In reference to:

http://www.goodsoundclub.com/TreeItem.aspx?PostID=1414

I had recently a guy in my listening room and he asked me if it would be possible to get the 300Hz range in the way how it sounds in my room but without using those larger upper bass horns.

I was laughing and replayed that THAT was what the whole game all about. I do not know any ways to reduce upper-bass, or what Clark called “the melody range”, properly besides a straight radiation horn with a small throat when the horn do not load as a direct radiator even an octave or two before the “the melody range”. Still…, the narrow throated, straight, upper-bass is a big and in many instances not manageable. So, if anything out there could compete with what a horns does with upper bass? Let pretend that the horn loading does not exist, then what would be the next in succession line?

Ironically, among all enclosures and topologies that I have heard I found that a properly done bass-reflex enclosures can do the  “the melody range” quite adequately. What, the ported speakers? Are you out of your mind, Romy? This what you are proposing after the years of bitching about the “ported sound”? Yes, I do. Here is what I mean….

If a port is properly implemented then the port might do a phenomenally good upper-bass, almost as good as a “horn-loaded” upper-bass horn. The problem is that NO ONE uses the ported design properly. If do not let the ported design to go all the way down and to cut off the channel very slightly lower then the port begin to EQ the bass then it is possible to get a very-very good Sound using the bass-reflex enclosure. Paradoxically the driver in this case should be not really “ported” and an extra one or two LF channels would be mandatory for the lower octaves but with all those incontinences we gain “quality” of sound… using a port. A typical cut off of a bass-reflex enclosure in order to work properly should be somewhere around 110Hz-180 Hz and it done so then the “ported sound” does not manifest itself at all. Quite in contrary, the properly done bass-reflex might be very live, very dynamic and very musical.  Listen for instance the Wilson Alexandria’s high- passed upper bass – it absolutely extraordinary but let the speaker run full-range and the Alexandria’s ported lower and mid-bass will screw everything up. The only one problem that I can see with properly done port channels that they are effective only in a VERY narrow bandwidth. Bring frequencies too low and the noise form the port compromises the entire “melody range”. Bring it too high that the driver being to sound like an open baffle….

I did not see anyone even tried to do what I proposed above commercially. There was an old model of Kharma Audiocratique that had two bass sections; one of them was sealed another was ported:

The Kharma sentiment was correct but it unfortunately was not done properly: the ported channel went too low and the sealed channel was too week – a wrong driver and not enough volume of enclosure. Still it is the only one known to me commercial attempt to deal with the ported upper bass in more sensible way then it done usually.

Rgs,
Romy the Cat

Mats,

Actually I do not exactly understand what you are trying to accomplish. The Altec midrange after 4uF will roll at 3.5kHz-5.0kHz, depending of the type of coil you use. If you cut the MF channel so high then I would ask why you do so and why you in this case use so deep horn for the Altec?  I personally can see in you installation two extra channels that I can’t figure out what they do. You might eliminate for this setup two horns and you will have multiple benefits if you do so. BTW, the eliminate of the horizontal bias between the drivers will be quite important one…

Rgs,
Romy the Cat

Romy the Cat wrote:

Try to drop the Altec in 400Hz horn down to 1000 Hz -700Hz and arm your Oris with a MD driver with a good lover midrange driver (B&C of whatever you use) You will be able to go away with 4 channels… You have a lot of nice horns… It should be fan to play with them…. The Cat

Mats, I do not know who is Jeffrey is, anyhow, your horns look nicer this time. You need to figure out now what would sound more interesting: the 8PS21 at its higher knee or the Altec at it’s lower knee. The important would be that beside thier absolute quality of sound the both drivers should have the same tonal, dynamic and the same tension characteristics after own crossover points. Use the “vertical split” techniques that I’ve descried early on somewhere within my site to mach the channels. It would be also beneficial if you reduce the size of the Altec horn to the minimum permeated by the found crossover point of the driver (usually 60% or wherever the honk despairs). Generally the 804 is quite mellow and none-demanding driver and you should not have any problems to integrate is with anything….

