pharoahra said:
Thank you, that was my thought as well that it makes little difference. Since I'm new to OB designs, I was wondering if Vas affects the surface area of the baffle at all. My guess is no.
-David
hifimaker said:
well please dont take my response as an answer to your question.i am very new to ob designs to.i was simply stating i dont know.
>>> Can I go to Martin's house and listen?
I'd love to go to Martin's house and listen but now i don't have too. I built my own H frames using Alpha 15s and hooked them up this afternoon a few hours before the Super Bowl.
Thanks Martin! Excellent project with great results.
Godzilla
I'd love to go to Martin's house and listen but now i don't have too. I built my own H frames using Alpha 15s and hooked them up this afternoon a few hours before the Super Bowl.
Thanks Martin! Excellent project with great results.
Godzilla
The photo shows exposed messy wires but i was excited to hear the H-Frames. Basically i have been unhappy with the sealed subwoofer (black box) for quite a while now. It never integrated with the BIBs and always sounded disconnected and somehow 'thick' in the bass. I would slide it around into different places but it pretty much sounded the same. It's a nice ACI SV12 in a 2.5L sealed box. I've had it for several years. The plan is to replace this sub with something better. The H-Frames certainly offer more guttural impact, dynamics and loudness. They do not sound thick or slow but i still have not dialed them in 'just right' yet. Their potential is awesome! I keep reducing the crossover and lowering the volume knob because they have the ability to scare you out of the room. Based on initial listening i do believe they can recreate the sound of a real live airplane landing in my basement! I did have a great listening session with them yesterday and know know all i have to do is fiddle a bit more. The variable crossover is set to around 70hz (needs to be lower) and the volume knob is maybe up an eighth. There is more detail to the bass and a room filling ease compared to the 12 inch sealed... there really is no comparison. The H-Frames offer much more bass output, they just need to be tamed.
I am excited to find the right amount of tweak to make these things work in my room with my BIBs. Room placement was not an issue. I thought it would be from reading Martin's paper... but they always pumped out plenty of output even when closer to the rear wall. In the pic they are about three feet out.
Godzilla
I am excited to find the right amount of tweak to make these things work in my room with my BIBs. Room placement was not an issue. I thought it would be from reading Martin's paper... but they always pumped out plenty of output even when closer to the rear wall. In the pic they are about three feet out.
Godzilla
Attachments
Godzilla,
Very nice, an Alpha 15A in an H frame is a very interesting combo. A high Qts driver in an H frame provides a surprising amount of bass in both depth and quality. I bet they sound great.
Does this mean you are not stopping by for an afternoon of listening and speaker discussion next time you are up north?
Very nice, an Alpha 15A in an H frame is a very interesting combo. A high Qts driver in an H frame provides a surprising amount of bass in both depth and quality. I bet they sound great.
Does this mean you are not stopping by for an afternoon of listening and speaker discussion next time you are up north?
BIB augmentation
I may open a new thread to discuss using OB as bass extension for BIBs.
TIA,
Godzilla [/B][/QUOTE]
Godzilla,
I am getting ready to start a BIB project (w/AN Cast Frame Super 8) and wondering if you ever opened the thread mentioned above?
MJ
I may open a new thread to discuss using OB as bass extension for BIBs.
TIA,
Godzilla [/B][/QUOTE]
Godzilla,
I am getting ready to start a BIB project (w/AN Cast Frame Super 8) and wondering if you ever opened the thread mentioned above?
MJ
>>> I am getting ready to start a BIB project (w/AN Cast Frame Super 8) and wondering if you ever opened the thread mentioned above?
Feel free to start a thread for enhancing BIB bass. I have not. Even tho BIBs allow our beloved full/wide range drivers to reach down low some of us may want even more bass. Because BIBs are fast and dynamic sounding speakers they really need more than slow, heavy bass drivers to keep up without sounding disconnected. I've been told BIBs using 8 inch drivers rattle the windows... that's fine but added flexibility will further improve their sound.
>>> I bet they sound great.
>>> Does this mean you are not stopping by for an afternoon of listening and speaker discussion next time you are up north?
They do sound GREAT Martin! (I will let you know when i am in your area. Lunch will be my treat) I was surprised actually because i did not believe open back 'anything' was going to reach down low like this. I guess it's in the science! Thanks for scoping it out and bringing it to our attention.
