This is fascinating to me! what a job to haverolfy72 said:
My brother-in-law worked as a F-16 engineer and told me stories about after burners and the incredible sounds they make, i think because your in an encloused space the sound is trapped and with Jet engines the sound and energy is forced in one direction into an wide open space, am sure its similar but i have never been that close to a Jet engine! and i have never been to a lead mill! I am not sure about the U shapes effects on the sound but am sure its has a purpose, Its well known that big bush fires have infra sound and animals run well before they can even smell the fire, i know some get toasted but i dont know how animals think! Thanks for the info
it put a smile on my faceSYNERGY:
I love your idea about “blowing over a bottle”.
I blew over a 5 gallon glass jug recently and got some REAL DEEP BASS – much more than my mouth’s FS
As you may or may not know, I have a Bose Cannon tuned to ~20HZ(15’) to ~60HZ(5’) using a JBL LE14A which has an FS of 28HZ and a Q of .3
By adding this chamber tuned to 15HZ maybe I could pick up another ½ (or so) octave of DEEP BASS?
It seems that Graham Holliman’s designs “blow over” the chamber as close as possible to the location of the driver.
Perhaps this is an area for investigation (as you mention)?
Logically, one would think that the chamber port be as close as possible to the OTHER end of the (in my case 15’) pipe – where there is SIGNIFICANT energy going by?
If we concentrate this method into a very narrow DEEB BASS range maybe we can get somewhere?
HEY – I’d love to be flat from 15HZ to 60HZ instead of 20HZ to 60HZ.
Savvy?
SRETEN:
What do you think big guy? Is there anything here? Or am I whistling dixie (as usual)...
I love your idea about “blowing over a bottle”.
I blew over a 5 gallon glass jug recently and got some REAL DEEP BASS – much more than my mouth’s FS
As you may or may not know, I have a Bose Cannon tuned to ~20HZ(15’) to ~60HZ(5’) using a JBL LE14A which has an FS of 28HZ and a Q of .3
By adding this chamber tuned to 15HZ maybe I could pick up another ½ (or so) octave of DEEP BASS?
It seems that Graham Holliman’s designs “blow over” the chamber as close as possible to the location of the driver.
Perhaps this is an area for investigation (as you mention)?
Logically, one would think that the chamber port be as close as possible to the OTHER end of the (in my case 15’) pipe – where there is SIGNIFICANT energy going by?
If we concentrate this method into a very narrow DEEB BASS range maybe we can get somewhere?
HEY – I’d love to be flat from 15HZ to 60HZ instead of 20HZ to 60HZ.
Savvy?
SRETEN:
What do you think big guy? Is there anything here? Or am I whistling dixie (as usual)...
forgive the delay other things have stopped me from working on this too much and i went on holiday for a while
however the good news is using a T-Line form this does actually appear to work
the downside being there's no way to get around the simple fact that the air needs to be moved in the first place and consequently a large driver and/or Xmax is needed
also because of the low frequencies and lack of significant loading on the driver it doesn't take much power at all to reach the excursion limits of your chosen driver
to keep the size down to practical limits i've been modelling this using a Shiva in a tapered T-Line tuned to it's Fs (the taper appears to load the driver slightly and definately helps smooth the response)
first off the response plot
blue line = TL without chamber
black line = TL with resonant chamber
green line and cross = max spl at Xmax
it's worth noting that the TL on its own brings home an 8Hz signal at 50dB that's a massive 30dB down compared to the TL with the chamber
in response to qi's query over the position it definately seems to want to be close to the driver for the widest bandwidth
position
black line = driver end
blue line = middle
green line = open end
so anybody want to venture a better driver than the shiva?
i'm thinking v. low Fs, Qts and Vas with an Xmax to die for - hows the parthenon doing?
dave
however the good news is using a T-Line form this does actually appear to work
the downside being there's no way to get around the simple fact that the air needs to be moved in the first place and consequently a large driver and/or Xmax is needed
also because of the low frequencies and lack of significant loading on the driver it doesn't take much power at all to reach the excursion limits of your chosen driver
to keep the size down to practical limits i've been modelling this using a Shiva in a tapered T-Line tuned to it's Fs (the taper appears to load the driver slightly and definately helps smooth the response)
first off the response plot
blue line = TL without chamber
black line = TL with resonant chamber
green line and cross = max spl at Xmax
it's worth noting that the TL on its own brings home an 8Hz signal at 50dB that's a massive 30dB down compared to the TL with the chamber
in response to qi's query over the position it definately seems to want to be close to the driver for the widest bandwidth
position
black line = driver end
blue line = middle
green line = open end
so anybody want to venture a better driver than the shiva?
i'm thinking v. low Fs, Qts and Vas with an Xmax to die for - hows the parthenon doing?
dave
no drawings i'm afraid this is all modeled in virtual space
the T-Line was tapered 1:0.2 Sd and the duct to the chamber was placed 10cm from the ends of the line with the driver not moving from it's position at the closed end
i dare say a little playing around with driver and chamber positions may yield better results but i was really after suggestions for a better driver than the shiva before i continue further (pref one i can get in the uk)
dave
the T-Line was tapered 1:0.2 Sd and the duct to the chamber was placed 10cm from the ends of the line with the driver not moving from it's position at the closed end
i dare say a little playing around with driver and chamber positions may yield better results but i was really after suggestions for a better driver than the shiva before i continue further (pref one i can get in the uk)
dave
Can it bee seen as if the mass of air in the duckt is added to the driver, and the outlet duck aligned to the system somthing near Qb3 ? i think it may give an idea of how deap it can go(?)
