Banned
Joined 2002
AJinFLA said:Hi Simon,
I don't recall what they sounded like before the mods, since the sole purpose of buying them was for the unique cabinets. The drive units are not state of the art by any means, but are not junk either. The tweeter actually measured ruler flat (on axis), as flat if not flatter than the XT! Modified they actually sounded pretty good. I started with a D25AG35 back in '99, then changed to the XT as soon as it was available for DIY. On good recordings they would essentialy "disappear" the way a good speaker should. The XT-25 has a unique sound (if you have ever heard it) - very clear/clean, etc. There is a reason why it's used in so many designs. It's response plummets off-axis however. The rear tweeter was an attempt to even the power response, as well as add just a little "sparkle" to the high end. Placement out into the room was a must. But that forced me to use a higher XO to my sub than I would have preffered, since even though it has decent bass output, it's still a 5" driver. If you can pick up a pair in England for cheap, it might make for a fun project. Unfortunately that was my last "box". There's no going back now after these
You should post a picture of the whole system buy the looks of the room at that angle it should look awesome.
BG linesource homebrew
Just completed these BG-75's as a dipole linesource, with Peerless HDS
mid-woofers for 600 Hz to 50 Hz range, Peerless tweeters (one firing forward, one backwards) from 3500Hz up, EAS-400 leaf-tweeter as super tweeter from 7000Hz up. The bottom end is augmented by a Titanic 12" sub in a 5 ft^3 sonotube, pretty much from 100 Hz to < 20 Hz.
The imaging is pretty dramatic, and the detail in the music is about the best I've heard in over 35 years of building and listening to loudspeakers. The baffles are handcut solid cherry 1" thick, the mid-woofer enclosures are 1" MDF.
Rough measurements are very smooth throughout the range 400 Hz - 16KHz, with SPL for system measuring > 107dB at 12 feet. (Everyone runs if I try to go higher)
Just completed these BG-75's as a dipole linesource, with Peerless HDS
mid-woofers for 600 Hz to 50 Hz range, Peerless tweeters (one firing forward, one backwards) from 3500Hz up, EAS-400 leaf-tweeter as super tweeter from 7000Hz up. The bottom end is augmented by a Titanic 12" sub in a 5 ft^3 sonotube, pretty much from 100 Hz to < 20 Hz.
The imaging is pretty dramatic, and the detail in the music is about the best I've heard in over 35 years of building and listening to loudspeakers. The baffles are handcut solid cherry 1" thick, the mid-woofer enclosures are 1" MDF.
Rough measurements are very smooth throughout the range 400 Hz - 16KHz, with SPL for system measuring > 107dB at 12 feet. (Everyone runs if I try to go higher)
Attachments
Coherency ??
Interesting you should ask. I originally thought about line sourcing with multiple tweeters (hence the extra baffle space) or additional mid woofers (still could be added if need be), but to keep the cost resonable, and being of the KISS (keep it simple stupid) mentality, I tried to minimize the drivers yet meet the power requirements.
The BG's are ~88 dB or so efficient; I initially connected the peerless tweeters in parallel facing forward ---> way too efficient for the BG's and suffered pretty severe comb-lobing within a few feet of the baffle.
Switching them to series connection reduced the output to compatible with the BG's, but comb effects still prevailed. I then reversed the top tweeter, connected out of phase (in phase with the BG's rear radiation), added Zobel networks on the drivers, added baffle step compensation @ ~220 Hz, added BG notch filter @ ~5500 Hz. (see attached photo of xover components not yet mounted)
The resultant sound is pretty seamless. My idea was to maximize the impact of the BG's , using the mid woofers to take over ~600 hz and down. They also are connected in series rather than parallel to better match the BG's sensitivity, and are mounted in a box tuned to ~50 Hz. The series connectiion is a much easier load to drive at high levels.
The front firing EAS 400 super-tweeter is a leaf type with minimal vertical dispersion, and curiously seems to have little audible interference with the peerless dome tweeter, maybe due to the much higher xover. The 45 degree swept wings help with rear wave directivity and seem to improve the general open dipole sound with wide and deep soundstage.
Interesting you should ask. I originally thought about line sourcing with multiple tweeters (hence the extra baffle space) or additional mid woofers (still could be added if need be), but to keep the cost resonable, and being of the KISS (keep it simple stupid) mentality, I tried to minimize the drivers yet meet the power requirements.
The BG's are ~88 dB or so efficient; I initially connected the peerless tweeters in parallel facing forward ---> way too efficient for the BG's and suffered pretty severe comb-lobing within a few feet of the baffle.
Switching them to series connection reduced the output to compatible with the BG's, but comb effects still prevailed. I then reversed the top tweeter, connected out of phase (in phase with the BG's rear radiation), added Zobel networks on the drivers, added baffle step compensation @ ~220 Hz, added BG notch filter @ ~5500 Hz. (see attached photo of xover components not yet mounted)
The resultant sound is pretty seamless. My idea was to maximize the impact of the BG's , using the mid woofers to take over ~600 hz and down. They also are connected in series rather than parallel to better match the BG's sensitivity, and are mounted in a box tuned to ~50 Hz. The series connectiion is a much easier load to drive at high levels.
The front firing EAS 400 super-tweeter is a leaf type with minimal vertical dispersion, and curiously seems to have little audible interference with the peerless dome tweeter, maybe due to the much higher xover. The 45 degree swept wings help with rear wave directivity and seem to improve the general open dipole sound with wide and deep soundstage.