Based on what i am hearing i believe H-Frames with large, hi Q drivers go beyond what is possible from sealed or ported, slow subs audiophiles currently enjoy at home from REL, Velodyne, etc... as well as bettering multi thousand dollar designs from Focal, Dynaudio, etc. We have moved into Pro Sound with style. These H-Frames offer very high quality, detailed bass that's better than anything i've ever heard to date. And to think doubling up two per side would sound even better. Maybe my room is too small for that but knowing there is an upgrade path is always nice.
*******' awesome bass! Now i've got to 'enhance' the treble.
Godzilla
Feel free to start a thread for enhancing BIB bass. I have not. Even tho BIBs allow our beloved full/wide range drivers to reach down low some of us may want even more bass. Because BIBs are fast and dynamic sounding speakers they really need more than slow, heavy bass drivers to keep up without sounding disconnected. I've been told BIBs using 8 inch drivers rattle the windows... that's fine but added flexibility will further improve their sound.
>>> I bet they sound great.
>>> Does this mean you are not stopping by for an afternoon of listening and speaker discussion next time you are up north?
They do sound GREAT Martin! (I will let you know when i am in your area. Lunch will be my treat) I was surprised actually because i did not believe open back 'anything' was going to reach down low like this. I guess it's in the science! Thanks for scoping it out and bringing it to our attention.
Based on what i am hearing i believe H-Frames with large, hi Q drivers go beyond what is possible from sealed or ported, slow subs audiophiles currently enjoy at home from REL, Velodyne, etc... as well as bettering multi thousand dollar designs from Focal, Dynaudio, etc. We have moved into Pro Sound with style. These H-Frames offer very high quality, detailed bass that's better than anything i've ever heard to date. And to think doubling up two per side would sound even better. Maybe my room is too small for that but knowing there is an upgrade path is always nice.
*******' awesome bass! Now i've got to 'enhance' the treble.
Godzilla
Godzilla said:
It is really amazing how inexpensive, how compact, and how easy the high Qts driver H frame is to build and then the depth of bass it can produce. It is almost too simple to be believed.
passive crossower for F120A
Martin,
Have you made any progress with the passive crossover for the F120A driver?
Thanks,
Igor
MJK said:
Martin,
Have you made any progress with the passive crossover for the F120A driver?
Thanks,
Igor
Hi Igor,
Yes, I have made a lot of progress. For the Fostex F120A I am using the following crossover components.
High Pass for F120A
C1 = 43 uF ERSE 250V ($10.46)
L2 = 10 mH ERSE Super Q 16 AWG ($22.96)
The crossover for the Goldwood H frame stays the same for the Jordan and the Fostex drivers.
I have a second set of identical OBs built so I can swap the Jordan and the Fostex very quickly. In my opinion they both have slightly different strengths so it would be a matter of personal taste determining which one is better.
I have also spent some time doing a series of in room measurements at 1 m and at my listening position and have compared them to my latest MathCad worksheet's in room SPL response calculations. The correlations are very good. I have started writing a follow up article for this design covering both of these drivers and the measurement/calculation correlations and should upload it towards the end of this month.
Yes, I have made a lot of progress. For the Fostex F120A I am using the following crossover components.
High Pass for F120A
C1 = 43 uF ERSE 250V ($10.46)
L2 = 10 mH ERSE Super Q 16 AWG ($22.96)
The crossover for the Goldwood H frame stays the same for the Jordan and the Fostex drivers.
I have a second set of identical OBs built so I can swap the Jordan and the Fostex very quickly. In my opinion they both have slightly different strengths so it would be a matter of personal taste determining which one is better.
I have also spent some time doing a series of in room measurements at 1 m and at my listening position and have compared them to my latest MathCad worksheet's in room SPL response calculations. The correlations are very good. I have started writing a follow up article for this design covering both of these drivers and the measurement/calculation correlations and should upload it towards the end of this month.
Please could we have a circuit diagram of the high and low pass filters for those of us who are dummies?
TIA.
TIA.
A circuit diagram and pictures of the crossovers are in the write-up. Every time I try and add a picture to a post I get all hosed up. They are just classic second order filters so a text like the LSDC will have an adequate diagram.