Finaly i think that cavity resonators and their behavior regards self damping (d) is not realy somthing to aim for if you are aiming transient respons rather than freq response.
Or how abt modify the model of resistive chamber copling ?
After all the electrical feedback to the amp regarding damping must bee considered as 'lost in velosity'. After all it's blowing a big bottle tuned with a narrow bandwith resonance isnt it ?
Finaly i think that cavity resonators and their behavior regards self damping (d) is not realy somthing to aim for if you are aiming transient respons rather than freq response.
Or how abt modify the model of resistive chamber copling ?
After all the electrical feedback to the amp regarding damping must bee considered as 'lost in velosity'. After all it's blowing a big bottle tuned with a narrow bandwith resonance isnt it ?
I think someone should design a TL flat down to sub 10hz for an atlas 15" many reasons, heres some of them
-Cheap driver
-3litres LINEAR displacement
-much more maximum displacement due to XBL^2
-relatively low fs
-realtively low(or adjustable) QTS
- I own one, and i just loooooooooove low bass!
Whats the efficiency of a TL compared to a sealed box?
-Cheap driver
-3litres LINEAR displacement
-much more maximum displacement due to XBL^2
-relatively low fs
-realtively low(or adjustable) QTS
- I own one, and i just loooooooooove low bass!
Whats the efficiency of a TL compared to a sealed box?
So who has actually built this thing? Paradise, BA?
A link in a recent thread on this one shows a word document which has all the dimensions for a given driver size. The design is already done. You just have to adapt it slightly for the particular mounting requirements of your driver, and make some allowances if its for a driver like the Tumult with a large surround and excursion, hence requiring some clearance to allow for its excursion.
A link in a recent thread on this one shows a word document which has all the dimensions for a given driver size. The design is already done. You just have to adapt it slightly for the particular mounting requirements of your driver, and make some allowances if its for a driver like the Tumult with a large surround and excursion, hence requiring some clearance to allow for its excursion.
paulspencer said:
Yea with some modifications to make it modular so I can swap vents and resonator chambers ect. I want to get a "feel" for what the design is doing, mabie get a "rule of thumb" sorted out.
As I see it I should be able to compare the line with the resonator attached to the output of just the TL by it's self.
Hi Volenti, and others,
Any progress here? Any first impressions?
Everytime I see this Holliman thing coming 'round, I feel like "hm... wanna try this..." but still a bit anxious to waste pennies.
Haven't got the space to place it, and I'm not sure wether my room suits this 'thing' or not. Not even sure if I have the wood skills to build it...
Read a long thread about this over at the decware forum as well, but both that one and this one sort of stopped about 2 weeks ago...
Now if someone (or more!) happend to give some (hopefully good) impressions, that might convince me....
Good luck building 'it' (And speed up the process, so I can start!
)
Paul
Any progress here? Any first impressions?
Everytime I see this Holliman thing coming 'round, I feel like "hm... wanna try this..." but still a bit anxious to waste pennies.
Haven't got the space to place it, and I'm not sure wether my room suits this 'thing' or not. Not even sure if I have the wood skills to build it...
Read a long thread about this over at the decware forum as well, but both that one and this one sort of stopped about 2 weeks ago...
Now if someone (or more!) happend to give some (hopefully good) impressions, that might convince me....
Good luck building 'it' (And speed up the process, so I can start!
)Paul
Did you see the thread I started (5 - 25 hz is the thread title) to try to discuss the theory of this design and regenerate interest? There are only a couple of guys that bothered to comment at all. I think I have a decent handle on how this thing works, but of course only a single person has even commented on my ideas and he does not agree with me.
In that thread I posted a few good links to all the pertinent info I could possibly find but I did not link to the decware thread because as far as I am concerned it contains no useful information that is not already covered by the other links.
Of course there are more because this was once a commercial product, but I can only find evidence that 2 people in the world have made this box, one of them made a 10 inch version, and the other a 15. By all accounts, both were very happy with the results.
I am very confused by the seeming total lack of interest in this box. It has been around for decades but the only info I can find is what I have posted and linked to. Besides a few offhand comments no one seems to even want to discuss this design. I have only had the plans for a month or two now but I will definitely be building one as soon as possible (which unfortunately will not really be all that soon).
