And if it didn't have enough force to move the cone at this frequency, would it not show up in the measurements?
Exactly. The cone can move back and forth one thousand times a second no problem, that fact is staring at you in every plot. I thought this was maybe referring to the audiophile voodoo that there are fast and slow bass drivers. I have no idea what that is supposed to mean but I suspect someone might have heard some room mode droning on or whatever and somehow come up with the idea they were hearing a "slow" woofer flopping around.
Last edited:
no i didn't mean a speed of high mass cone driver vs low mass membrane driver (as in woofer vs compression driver) but rather direct radiator vs horn loaded. you simply have two different principles or air-coupling and one of these is dealing with air impedance in a much more efficient manner. i would expect this to be somehow audible - sorry for coming here to a subjective ground but i keep on hearing this in different designs and there's a clear reason why there's a horn loaded bass or mid-bass systems.
unless geddes' waveguides don't behave here like a usual horns - i know he was insisting that the main role of his WG is about directivity not the usual functions of the horns as we know them. maybe this is tackling the issue, i don't know.
i've found this to be a main problem of many speakers whose design is mixing horns and direct radiators (of a kind) - like avantgarde etc - a subjective feeling that bass is somehow lagging behind. i can even slightly hear that in my (small) room with much better design than avantgarde duo.
unless geddes' waveguides don't behave here like a usual horns - i know he was insisting that the main role of his WG is about directivity not the usual functions of the horns as we know them. maybe this is tackling the issue, i don't know.
i've found this to be a main problem of many speakers whose design is mixing horns and direct radiators (of a kind) - like avantgarde etc - a subjective feeling that bass is somehow lagging behind. i can even slightly hear that in my (small) room with much better design than avantgarde duo.
And that would be?
When I listen to Avantgardes, I dislike the bass as well, but its not because "its lagging behind", this is something your mind is telling you, not your ears. My room does not exhibit this problem, but its not because of Waveguides or anything like that. Its the use of multiple subs which creates a much better sense of bass that couples very well with the waveguides.
Yes, its 3rd order, not fourth. Most larger speakers, like the ones that I use, break-up pretty badly once they become non-pistonic. A sharper filter helps this problem. The Abbey was first order LP for a long time, now its third. The extra slope makes for a slightly smoother crossover. The Nathan is still first order and will probably stay that way.
just to confirm this project is now in the final phase. i've used a 2" MDF for the cab and in the end i opted for the bass from the original project so there was no need to adjust the crossover for that. it sounded surprisingly nice from the first moment everything was assembled. there was just some playing with the cab damping in the bass area left and that's it, or it is my brain reminding about different nature of the LF and MF/HF sounds.
the thing i was most surprised with was lack of coloration from the geddes horn. yes, it maybe ain't have the similar feeling of pressurizing the room like tractrix or lecleach do, however that's compensated with much wider sweet spot and lack of beaming. now i better understand the hype about OSWGs.
actually i'm now contemplating about selling the fiberglass waveguides and building the similar from the plywood or MDF, as it would just look nicer in the room.
also at a certain point i will need to upgrade the crossovers with premium parts at the critical positions on the MF/HF filter which is assembled from the cheaper parts, obviously too see how it works.
but it sounds very decent and not too far from my previous horns that were $$$$$.
even my wife who is always a very critical judge gave them a green light soundwise which is an amazing compliment. she's much more critical than me and very often confronts with my tolerance towards some models....the last one she complained about was audio note AN-J. actually the only two ever to get her blessing in our room were oris swing and this one.
thanks anyone who helped.
the thing i was most surprised with was lack of coloration from the geddes horn. yes, it maybe ain't have the similar feeling of pressurizing the room like tractrix or lecleach do, however that's compensated with much wider sweet spot and lack of beaming. now i better understand the hype about OSWGs.
actually i'm now contemplating about selling the fiberglass waveguides and building the similar from the plywood or MDF, as it would just look nicer in the room.
also at a certain point i will need to upgrade the crossovers with premium parts at the critical positions on the MF/HF filter which is assembled from the cheaper parts, obviously too see how it works.
but it sounds very decent and not too far from my previous horns that were $$$$$.
even my wife who is always a very critical judge gave them a green light soundwise which is an amazing compliment. she's much more critical than me and very often confronts with my tolerance towards some models....the last one she complained about was audio note AN-J. actually the only two ever to get her blessing in our room were oris swing and this one.
thanks anyone who helped.
