AndrewT said:
Well, given a small enough Vb underground bunker I imagine it could, but it's academic because I didn't claim it would/could and AFAIK it would be useless anyway in any typical HIFI or HT app.
Regardless, unless the BW limits are defined as 'flat', then they are normally considered tuning frequencies, so my theoretical driver sim has a 10 Hz fundamental as shown and once damped should have at least a three octave usable ~flat BW based on my TL/pipe horn experience (not to mention DSL's and geitmans's measured responses as a frame of reference) and ~four octave tuning BW. I'd add that this assumes that HR is accurate enough, but I believe it's proven itself to be 'close enough' for the basic gain BW portion of its predictions that we can dispense with this disclaimer if the build mirrors the design input.
GM
Re: Re: Impulse Response
Yes.
Real world horn designs are almost always misaligned/compromised WRT the driver's specs to meet the needs of the intended app, so you get various throat, mouth distortions that cause reflections, pressure wave variations back to the driver if not damped as Dr. Geddes (foam insert) and/or Peavey (mouth foam surround) recommends. An optimized horn will have an impulse response that's 'close enough' to the driver's IB one and a compression horn's will be considerably better overall since its effective Qtc will be lower than the driver's Qts.
GM
AndrewT said:
Yes.
Real world horn designs are almost always misaligned/compromised WRT the driver's specs to meet the needs of the intended app, so you get various throat, mouth distortions that cause reflections, pressure wave variations back to the driver if not damped as Dr. Geddes (foam insert) and/or Peavey (mouth foam surround) recommends. An optimized horn will have an impulse response that's 'close enough' to the driver's IB one and a compression horn's will be considerably better overall since its effective Qtc will be lower than the driver's Qts.
GM
Re: Re: Impulse Response
That tapped horn needs more work. Look at the impulse response of one of my tapped horns.
http://www.diyaudio.com/forums/showthread.php?postid=1820883#post1820883
Rgs, JLH
AndrewT said:
That tapped horn needs more work. Look at the impulse response of one of my tapped horns.
http://www.diyaudio.com/forums/showthread.php?postid=1820883#post1820883
Rgs, JLH
JLH's B&C 8PE21 TH
Hi there JLH: The simulation for the 30hz TH shows he flattest frequency responce on the thread, which would cover the lowest note played by the piano (27.4hz) and cover the other orchestral bass instruments: string double bass, cello, bass clarinet, tuba, etc, this performance would be great for my listening. Did you post: a diagram, dimensions and does it use one or two B&C 8PE21's? What are your music listening observations of this TH? You have gotten a lots of laughs at our house from your "banned from the house" comments. .....regards, Michael
Hi there JLH: The simulation for the 30hz TH shows he flattest frequency responce on the thread, which would cover the lowest note played by the piano (27.4hz) and cover the other orchestral bass instruments: string double bass, cello, bass clarinet, tuba, etc, this performance would be great for my listening. Did you post: a diagram, dimensions and does it use one or two B&C 8PE21's? What are your music listening observations of this TH? You have gotten a lots of laughs at our house from your "banned from the house" comments. .....regards, Michael
Re: step response
There's a direct relationship between the amplitude/phase response and the impulse response of any loudspeaker, one is the FFT/IFFT of the other.
Anything which causes peaks in the frequency response (like an enclosure resonance) will cause ringing in the impulse response, which is generally undesirable but may or may not be audible.
Sharper rise/fall time simply means more HF bandwidth, and what limts the bandwidth (enclosure, voice coil inductance) makes little or no difference. For subwoofers the effect of voice coil inductance on limiting the frequency response is not usually a problem in itself, this happens well above the crossover frequency.
The real problem with high voice coil inductance is not so much that it limits bandwidth, but that it often varies greatly as the cone moves. This makes the bandwidth a function of cone position, which causes amplitude modulation of higher notes by lower ones as the cone moves in and out.
A driver with high but constant inductance is no different to an external inductor in series with the driver, like in a crossover. But this is difficult (and expensive!) to realise even using massive multiple demodulating rings and/or copper pole sleeves.
