Thinking about this again ive understood that conicals were worse regarding the low end response ??
See here page 12.
Keele (1975-05 AES Preprint) - Whats So Sacred Exp Horns-1.pdf
Can be found here --> http://www.dbkeele.com/papers.htm
later, Collin
See here page 12.
Keele (1975-05 AES Preprint) - Whats So Sacred Exp Horns-1.pdf
Can be found here --> http://www.dbkeele.com/papers.htm
later, Collin
The Pi horn uses the jbl2012 driver, or the eminence delta 10. Wayne has stated that these both have 'rising' responses on axis, which seem to counteract the eq that Rcw has used.
Rob.
Rob.
Hi Rob, All
I've struggled a bit with this one.
In my very humble opinion ( yeah, right 😉 )
the frequency area most difficult to get "right" is from say 80 Hz and up a bit, maybe to 2000Hz , or so. Upper bass and lower midrange.
That frequency area would IHMO best be covered by the midbass- and midrange horn in a full 4-way horn system. People who can hear good over 15KHz might want to add a tweeter to cover from 10-15KHz and up, making it a 5-way horn system.
You are considering using a labhorn on the bottom, I would use two if I was you. 😉. I have heard such a setup here in Norway, two on top of each other along the front wall fireing into the corner. Low bass is effortless and goes all the way down in that room. I would cross over to the midbasshorn as low as possible, like maybe 60Hz, or so.
Use a reasonably big amplifier....
That's the easy part.
IMHO one of the biggest problems with using horns in your living room is that a good horn is a full-size horn. Whenever you shorten a horn, or use a smaller than optimum horn-mouth your horn don't really work as a horn anymore, but more like some sort of resonant bastard...
This includes any backloaded Lowther horn I've seen and even the labhorns. They are all compromises, and you have to listen to them and try to figure out what compromises you can live with in the long run.
It all depends on your room, you ampifiers and your listening habits,
among other things. The more horns you can listen to yourself the better. I that light it is difficult to give good advise on midhorns.
What works for my me might be horrible to you.
I have allready stated my opinion on shortened conicals,
so I won't go there.
I'll stop now, realizing that I haven't helped at all,
so to not make things even more confusing....
cheers 😉
RobWells said:
I've struggled a bit with this one.
In my very humble opinion ( yeah, right 😉 )
the frequency area most difficult to get "right" is from say 80 Hz and up a bit, maybe to 2000Hz , or so. Upper bass and lower midrange.
That frequency area would IHMO best be covered by the midbass- and midrange horn in a full 4-way horn system. People who can hear good over 15KHz might want to add a tweeter to cover from 10-15KHz and up, making it a 5-way horn system.
You are considering using a labhorn on the bottom, I would use two if I was you. 😉. I have heard such a setup here in Norway, two on top of each other along the front wall fireing into the corner. Low bass is effortless and goes all the way down in that room. I would cross over to the midbasshorn as low as possible, like maybe 60Hz, or so.
Use a reasonably big amplifier....
That's the easy part.
IMHO one of the biggest problems with using horns in your living room is that a good horn is a full-size horn. Whenever you shorten a horn, or use a smaller than optimum horn-mouth your horn don't really work as a horn anymore, but more like some sort of resonant bastard...
This includes any backloaded Lowther horn I've seen and even the labhorns. They are all compromises, and you have to listen to them and try to figure out what compromises you can live with in the long run.
It all depends on your room, you ampifiers and your listening habits,
among other things. The more horns you can listen to yourself the better. I that light it is difficult to give good advise on midhorns.
What works for my me might be horrible to you.
I have allready stated my opinion on shortened conicals,
so I won't go there.
I'll stop now, realizing that I haven't helped at all,
so to not make things even more confusing....
cheers 😉
Ok Thanks Jan.
I am actually building 4 labhorns (just in case I ever get a room big enough) and will be using 2 against the front wall corner loaded.
I'll build the Pi horns for now and let you know what I think of them.
Cheers,
Rob.
I am actually building 4 labhorns (just in case I ever get a room big enough) and will be using 2 against the front wall corner loaded.
I'll build the Pi horns for now and let you know what I think of them.
Cheers,
Rob.
slowmotion said:
Greets!
Bingo! For a conical 300-1200 Hz, I'd want it to have at least a 106 Hz 'Sm'/half WL long (including any boundaries) with a (0.707*1200) 'St'. Ideally the driver would have a ~2:1 CR at this 'St' and a (0.707*300) mass corner, and of course have a ~flat HF BW to at least 1200 Hz. Then it's just a matter of finding the compression chamber's Vb that resonates it at 300 Hz.