First of all, mass affects efficiency, not necessarily speed; for a given freq and excursion, it will simply take more power.
If the mass is actually in the cone, it may very well play high better; if it's twice as thick, it's 8 times stiffer, allowing it to play higher before breakup modes.
That's other things equal, which they may not be, i.e. inductance.
Looks like Genelec is a fan of Earl Geddes:
Gedlee Abbey, a two way loudspeaker with a 12" woofer and a 1.7" compression driver loaded in an O.S. waveguide
Genelec S360A, a two way loudspeaker with a 10" woofer and a 1.7" compression driver loaded in an O.S. waveguide
Before anyone says "there's lots of speakers just like this out there", note:
1) the Genelec appears to be sealed, which is very unusual. (Gedlee Abbey is sealed.)
2) the Genelec is explicitly designed with a high F3. It's supposed to be mated with a sub array and they raised the F3 to increase the overall output.
Gedlee Abbey, a two way loudspeaker with a 12" woofer and a 1.7" compression driver loaded in an O.S. waveguide
Genelec S360A, a two way loudspeaker with a 10" woofer and a 1.7" compression driver loaded in an O.S. waveguide
Before anyone says "there's lots of speakers just like this out there", note:
1) the Genelec appears to be sealed, which is very unusual. (Gedlee Abbey is sealed.)
2) the Genelec is explicitly designed with a high F3. It's supposed to be mated with a sub array and they raised the F3 to increase the overall output.
Attachments
Last edited:
Some more info, gleaned from the brochure:
1) waveguide is 90° x 60° and is largely elliptical oblate spheroidal, similar to the JBL waveguides from a few years back. It's not *exactly* EOS, because there's a slooooow narrowing of the beamwidth up high, same as JBL does now with their ICW waveguides.
2) Crossover point appears to be 1400Hz, based on the vertical polar response.
3) At first I thought the speaker was sealed, but it's not. The ports are on the bottom.
1) waveguide is 90° x 60° and is largely elliptical oblate spheroidal, similar to the JBL waveguides from a few years back. It's not *exactly* EOS, because there's a slooooow narrowing of the beamwidth up high, same as JBL does now with their ICW waveguides.
2) Crossover point appears to be 1400Hz, based on the vertical polar response.
3) At first I thought the speaker was sealed, but it's not. The ports are on the bottom.
Attachments
Hello.
Good to see an Abbey build thread.
Instead of starting a new one, I think I could just ask my few questions here. I bought a kit back in 2012 and it has languished in a corner of my bedroom ever since. I have the drivers but I need to buy crossover parts. The bass drivers I bought from Thomann, the compression drivers were included with the front panels by Dr. Geddes.
Problem is, I have two crossover schematics for the compression drivers, and I've forgotten which one I should use and could not find that information easily. It was not in the email exchange, but I assume I have seen it either somewhere in this forum or the now defunct forum that Dr. Geddes had.
Both of my DE250-8 have 122201229 written on them.
Good to see an Abbey build thread.
Instead of starting a new one, I think I could just ask my few questions here. I bought a kit back in 2012 and it has languished in a corner of my bedroom ever since. I have the drivers but I need to buy crossover parts. The bass drivers I bought from Thomann, the compression drivers were included with the front panels by Dr. Geddes.
Problem is, I have two crossover schematics for the compression drivers, and I've forgotten which one I should use and could not find that information easily. It was not in the email exchange, but I assume I have seen it either somewhere in this forum or the now defunct forum that Dr. Geddes had.
Both of my DE250-8 have 122201229 written on them.