I have also built an OB using the Alpha 15A in an H-Frame. To drive the Alpha's I am using a high level inputs to a 70 watt PE plate amp that has variable 2nd order crossover to 200 hz. I currently have it set to somewhere around 150 hz with the gain set a little over half way to blend in with the EV's on top.
The top baffle is a U-Frame with an overall depth as measured from the front of 5". The centerline of the Electrovoice SP12B wideband driver is about 34" off the floor with a passive 2nd order high pass at 200 Hz. This is more or less the same configuration that Martin outlined for the Jordan/Goldwood project. To fill in the high end I am using a Fostex T90A supertweeter with L-Pad with a first order high pass at 7500 Hz (2.7 uf cap). The top baffle is loose and can be move around to suit.
Both the H-Frame and top baffle are made using Baltic Birch.
http://gallery.me.com/marilynladieu#100295
I spent a lot of time using Martin's worksheets to model this set-up and I am very pleased with the outcome. They are every bit the equal of my Fostex FE166-ES-R Factory Recommended BLHs. The bass is wonderful, visceral, and very detailed. When listening to an up-right bass it feels as though he is right in the room. The mid range off the EV's are a delight, very detailed without being harsh. They are well broken in as I have been using them pretty much everyday for the past 34 years. '😀' My wife initially objected to them but after listening for the past couple weeks her objections have waned.
Work that needs to done to finish them off: clean-up and build a box for the plate amp and crossover components; play with a series inductor on the EV to clean up small amount of upper mid grunge; get a hold of some stone to add mass to the top of the H-Frame; and complete the finish.
Many thanks to Martin for the inspiration for this project.
Bill
The top baffle is a U-Frame with an overall depth as measured from the front of 5". The centerline of the Electrovoice SP12B wideband driver is about 34" off the floor with a passive 2nd order high pass at 200 Hz. This is more or less the same configuration that Martin outlined for the Jordan/Goldwood project. To fill in the high end I am using a Fostex T90A supertweeter with L-Pad with a first order high pass at 7500 Hz (2.7 uf cap). The top baffle is loose and can be move around to suit.
Both the H-Frame and top baffle are made using Baltic Birch.
http://gallery.me.com/marilynladieu#100295
I spent a lot of time using Martin's worksheets to model this set-up and I am very pleased with the outcome. They are every bit the equal of my Fostex FE166-ES-R Factory Recommended BLHs. The bass is wonderful, visceral, and very detailed. When listening to an up-right bass it feels as though he is right in the room. The mid range off the EV's are a delight, very detailed without being harsh. They are well broken in as I have been using them pretty much everyday for the past 34 years. '😀' My wife initially objected to them but after listening for the past couple weeks her objections have waned.
Work that needs to done to finish them off: clean-up and build a box for the plate amp and crossover components; play with a series inductor on the EV to clean up small amount of upper mid grunge; get a hold of some stone to add mass to the top of the H-Frame; and complete the finish.
Many thanks to Martin for the inspiration for this project.
Bill
I like what you have done there Badwater! I was looking at different drivers considering something for an OB as an experiment. Looked at the Eminence Lil Buddy... but i do not like what happens at the top of its range... otherwise it looks like a great OB driver to sit on top of the H-Frames. The look you have is very nice.
>>> The bass is wonderful, visceral, and very detailed. When listening to an up-right bass it feels as though he is right in the room.
I disappeared for about two hours this evening and went thru a bunch of cds to dial in and evaluate. The H-Frames are amazing! The bass on the Wicked cd was always week but not with the H-Frames... it's punchy and full. Bass is really fleshed out and you really can hear details in the bass that really create the illusion of a live performance. There is a 'jump factor' that just is not there with a more 'normal' subwoofer. The H-Frames are a real treat.
Sade's Lover's Rock CD will blow you out of the room if you so desire. I had to lower the volume on this cd because the bass is so over ripe. At more reasonable volumes the bass was rich and deep.
Martin, if you've read this far, I was considering building two 4 cubic foot ported boxes using pro sound woofers before building your H-Frame design. I am so happy to have built your smaller, lighter, easier to build design. They are excellent sounding and fit my space much better! Is it possible the H-Frames go deeper than ported boxes using the Alpha 15s? This seems strange since the drivers Fs is 46hz. Why and how can the H-Frames produce lower bass than that spec?