GM
Ok it looks like I'm going to have to take a couple of weeks off the forum to read up on horn design. I'm getting lost here.😱
GM, Are you saying I should stick with my direct radiators rather than even trying the Pi horns?
Cheers,
Rob
GM, Are you saying I should stick with my direct radiators rather than even trying the Pi horns?
Cheers,
Rob
re horns
Tests done on conical horns show that they do in fact have more output at the lower end than simple theory would suggest, this is due to the mass reactance of the air.
With a compression driver the responce is the same as it is on a plane wave tube, i.e. it is flat up to its mass corner and then rolls off above that at 6db. per octave, the cone driver is typically at or above its mass corner below or near cut off so it acts as a compression driver does above its mass corner.
The actual upper final upper roll off is next affected by some combination of the two next break frequencies, fhvc=the voice coil inductance effect, and fhc=the throat cavity cut off.
Tests done on conical horns show that they do in fact have more output at the lower end than simple theory would suggest, this is due to the mass reactance of the air.
With a compression driver the responce is the same as it is on a plane wave tube, i.e. it is flat up to its mass corner and then rolls off above that at 6db. per octave, the cone driver is typically at or above its mass corner below or near cut off so it acts as a compression driver does above its mass corner.
The actual upper final upper roll off is next affected by some combination of the two next break frequencies, fhvc=the voice coil inductance effect, and fhc=the throat cavity cut off.
RobWells said:
Greets!
No, I was agreeing with Jan and elaborated a bit as to what would work for me. My bad, I'll know better next time. If I thought you'd be completely wasting your time/$$ on WP's design I'd of said so. I mean I haven't researched his design much and I gather he relies on whatever EQ is required to flatten its response, but it's pretty hard to FUBAR a conic flare to the point where it's completely unusable. I just prefer to solve acoustic problems with acoustic solutions as much as practical. Unfortunately, this usually means a larger speaker than many (most?) will tolerate.
Anyway, his design is as good a way as any to 'get your feet wet' with horns, so experiment with XOs, EQ, TD, reactance annulling, flared end corrections and let us know what you think.
GM
re 2012
The 2012 has a rising on axis frequency reponce of around 6db. octave from around 80-1000Hz. its mass corner occurs at around 580Hz.
The 2012 has a rising on axis frequency reponce of around 6db. octave from around 80-1000Hz. its mass corner occurs at around 580Hz.
Hi all
Rob, 4 labhorns seems to me to be just about right.
Horns are generally just as different from each other as direct radiating
loudspeakers, so any personal experience you get is very important.
Start with what you feel comfortable with, and be prepared for a long
and very rewarding journey.
How big is you room again? ( lenght x width )
cheers 😉
Rob, 4 labhorns seems to me to be just about right.
Horns are generally just as different from each other as direct radiating
loudspeakers, so any personal experience you get is very important.
Start with what you feel comfortable with, and be prepared for a long
and very rewarding journey.
How big is you room again? ( lenght x width )
cheers 😉
Hi all
GM, it seems we think somewhat alike on this subject, good to hear!
Presently I am working on trying to get the horisontal coverage angle
to stay as similar as possible over as big a frequency range as possible,
while still wanting the horns to load the drivers as uniform as possible.
Possibly....
( Also I have to work on writing shorter sentences 😉 )
cheers 😉
GM, it seems we think somewhat alike on this subject, good to hear!
Presently I am working on trying to get the horisontal coverage angle
to stay as similar as possible over as big a frequency range as possible,
while still wanting the horns to load the drivers as uniform as possible.
Possibly....
( Also I have to work on writing shorter sentences 😉 )
cheers 😉
Re: re horns
So you need to add the mass of air in the horn to mms and calculate the mass corner (insert formula here) or just geustimate that you would be atleast an octave below the upper -6 db SPL ?
I have noticed this with some testing i have done. Loading the driver with larger horns tilted the responce more to the low end or cut the highs, whitch one i dont know i didnt measure.
rcw said:
So you need to add the mass of air in the horn to mms and calculate the mass corner (insert formula here) or just geustimate that you would be atleast an octave below the upper -6 db SPL ?
I have noticed this with some testing i have done. Loading the driver with larger horns tilted the responce more to the low end or cut the highs, whitch one i dont know i didnt measure.
GM said:
Hi GM,
a few questions from a newbie.