I am seeing claims that this box will do 5 - 25 hz with sensitivity values that rival high effieciency fullrange drivers and exceptionally low distortion. How can there be no interest in this?
Maybe there is no interest in the frequency range of 5 - 25 hz for most people. Maybe people who understand the design better than I do have considered this idea and found it to be flawed somehow and not worth the time or money. Perhaps people know of better ways to reproduce 5 hz. I have researched the possiblity of getting down to 10 hz (certainly not 5) with readily available drivers and box types and have found that meaningful SPL levels require massive driver excursion and cone area combined with massive amplifiers. Basically about $1000 to do properly (but still modestly). Although I have no actual measured numbers from the Holliman box, I do know that the 10 inch version can be made for under $100 (driver included) and it can be powered adequately with any amp you have lying around.
This seems like a very cost effective experiment in the money hungry world of infrabass and the cost would be worth the learning experience even if it didn't work.
So again, where is the interest in this design? It's like pulling teeth to even get people to discuss it.
In that thread I posted a few good links to all the pertinent info I could possibly find but I did not link to the decware thread because as far as I am concerned it contains no useful information that is not already covered by the other links.
Of course there are more because this was once a commercial product, but I can only find evidence that 2 people in the world have made this box, one of them made a 10 inch version, and the other a 15. By all accounts, both were very happy with the results.
I am very confused by the seeming total lack of interest in this box. It has been around for decades but the only info I can find is what I have posted and linked to. Besides a few offhand comments no one seems to even want to discuss this design. I have only had the plans for a month or two now but I will definitely be building one as soon as possible (which unfortunately will not really be all that soon).
I am seeing claims that this box will do 5 - 25 hz with sensitivity values that rival high effieciency fullrange drivers and exceptionally low distortion. How can there be no interest in this?
Maybe there is no interest in the frequency range of 5 - 25 hz for most people. Maybe people who understand the design better than I do have considered this idea and found it to be flawed somehow and not worth the time or money. Perhaps people know of better ways to reproduce 5 hz. I have researched the possiblity of getting down to 10 hz (certainly not 5) with readily available drivers and box types and have found that meaningful SPL levels require massive driver excursion and cone area combined with massive amplifiers. Basically about $1000 to do properly (but still modestly). Although I have no actual measured numbers from the Holliman box, I do know that the 10 inch version can be made for under $100 (driver included) and it can be powered adequately with any amp you have lying around.
This seems like a very cost effective experiment in the money hungry world of infrabass and the cost would be worth the learning experience even if it didn't work.
So again, where is the interest in this design? It's like pulling teeth to even get people to discuss it.
just a guy said:
IMO it looks fundamentally flawed (as previously discussed and modeled). Even as a relativly low cost project - it doesn't seem to merit the time and effort to try it.
Just because 2 others have built it and like it doesn't mean that the device is actually operating as *advertised* (generally, or in a patent).
While I could well be wrong, I think that you will continue to be "pulling teeth" on this subject until decent measurements are made from a good "working" example.
This isn't to condemn the concept, but rather to say "I'll wait and see" until it objectivly peaks my interest.
Do you understand now?
If a 10" driver could reach 95 db efficiency from 5-25 Hz and do it with accuracy, there would be a flood of interest. I think most feel it's too good to be true, and assume that it would be very inaccurate, or simply wouldn't prove to be efficient. Also many don't have a suitable room.
I wouldn't say there is no interest. I think most would like to see some results first. I'm interested to see your results and comments after you build it.
I wouldn't say there is no interest. I think most would like to see some results first. I'm interested to see your results and comments after you build it.
bibster said:Hi Volenti, and others,
Any progress here? Any first impressions?
Everytime I see this Holliman thing coming 'round, I feel like "hm... wanna try this..." but still a bit anxious to waste pennies.
Haven't got the space to place it, and I'm not sure wether my room suits this 'thing' or not. Not even sure if I have the wood skills to build it...
Read a long thread about this over at the decware forum as well, but both that one and this one sort of stopped about 2 weeks ago...
Now if someone (or more!) happend to give some (hopefully good) impressions, that might convince me....
Good luck building 'it' (And speed up the process, so I can start!
Paul
I pretty much only have one modular section left to build and mine will be ready to go, I'll post pics and impressions, good or bad, when it's done and I've had time to play with it.
Ok, understood, Scott. But if it did actually perform as modelled here, he would not have been granted a patent (I don't think you can patent wild, unsubstantiated claims), this would not have been a commercial product, there would be no evidence whatsoever of anyone being happy with it and furthermore there should be at least one person WITH EXPERIENCE to contradict the claims. Or maybe it sucked so bad that it bombed commercially with few to no units sold and that's why there is not much information.
Either way I don't care, I'm going to at least try it. Too good to be true? Maybe but I see potential here.
Either way I don't care, I'm going to at least try it. Too good to be true? Maybe but I see potential here.