Ian
mwmkravchenko said:
There's a direct relationship between the amplitude/phase response and the impulse response of any loudspeaker, one is the FFT/IFFT of the other.
Anything which causes peaks in the frequency response (like an enclosure resonance) will cause ringing in the impulse response, which is generally undesirable but may or may not be audible.
Sharper rise/fall time simply means more HF bandwidth, and what limts the bandwidth (enclosure, voice coil inductance) makes little or no difference. For subwoofers the effect of voice coil inductance on limiting the frequency response is not usually a problem in itself, this happens well above the crossover frequency.
The real problem with high voice coil inductance is not so much that it limits bandwidth, but that it often varies greatly as the cone moves. This makes the bandwidth a function of cone position, which causes amplitude modulation of higher notes by lower ones as the cone moves in and out.
A driver with high but constant inductance is no different to an external inductor in series with the driver, like in a crossover. But this is difficult (and expensive!) to realise even using massive multiple demodulating rings and/or copper pole sleeves.
Ian
Post #3369
Hi electroaudio,
Good guess.
You are correct, the FLH in Post #3355 is not quite typical, the limit in box size was just too severe, and the impulse looks a bit like some bandpass models.
On the other hand the excess overshoot, and the ringing, are quite typical for an over-shortened horn with a mouth that is too small. The initial delay and sharp first impulse peak are typical for a FLH though.
Regards,
P.S.: Does anyone have a good Hornresp model suggestion for a MCM 55-2421 in a 1cft bandpass?
Hi electroaudio,
Good guess.
You are correct, the FLH in Post #3355 is not quite typical, the limit in box size was just too severe, and the impulse looks a bit like some bandpass models.
On the other hand the excess overshoot, and the ringing, are quite typical for an over-shortened horn with a mouth that is too small. The initial delay and sharp first impulse peak are typical for a FLH though.
Regards,
P.S.: Does anyone have a good Hornresp model suggestion for a MCM 55-2421 in a 1cft bandpass?
Re: JLH's B&C 8PE21 TH
I don't have that information on this computer. I'll post what I have when I get back over to my other computer.
Rgs, JLH
P.S. I'm glad you enjoy my humor. There is a certain satisfaction in building something so obnoxious it gets banned from the house.
j.michael droke said:
I don't have that information on this computer. I'll post what I have when I get back over to my other computer.
Rgs, JLH
P.S. I'm glad you enjoy my humor. There is a certain satisfaction in building something so obnoxious it gets banned from the house.
Re: Re: JLH's B&C 8PE21 TH
Now if you would just share some plans with the world, we can make antique tea-pots nervous the world over.
Charles
My wife is worried that I seem to have been inspired by your monster, I think that banning must be the ultimate tribute to subwoofer success.JLH said:
P.S. I'm glad you enjoy my humor. There is a certain satisfaction in building something so obnoxious it gets banned from the house.
Now if you would just share some plans with the world, we can make antique tea-pots nervous the world over.
Charles
Bluerex,
I don't have any construction details for you to follow, but I attached the Hornresp input parameters. It looks like Volvotreter's double folded W6-1139 tapped horn, but the woofers are arranged like the TH-SPUD. The Hornresp input parameters my not be 100% as to how I built it, but it is close enough.
Rgs, JLH
I don't have any construction details for you to follow, but I attached the Hornresp input parameters. It looks like Volvotreter's double folded W6-1139 tapped horn, but the woofers are arranged like the TH-SPUD. The Hornresp input parameters my not be 100% as to how I built it, but it is close enough.
Rgs, JLH
Attachments
this could be the wrong place to ask this...........but......
has anyone compared the "punisher" horn to a tapped horn ??
or at least put them into horn resp ?
would be interesting to see how the tapped horn stacks up
walt de jong designed the punisher and also a tapped horn variant any hornresgurus up for the sim - ing ?
punisher:
http://www.speakerstore.nl/constructions/21
Tapped (or "stepped" horn) horn
http://www.speakerstore.nl/constructions/61
ps i built two punshers albeit with lower quality drivers and they are a interesting beasty.. wondering how a tapped horn tuned in a similar way would stack up.
ie is a tapped horn better in terms of output than a more traditional folded horn ??