Attachments
Well finished both my speakers, very pleased with how they sound considering this was my first try.
http://gmd.shackspace.com/Speakers/SpeakersAmp.jpg
http://gmd.shackspace.com/Speakers/SpeakersAmp.jpg
maxw said:
Nice
Was that a kit? or did you make and finish the enclosure your self?
The enclosure is the 1 ft^3 MTM prefinished enclosure from partsexpress with the removable front baffle in case you mess up cutting your holes. I really didn't have the time to make my own but the partsexpress model is extremely well made and the finish is flawless. Everything else was of my design (driver selection, crossover, etc)
Gmd said:
That is the EL84 one isn't it? That would be my choice of all their amps. I have a modded EL34 one here now (Chris'). It will eventually get a complete rebuild... probably become an Allen Wright/Vacuum State style diff amp.
dave
Think I'll call 'em "Quartz I"... <G>
>Those look impressive... any non-coherency issues with the transitions from point source to line source & back again?
...because their shape looks like a quartz crystal... and they sound sooo clear...
I'm continuing to be amazed at the clarity and revelatory experience listening to prior music again with these speakers. I just listened to Eric Marienthal's "One Touch" CD, and the piano solo ~01:40 into the last cut (#10 "Where Are You") has one of the first truly believable images I've heard. It's like listening to a grand playing 12 feet away... with the pianist sitting facing towards the rear wall... the lower registers are to the left ~ 1/3 left of center... upper registers are to the right ~ 1/3 left of center.. and arpeggios and runs move back and forth correctly and convincingly with proper depth and soundstage. Makes me want to re-listen to my entire 600+ cd collection... not to mention the 1000's of hours of open reel tapes I've accunulated over the last 4 decades...
I guess that's what makes these projects so worthwhile... kinda like a search for the holy grail.
>Those look impressive... any non-coherency issues with the transitions from point source to line source & back again?
...because their shape looks like a quartz crystal... and they sound sooo clear...
I'm continuing to be amazed at the clarity and revelatory experience listening to prior music again with these speakers. I just listened to Eric Marienthal's "One Touch" CD, and the piano solo ~01:40 into the last cut (#10 "Where Are You") has one of the first truly believable images I've heard. It's like listening to a grand playing 12 feet away... with the pianist sitting facing towards the rear wall... the lower registers are to the left ~ 1/3 left of center... upper registers are to the right ~ 1/3 left of center.. and arpeggios and runs move back and forth correctly and convincingly with proper depth and soundstage. Makes me want to re-listen to my entire 600+ cd collection... not to mention the 1000's of hours of open reel tapes I've accunulated over the last 4 decades...
I guess that's what makes these projects so worthwhile... kinda like a search for the holy grail.
amp design
gday!
it's not loudspeaker, but it's can be close
common concept. usualy I made marble subwoofers and even full range system by marble.
now I want to show my first amplifier with marble front panel.
more detail - there http://www.artmaydan.org.ua/amp.html
gday!
it's not loudspeaker, but it's can be close
common concept. usualy I made marble subwoofers and even full range system by marble.
now I want to show my first amplifier with marble front panel.
more detail - there http://www.artmaydan.org.ua/amp.html
Attachments
SimontY said:
Not everyone can hear a difference from one chassis to another, microphonics, electromagnetics and all other forms of interference combined. Not everyone thinks it's an issue at all... And not everyone has speakers that might highlight it as an issue.
But yes, it does look nice.
thank you gentlemen!
that's right. marble front doesn't sound better, or not.
but I asked my customer about amp design and we get agreement - let it be the same like loudspeakers.
that amp is not simple inside. it has a few new idea from master - Samod. you'll be able to find him in the amplifier forum there.
that's right. marble front doesn't sound better, or not.
but I asked my customer about amp design and we get agreement - let it be the same like loudspeakers.
that amp is not simple inside. it has a few new idea from master - Samod. you'll be able to find him in the amplifier forum there.
stored energy??
> Doesn't it cause problems with the sonics though? (stored energy, microphonics resulting in a thuddy unprecise sound)
What would be the source of the "stored energy" in the marble that would degrade the sound? All matter above absolute zero has "stored energy" in the form of lattice vibrations, etc. that on an atomic level are orders of magnitude greater than anything imposed from a macroscopic external source (such as vibrations thru the chasis) Or do you mean that somehow electonic noise is being imposed by the marble front?
Older tube gear sometimes suffered microphonics when the filaments physiaclly vibrated and changed the mechanical properties of the tube design. Is this what you mean? if so, the marble would help prevent this, not cause it.
This is the stuff of urban myth promulgated by "high end" mfgs. of "single xtal directional wires", "intergranular diodes", "skati stones & tice clocks" etc. and other such nonsense.
> Doesn't it cause problems with the sonics though? (stored energy, microphonics resulting in a thuddy unprecise sound)
What would be the source of the "stored energy" in the marble that would degrade the sound? All matter above absolute zero has "stored energy" in the form of lattice vibrations, etc. that on an atomic level are orders of magnitude greater than anything imposed from a macroscopic external source (such as vibrations thru the chasis) Or do you mean that somehow electonic noise is being imposed by the marble front?
Older tube gear sometimes suffered microphonics when the filaments physiaclly vibrated and changed the mechanical properties of the tube design. Is this what you mean? if so, the marble would help prevent this, not cause it.
This is the stuff of urban myth promulgated by "high end" mfgs. of "single xtal directional wires", "intergranular diodes", "skati stones & tice clocks" etc. and other such nonsense.