[victorvector]

Hello everyone.

I have a question about the design of some some front loaded horn enclosures .
I often see this type of horn enclosure  ,  and what puzzles me is how the designer determines how much of the cone area is covered by the horn structure ( or baffle ) in front of it.









Is this a design function specific to the driver ( e.g. its T&S parameters ) , or  some other method.
The amount of frontal cone area covered by the horn structure does seem to vary considerably .

Can anyone here briefly explain the process to determine this seemingly varied dimension ?

Thank you  in advance  for any help with this.

Vic.

[FullRangeMan]

Well Iam really no expert in the subject and cant response your question without a search, but I suspect its no rocket science. However this type of horn design figured above are used in low quality plastic horns and even pro-audio horns for mid range and hi freq drivers.

IMO the horn neck dont cover the entire driver dome area, at least in the horns I have see in loco, since these horns are not circular, but limited vertically, for this these horns are also named compression horns.

A more suited horn for hi fi audio are these round horns mainly in real wood.
My 2 cents.
https://sites.google.com/site/diyfirefly/320-hz-round-tractrix-horns

[victorvector]

Hi FullRangeMan

About the last thing I expected to find in front of a horn , is a  " compression chamber " ..........

Like this ......









Really puzzled  by this.

Apparently often seen on higher end speakers too ?

[JLM]

There's a ton of math behind proper horn design.  But note that to be effective as a bass horn, it must be huge and highly reinforced.  Take the Klipsch-horn as an example.  It ingeniously uses room corner (9 feet of continuous wall on both sides) to complete the horn, but the cabinet walls are not sufficiently braced in the opinion of many and yet is only rated down to 40 Hz.  A more successful design is reinforced concrete horns (the size of a garage).  Just think of the size of the sound waves involved (20 Hz = 56 feet, 50 Hz = 22.6 feet) and this starts to make sense. 

An internet search should reveal some of the modern midrange/tweeter horn designs. 

[victorvector]

Reinforced concrete horns the size of a garage are not on my radar JLM....

But I do understand  where you are coming from.

Luckily , I mostly like listening to a wide variety of music at rather "sedate" SPL ...

[JLM]

Didn't imagine you'd be willing to go as far as a garage sized concrete horns. 

Please understand that this isn't an issue about sound pressure levels (SPL), it's about reaching low bass frequencies.  With the size of sound waves involved in bass, the flared openings in your pictures are only there for much higher frequencies (say above 500 Hz). 

I run three subs, not to reach high SPL's but to help control inherent in-room bass peaks/dips.  Refer to Floyd Toole's "Sound Reproduction" 3rd edition for a good explanation.  The volume levels on my subs are set at around 25%.  The key to selecting the right sub is for it to be "fast" (typically a sealed sub is better than ported at this) and to reach the lowest frequencies.  SVS SB-1000 or Rythmik L12 are good, affordable candidates.  Short of a garage sized concrete horn the next best designs are transmission lines, but harder to design than sealed or ported (search Martin King MathCad application) and require a bit larger cabinet (don't know of any commercially available ones). 

[victorvector]

Yes , seems to me it`s  more difficult and expensive to get fast clean base at SPL that match sensitive speakers.

I was under the impressions that those horn cabinets pictured earlier would make good full range enclosures ?

I may be in the minority here , but don`t  feel the need to get down to 20 Hz ( really don`t enjoy Bach anyway ) 

I bet your system sounds awesome though.

I am reading about some of Mr. King`s work at the moment.

 

[JLM]

Large drivers will "beam" (narrow dispersion) at higher midrange frequencies and beyond, thus the popularity of tweeters.  Classic large extended range drivers typically use whizzer cones to overcome this issue but even then had ratings like 80-8,000 Hz (which was considered "full range" decades ago). 

Agree with the 20 Hz extension.  20-20,000 Hz is more of a snappy marketing ploy than anything else.  However if you want to feel dinosaur footfalls you'll need to reach below the range of non-pipe organ music (30 Hz).  Reaching deep comes with a whole range of problems.  Most speakers and many subs aren't rated to go that low.  Room gain offsets the need for speakers to offer flat response that low anyway.  And resonances in the room pop up with all that bass energy in the room.  Plus there's the "brown sound" issue.    

Note that the challenge of matching efficiency of woofers with tweeters goes away with the use of powered subwoofers. 

[FullRangeMan]

[Letitroll98]

Plus there's the "brown sound" issue.

One might assume you're referring to Brownian Noise, the spectrum produced by Brownian Motion, represented by the inverse of f2?  Which, surprisingly, is what Einstein won the Nobel for, not relativity.

Perhaps Eddie van Halen's famous "brown sound" amp distortion, producing that warm guitar fuzz that so distinguished his music?

Surely it's not bass so low and powerful that ones pants turn brown, at least that would keep the adult diaper business in good stead in your listening room.

[victorvector]

Agree with the 20 Hz extension.  20-20,000 Hz is more of a snappy marketing ploy than anything else.  However if you want to feel dinosaur footfalls you'll need to reach below the range of non-pipe organ music (30 Hz).  Reaching deep comes with a whole range of problems.  Most speakers and many subs aren't rated to go that low.  Room gain offsets the need for speakers to offer flat response that low anyway.  And resonances in the room pop up with all that bass energy in the room.  Plus there's the "brown sound" issue.    

Note that the challenge of matching efficiency of woofers with tweeters goes away with the use of powered subwoofers.

I think you have summed that up perfectly.

In the end , it may well be the simplest way to go.

I built a 12 inch big sub ( 110 liters ) that served me well for 13 years , until the plate amp suddenly died.

I will replace that plate amp .

I hope you don`t mind me asking , but why are you running three subs JLM ?
Is it because of Home theatre ?

For stereo music ,  I found that one was plenty for my use ?

[FullRangeMan]

In my experience 40Hz are plenty of bass for my taste.

[JLM]

I think you have summed that up perfectly.

I hope you don`t mind me asking , but why are you running three subs JLM ?
Is it because of Home theatre ?

For stereo music ,  I found that one was plenty for my use ?

See my reply #5 above.  I follow the teachings of Floyd Toole.  In-room bass behaves like moving your hand back and forth in a partially filled bathtub.  The waves hit one end and then rebound.  When the rebound hits the next wave they either double up, cancel, or interfere with each other.  That translates into up to 20 dB peaks/dips in-room.  Absorption helps, but best to deal with the distributing bass sources around the room.  From Toole's and Geddes research that is best done with 3 or 4 subs located near the corners.  Toole even suggest locating one higher up and having one set 180 degrees out of phase.  What frequency(ies) it occurs at is simply a function of primary room dimensions and the speed of sound. 

I'm not a bass head or a headbanger.  I listen primarily to small ensemble jazz and classical music, but am a firm believer that any high fidelity audio system must be capable of reaching 30-20,000 Hz at live performance levels (105 dB for jazz/classical).  Have separate audio and HT systems in separate rooms.  My audio subs are all 10", one sealed (more of a mid/bass sub) and two are professional ported subs.  And I have ten GIK (found here at AC) absorption panels.  Note that most treatment products aren't worth bringing home.  HT is a low priority for me, in my modest system I have a single 15" sub I bought from a fellow most gracious AC member with no treatment. 

[victorvector]

Thank you again JLM , I should pay more attention , ( just reviewed post #5 )

You have a great way of explaining things , I could easily follow what you just posted ....... things do not always come as easy to me as that brief , concise explanation
 


BTW .......that system in your gallery  looks great , so clean !  ( no clutter !!!! , NICE ! )