-Dan
has anyone compared the "punisher" horn to a tapped horn ??
or at least put them into horn resp ?
would be interesting to see how the tapped horn stacks up
walt de jong designed the punisher and also a tapped horn variant any hornresgurus up for the sim - ing ?
punisher:
http://www.speakerstore.nl/constructions/21
Tapped (or "stepped" horn) horn
http://www.speakerstore.nl/constructions/61
ps i built two punshers albeit with lower quality drivers and they are a interesting beasty.. wondering how a tapped horn tuned in a similar way would stack up.
ie is a tapped horn better in terms of output than a more traditional folded horn ??
-Dan
AndrewT said:
Based on my experience building and modeling conventional and tapped horns, a tapped horn *is* more efficient at low frequencies.
In other words, if you want maximum spl at 100hz, either design will work well, and a conventional horn will likely be flatter. But if you want maximum sub-bass output, a tapped horn is tough to beat.
This topic was explored in my thread named "tapped horn for dummies." The inventor of the tapped horn (Tom Danley) chimed in too.
Did anyone see this comparison of a tapped horn and a conventional horn?
http://srforums.prosoundweb.com/index.php/mv/msg/41911/0/0/0/
A couple of observations:
- I've been complaining for months that everyone is posting simulations in horn response that are wildly optimistic, because they're modeled using an unrealistic "radiation angle" in Hornresp. The measurements from the thread above back up my claim; they show that a conventional horn and a tapped horn have similar efficiency above 60hz.
- The tapped horn is surprisingly smooth above 60hz. This confirms what Danley has noted, that the simulations exaggerate the peaks and the dips in a tapped horn.
- The tapped horn is displaying a full 6db of extra output at 40hz! Nice
- It's interesting to see that grouping two together doesn't lower the F3. I'd love to hear someone do a concert where the subs were distributed around the venue, to flatten the response, instead of grouped together. Last week I went to an Imax theater where the subs were all grouped together, and you could hear some definite room effects from the stack. (I use eight subs at home, distributed to flatten the response. My home subs definitely sounded more natural than the Imax subs.)
Just some observations...
http://srforums.prosoundweb.com/index.php/mv/msg/41911/0/0/0/
A couple of observations:
- I've been complaining for months that everyone is posting simulations in horn response that are wildly optimistic, because they're modeled using an unrealistic "radiation angle" in Hornresp. The measurements from the thread above back up my claim; they show that a conventional horn and a tapped horn have similar efficiency above 60hz.
- The tapped horn is surprisingly smooth above 60hz. This confirms what Danley has noted, that the simulations exaggerate the peaks and the dips in a tapped horn.
- The tapped horn is displaying a full 6db of extra output at 40hz! Nice
- It's interesting to see that grouping two together doesn't lower the F3. I'd love to hear someone do a concert where the subs were distributed around the venue, to flatten the response, instead of grouped together. Last week I went to an Imax theater where the subs were all grouped together, and you could hear some definite room effects from the stack. (I use eight subs at home, distributed to flatten the response. My home subs definitely sounded more natural than the Imax subs.)
Just some observations...
Eight subwoofers
Hi there Patrick: Your system must sound great with distributed bass. I'm contmplating a multiple sub system and have a few questions: What connection scheme di you use? Wire (lots of wire)? Wireless? How many bass amps? Is there phase control in use? I recently read the Harman Int. study by Todd Welti, which studied the placement of multiple subs: what placement did you use? Baybe this subject should be in a diferent thread? ....... regards, Michael
Hi there Patrick: Your system must sound great with distributed bass. I'm contmplating a multiple sub system and have a few questions: What connection scheme di you use? Wire (lots of wire)? Wireless? How many bass amps? Is there phase control in use? I recently read the Harman Int. study by Todd Welti, which studied the placement of multiple subs: what placement did you use? Baybe this subject should be in a diferent thread? ....... regards, Michael