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In the Forum: Horn-Loaded Speakers
In the Thread: Eventually - a reasonable midbass horn from GOTO
Post Subject: Six days from the life of GOTO drivers.Posted by Romy the Cat on: 12/12/2007
 Jeffrey Jackson wrote: |
| first, basshorns... the basshorns that I posted here some years back are my straight ~50Hz horns (my memory is fading)... they are 8' long... then rear chamber.. mouth ~ 3' x 4'... throat ~8" x 8"... rear chambers of various sizes and some partially filled with blocks of wood as I tuned resonance... so yes, I also have quite a bit of experience with woofers in midbass horns *with compression* and tuning for optimal results.. measured and listening... I feel that you *must* do both... the one thing that I wish I would have tried was a simple phase plug.. that seems to be the thing that "real" compression drivers have that we don't.. it would be easy.. just turn one from wood... suspend with long screws... of course, this needs to be factored into the horn flare... it adds length, but as we discussed, most midbass horns need more length, not less... and then there is the issue of how much compression.. sigh.. so many variables... |
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This one? http://www.GoodSoundClub.com/TreeItem.aspx?PostID=1301
| Jeffrey Jackson wrote: |
| one place that my findings were different from yours was in field coil drivers in my midbass horn... I found that in my application (Jensen F12N) a stronger field really helped the sound... more clarity in the upper reaches of the horn... I have rationalized this as the stronger field is driving Qes down.... |
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I do not see where you see difference. I do report that higher flux really helps to many things but in the driver upper range. The higher flux also affected the lower range of the driver negatively (over-damping the cone). Here is the key, the no one understands about the field coil – the process of setting up a right flux density for a given frequency range is much different then with magnets. Perm magnets demonstrate much more tolerance to perfect flux-to-frequency balance but electromagnet are way too sensitive to have literalsy half octave of perfect flux-to-frequency “sweat spot”
| Jeffrey Jackson wrote: |
| oh.. and the double driver being "better" than one... I should really retract that statement… |
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I know you would.
| Jeffrey Jackson wrote: |
| so.. now to my new quick and dirty Goto setup... as I began above, I am no longer using my pair of straight basshorns.. I will be constructing something new soon... not sure what just yet.. thinking similar to what I had, but more "wife friendly"... I have moved out of my shop and have to be a bit more domesticated.. but that is a small price to pay to have one of my horn systems in the house again.. ahhh....
so here it is...
JBL 2405 ~7k up
Goto 370 on 600 horn ~1k to 7k
Goto 505 on 150 horn ~220 to 1k
Sealed box 15 ~220 down
(old Pioneer with cast frame, paper cone, and linen surround) |
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Well, the key in all of this installation would be your decision about the type of bass horns you decided to go for. Most likely, looking at the size of the room and considering that your wife most like will not allow you to convert the windows in mouths of the basshorn you will go for upperbass horn. Still, if it will be 80Hz horn for instances then you might review how you cross your GOTO 505 driver. I can see you going up in all your low knee crossover points. (Unless you use high order slopes that GOTO moronically recommend). BTW, looking at the picture it is a clear self-evident my objections to the negative opening of that French profile – it doe very nice at HF but at the horn that rolls of at 1000Hz the negative opening is just a waste of so valuable vertical space.
| Jeffrey Jackson wrote: |
| at the moment I am biamping with speaker level crossovers.. Eimac 75tl on horns and SE845 on woofers... I have so many "next steps", but likely next will be to line level cross... I *know* how much better line level crossovers are.. every time they astound me... |
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This is a complicated subject all together and it’s alone might des own thread. The line level crossovers, although they over unquestionably a lot of multifaceted advantages, might be quite complicated and ambiguous thing to do properly. I spent 2 month with the line level crossover for my 6-chennal Super Milq…
http://www.goodsoundclub.com/GetPost.aspx?PostID=5780
| Jeffrey Jackson wrote: |
| then new horns for Goto drivers.. |
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Jeffrey, what I am interning in this project is your feeling about the Goto drivers. I understand that they are exotic, expensive and “hard to get” but are any more serious rational made you it use them. I do not know you but looking that you have expressed quite rational attitude toward to some other subjects of horn I presume that you are not novice and therefore you most likely went over a number of different compression drivers. So, if to drop the preoccupation with brands then what you feel GOTO sound like. Let for sake of ability to communicate to compare the sound of GOTO with sound that I consider as a default compression driver: JBL 375/2440. I have some concerns about GOTOs design (at least what I know about it) but I never took GOTO driver apart and learn how it made – with that all my concerns worth a little. No one publish a deals diagraph or image of the driver’s guts. So, let talk about the GOTO sound. Is any specific sonic attribute that attracts you to GOTO drivers? Also, how do you cross them (slope) and what it you feeling about the driver’s sound in near-crossed regions. I NEVER EVER heard anyone actually to talk or write intelligently about the Sound of GOTO drivers. What I head was juts “eyes blinking” and the idiotic comments about “music” when the conversation should be about explicit Audio applications.
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