new version of HornResp. You can play with the variables, but I don't want to waste my time farting with the TH tool except to try and optimize an already close horn.
FlipC said:
Take a look at the DTS-20. I think its safe to say that the opening (mouth??) is smaller than the area of the chamber behind it. The horn path expands an when it reaches its exit the opening is a contraction.
FlipC said:
Again I don't think HornResp gives you anything. It simply crunches the numbers you put into it.
It would appear that the Th-28 contracts near the mouth.
It doesn't seem unreasonable to play with a cigar like path, it seems to do some interesting things. I'm sure that there could be a reason to have different expansions and contractions depending on the design goal.
Antone-
sumsound
1.) This again goes back to what your design is used for.
The DTS 20 is a Home Theater TH. Where as all my models and builds are for PA. Every one of them has been the same,needing to be right around 1/4 octave of the Fs. Else they get crazy peaks.
Everything in regards to HR was that
HR will allows you to see what your design is before you build. So you can use it to optimize until you feel it is as perfect as you can get it.
There is a good post on Horn loaded
compression ratio's though I cant recall if it's within these forums or Speakerplans.com forums. TH's should follow the same rules as it does come down to tensile strength of the cone etc. Though from what I have seen, over excursion is normally the culprit of failure. Failure due to compression would happen fairly quickly.
As far as the mouth and or horn path
variables. It all comes down to modeling and figuring out what is best for your given application. Since hash isn't a concern of mine
due to my intended usage (PA) I don't sweat anything above or below my intended frequency range because of EQing. I don't have to have the mouth canceling distortion or the like.
Unlike a Home Theater setup
that will more than likely \be designed for low power,low frequency output rather than max SPL . Xmax limitation is different. But since I want 130 plus DB, soon as you go below 40 Hz Xmax can go through the roof. I can build a 6th order isobaric bandpass that will do 15 Hz but not at 130 plus DB in a usable size or power consumption.
I am really interested in Danley's
new twin driver PA dubbed the "Hot Rods"
. I have been trying to model dual loaded TH's but haven't gotten it yet.
1.) This again goes back to what your design is used for.
The DTS 20 is a Home Theater TH. Where as all my models and builds are for PA. Every one of them has been the same,needing to be right around 1/4 octave of the Fs. Else they get crazy peaks.
Everything in regards to HR was that
HR will allows you to see what your design is before you build. So you can use it to optimize until you feel it is as perfect as you can get it.
There is a good post on Horn loaded
compression ratio's though I cant recall if it's within these forums or Speakerplans.com forums. TH's should follow the same rules as it does come down to tensile strength of the cone etc. Though from what I have seen, over excursion is normally the culprit of failure. Failure due to compression would happen fairly quickly.
As far as the mouth and or horn path
variables. It all comes down to modeling and figuring out what is best for your given application. Since hash isn't a concern of mine
due to my intended usage (PA) I don't sweat anything above or below my intended frequency range because of EQing. I don't have to have the mouth canceling distortion or the like.
Unlike a Home Theater setup
that will more than likely \be designed for low power,low frequency output rather than max SPL . Xmax limitation is different. But since I want 130 plus DB, soon as you go below 40 Hz Xmax can go through the roof. I can build a 6th order isobaric bandpass that will do 15 Hz but not at 130 plus DB in a usable size or power consumption.
I am really interested in Danley's
new twin driver PA dubbed the "Hot Rods"
. I have been trying to model dual loaded TH's but haven't gotten it yet.phase_accurate said:
I too would be interested in such a list...
Even a list of designs (speaker + cabinet sketch/plan) that just work would be really great (like the one from steve71 on page 95 of the main tapped horn thread).
I have been reading and lurking at the Tapped Horn Thread for a while now, but I must I cannot find my way around.
For this project , I will soon be looking at a good sub to take over from my (Beyma 10G40 powered) mains from about 100Hz/150Hz down to as low as possible (and as cleanly as possible).
If the tapped horn concept is as good as reviews seem to suggest (and "financialy efficient") I though that it might the right way to achieve clean bass on a quite extended range (not only 25 to 50 Hz as most sub do).
I am going the hardcore DIY route for my mains (starting from scratch) and having the hell of a job at filtering the mains but I must say that I would happily go the "lazzy route" and use a proven design for the sub, this has been too much hard work and I need a rest
. Any other pointers at tapped hor designs in "reasonably sized" enclosures that are proven and useable ?
The design from steve71 where the cabine is about 130 x 80 x 50 cm is OK but a maximum for me. Ideally, I would rather have something that could be a bit taller (more than 130cm, up to 160 cm is still good) and less wide (bringing back the 80cm to 60/50cm).
Many thanks (many many many) in advance if you have more links.
PS : BTW, I need to update the thead, might be able to find some help here...
No need fore that
But your post is a bit OT, and maybe better ask here http://www.diyaudio.com/forums/showthread.php?s=&threadid=97674
But your post is a bit OT, and maybe better ask here http://www.diyaudio.com/forums/showthread.php?s=&threadid=97674
About the required Fs...
For a normal horn, to get the most extended response at the LF corner (reactance cancellation) a rear compression chamber is usually required, which is equivalent to using a driver with a stiff suspension.
If you work out what the resonant frequency of the driver would be if its suspension was as stiff as (actual suspension + air in chamber) this is usually about 50% higher than the LF cutoff of the horn but this depends on the mass of the cone compared to the added air mass in the horn.
The required total stiffness for a tapped horn is no different if you want to get the best LF extension (using reactance cancellation), but since there's no rear chamber the driver suspension has to provide all the stiffness.
Also the increased stiffness helps restrict cone travel below the horn cutoff in the same way as a small rear chamber does in a normal horn.
Ian
For a normal horn, to get the most extended response at the LF corner (reactance cancellation) a rear compression chamber is usually required, which is equivalent to using a driver with a stiff suspension.
If you work out what the resonant frequency of the driver would be if its suspension was as stiff as (actual suspension + air in chamber) this is usually about 50% higher than the LF cutoff of the horn but this depends on the mass of the cone compared to the added air mass in the horn.
The required total stiffness for a tapped horn is no different if you want to get the best LF extension (using reactance cancellation), but since there's no rear chamber the driver suspension has to provide all the stiffness.
Also the increased stiffness helps restrict cone travel below the horn cutoff in the same way as a small rear chamber does in a normal horn.
Ian
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