How can the mass corner be below 300Hz and the driver still have a flat responce to 1200 Hz ? Or do you mean output without the horn?
With compresion drivers many manufacturers give the plane wave tube SPL responce. Is this kind of misleading because there is no added air mass of the horn ?
I geuss this gives me the answer to my first qeustion a few post back regarding the upper bandwidth of 3-4 octaves higher than the lower cutoff.
Also i can understand you'd want the horn mouth "overspecified" to an octave+ below 300Hz but why the 0.707*1200 throat ?
These ideal horns dont give any leeway regarding coverage angles do they 🙂
Just learning from all the experts here !
Regards,
Collin
Ok GM, will get moving on them as soon as my mdf turns up.
Jan, my room is a fairly small 21' x 10 ' Not ideal I know.
Cheers,
Rob
Jan, my room is a fairly small 21' x 10 ' Not ideal I know.
Cheers,
Rob
Hi
But not to bad either,
a bit narrow, but good lenght.
I'm sure you can get some good music going in there 😉
cheers 😉
RobWells said:
But not to bad either,
a bit narrow, but good lenght.
I'm sure you can get some good music going in there 😉
cheers 😉
Re: Re: re horns
Hi,
When you say larger, did you keep the throat the same and made the horn longer and with a bigger mouth ( lower cutoff )?
Or did you use a bigger throat as well?
cheers 😉
Hi,
Coolin said:
When you say larger, did you keep the throat the same and made the horn longer and with a bigger mouth ( lower cutoff )?
Or did you use a bigger throat as well?
cheers 😉
Re: Re: Re: re horns
Same throat size but a little longer and thus greater mouth area.
Collin
slowmotion said:
Same throat size but a little longer and thus greater mouth area.
Collin
re mass corner
The mass corner is a result that comes from analysing the electroacoustic analogue of a driver and horn combination, in T-S parameters it is.
(2Fs)/Qts
The acoustic power out put drops off above this frequency.
The mass corner is a result that comes from analysing the electroacoustic analogue of a driver and horn combination, in T-S parameters it is.
(2Fs)/Qts
The acoustic power out put drops off above this frequency.
Horn bass
I thought about using horn bass. I dropped that idea when I realized that I could not get as deep as I would like, and that there would be a phase issue with the mains. The huge boxes to get down fairly low are another issue.
I would be interested to know how your experiment works out by firing two lab horns in the corner. You might have to sit on the monopole subs if you want to go deeper
considering the room size. What you will get will be impressive, even with the phase differences.
I am opting for infinite baffle bass eventually, although I don't have the right situation right now for that. In the short term I am putting a pair of 15 inch and another pair of 18 inch drivers (Avalanche Audio) on open baffles. This should get me pretty low (probably to 20 hz) at normal listening levels (~90 db with at least 10 db of head room) even in open baffles.
Of the types of bass which are possible, I would consider horn, infinite baffle and open baffle the best, with open baffle helping with reducing room nodes, but struggling with getting down low. I would not consider reflex designs, and shy away from sealed except for servos. I had a Genesis 900 servo controlled sub until the amp died. It had truly great bass (after Genesis modified their accelerometer attachment in my driver). The crossover was very adjustable which simplified the crossover with the main speakers, allowing absolutely perfection in the crossover. Until such perfection is achieved, the system never sounds quite right.
Retsel
I thought about using horn bass. I dropped that idea when I realized that I could not get as deep as I would like, and that there would be a phase issue with the mains. The huge boxes to get down fairly low are another issue.
I would be interested to know how your experiment works out by firing two lab horns in the corner. You might have to sit on the monopole subs if you want to go deeper
considering the room size. What you will get will be impressive, even with the phase differences.I am opting for infinite baffle bass eventually, although I don't have the right situation right now for that. In the short term I am putting a pair of 15 inch and another pair of 18 inch drivers (Avalanche Audio) on open baffles. This should get me pretty low (probably to 20 hz) at normal listening levels (~90 db with at least 10 db of head room) even in open baffles.
Of the types of bass which are possible, I would consider horn, infinite baffle and open baffle the best, with open baffle helping with reducing room nodes, but struggling with getting down low. I would not consider reflex designs, and shy away from sealed except for servos. I had a Genesis 900 servo controlled sub until the amp died. It had truly great bass (after Genesis modified their accelerometer attachment in my driver). The crossover was very adjustable which simplified the crossover with the main speakers, allowing absolutely perfection in the crossover. Until such perfection is achieved, the system never sounds quite right.
Retsel
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