Rgs,
The Cat

Romy the Cat wrote:

Mats, I do not know who is Jeffrey is, Rgs, The Cat

Jeffrey as in Jeffrey Jackson:

http://www.goodsoundclub.com/TreeItem.aspx?postID=1301#1301

I’m new to this outstanding website and I found it has really educational value and antimoronizating information

I’m still in the world of direct radiators and I’m looking for the ultimate midbass channel solution. At this time it’s still impossible to build a horn of this size so my purpose is to find the next most good sounding solution. Some time ago I found very appropriate driver for upperbass reproduction – ScanSpeak 18W/8535. It has smaller magnet system (and little lower efficiency) compared to 8545. The cone material is the same as the famous 25W/8565-00 bass drivers and it has very good tone up to 600-650Hz. But then I read this:

Romy  the Cat wrote:

Ironically, among all enclosures and topologies that I have heard I found that a properly done bass-reflex enclosures can do the  “the melody range” quite adequately. What, the ported speakers? Are you out of your mind, Romy? This what you are proposing after the years of bitching about the “ported sound”? Yes, I do. Here is what I mean…. If a port is properly implemented then the port might do a phenomenally good upper-bass, almost as good as a “horn-loaded” upper-bass horn. The problem is that NO ONE uses the ported design properly. If do not let the ported design to go all the way down and to cut off the channel very slightly lower then the port begin to EQ the bass then it is possible to get a very-very good Sound using the bass-reflex enclosure. Paradoxically the driver in this case should be not really “ported” and an extra one or two LF channels would be mandatory for the lower octaves but with all those incontinences we gain “quality” of sound… using a port. A typical cut off of a bass-reflex enclosure in order to work properly should be somewhere around 110Hz-180 Hz and it done so then the “ported sound” does not manifest itself at all. Quite in contrary, the properly done bass-reflex might be very live, very dynamic and very musical.

It’s a quite interesting idea and I’m going to try this type of midbass loading very soon with SS 18W/8531 driver I don’t own yet.

Romy the Cat wrote:

The only one problem that I can see with properly done port channels that they are effective only in a VERY narrow bandwidth. Bring frequencies too low and the noise form the port compromises the entire “melody range”. Bring it too high that the driver being to sound like an open baffle….

I absolute agree with that statement! I made experimental enclosure for SS 18W/8545 tuned to 36Hz line high passed at 140Hz first order. The problem is that it sounded like open baffle even filtered at 300Hz…. And still it’d just one octave operation bandwith. If I lower the upper frequency point to 220Hz this effect evaporate but effective radiation is only 140-220Hz and it sounds like a little peak in the frequency response.

But later you said

Romy  the Cat wrote:

“Commandments of Mandatory Middbas Compliance”: 1) A middbas driver shell handle at least one octave below it lower cut off frequency 2) A dipoleness shell not be used anywhere near a middbas channel The next candidate for middbas reproduction would be all versions of the box-reflex design.  Everything in ported sound is wonderful accept the fact that the ported enclosures kill all sound under 700Hz -800Hz. The third rule of “Commandments of Mandatory Middbas Compliance” said: 3) You shell run away from a speaker if you see a port

haralanov wrote:

I’m still in the world of direct radiators and I’m looking for the ultimate midbass channel solution. At this time it’s still impossible to build a horn of this size so my purpose is to find the next most good sounding solution. Some time ago I found very appropriate driver for upperbass reproduction – ScanSpeak 18W/8535. It has smaller magnet system (and little lower efficiency) compared to 8545. The cone material is the same as the famous 25W/8565-00 bass drivers and it has very good tone up to 600-650Hz.

haralanov wrote:

Romy, is there something you have found about ported enclosures and rejected the idea above?

Being +/- resigned to using BR myself right now, I concur with the idea of "not using" the bin and/or port for significant gain, and especially not to push a driver down to Fs.

I don't know the driver being referred to here, but I would recommend taking another look at whether you want 650 Hz or, say, 40 Hz, because I seriously doubt you can get that sort of range with harmonic and/or dynamic continuity.  Basically, the bin/port will affect the character of the sound differently as frequency rises.

I chose to go low-ish and wound up using very thick plywood and I coated the inside of the bins with acrylic-modified stone veneer mortar as part of my efforts to get the box out of the sonic equation.  I tried using felt inside and wound up with alternate inside faces only felted.  The port came out very close to the computer simulations, but any variation is ultimately audible.


Best regards,
Paul S