>>> play with a series inductor on the EV to clean up small amount of upper mid grunge...
Badwater, have you considered using an equalizer to get the sound you want rather than playing with the crossover components? Is this taboo? My old EQ used to kill the life of the sound but that was many years ago. I was wondering if they are more transparent nowadays.
TIA!
Godzilla
>>> The bass is wonderful, visceral, and very detailed. When listening to an up-right bass it feels as though he is right in the room.
I disappeared for about two hours this evening and went thru a bunch of cds to dial in and evaluate. The H-Frames are amazing! The bass on the Wicked cd was always week but not with the H-Frames... it's punchy and full. Bass is really fleshed out and you really can hear details in the bass that really create the illusion of a live performance. There is a 'jump factor' that just is not there with a more 'normal' subwoofer. The H-Frames are a real treat.
Sade's Lover's Rock CD will blow you out of the room if you so desire. I had to lower the volume on this cd because the bass is so over ripe. At more reasonable volumes the bass was rich and deep.
Martin, if you've read this far, I was considering building two 4 cubic foot ported boxes using pro sound woofers before building your H-Frame design. I am so happy to have built your smaller, lighter, easier to build design. They are excellent sounding and fit my space much better! Is it possible the H-Frames go deeper than ported boxes using the Alpha 15s? This seems strange since the drivers Fs is 46hz. Why and how can the H-Frames produce lower bass than that spec?
>>> play with a series inductor on the EV to clean up small amount of upper mid grunge...
Badwater, have you considered using an equalizer to get the sound you want rather than playing with the crossover components? Is this taboo? My old EQ used to kill the life of the sound but that was many years ago. I was wondering if they are more transparent nowadays.
TIA!
Godzilla
Thanks,
I am currently using an SS integrated amp (Onkyo A-9555, very nice amp well worth a look) which doesn't really allow me to play with an equalizer/electronic crossover. As a practical matter the electronics are upstairs in the loft and speakers are downstairs. I am using in house wiring. Bringing the electronics downstairs is no no with my wife. Also, when I used my tripped out Dynaco PAS/ST70 combo to drive the system the plate amp picked up some hum (normally not noticeable) from the ST70 that was very annoying.
I have the inductors and want to experiment and learn. i may decide to do nothing as they sound very good as is.
I know what you mean about the bass. Listening to Loreena Mckinnett, Nights from the Alhambra, I kept having to turn the bass down to tone it down. It was wonderful, but overpowering. It took me couple weeks to dial it in.
Bill
I am currently using an SS integrated amp (Onkyo A-9555, very nice amp well worth a look) which doesn't really allow me to play with an equalizer/electronic crossover. As a practical matter the electronics are upstairs in the loft and speakers are downstairs. I am using in house wiring. Bringing the electronics downstairs is no no with my wife. Also, when I used my tripped out Dynaco PAS/ST70 combo to drive the system the plate amp picked up some hum (normally not noticeable) from the ST70 that was very annoying.
I have the inductors and want to experiment and learn. i may decide to do nothing as they sound very good as is.
I know what you mean about the bass. Listening to Loreena Mckinnett, Nights from the Alhambra, I kept having to turn the bass down to tone it down. It was wonderful, but overpowering. It took me couple weeks to dial it in.
Bill
Godzilla said:
I think there are a couple of things that contribute to the low end performance of the Alpha 15A in an H frame.
1) I measured the fs of my four Alpha 15A drivers to be an average of 41 Hz. When you put them in the H frame the air in the frame loads more mass onto the driver's cone. Theoretically, I calculate a new fs value of 31 Hz. I don't think it gets all the way down to 31 Hz, probably an fs closer to 35 Hz with an f3 of about 30 Hz,
2) The big driver moves a lot of air by displacing just a little distance, I think this helps with the bass transients. I found my Goldwood 18" drivers don't move very much in the H frame even with the 1812 overture. How much are the Alpha 15A's moving on heavy bass music? The Goldwoods are a few inches bigger but you pick up almost another 10 Hz of bass extension.
Big driver with a Qts that is appropriate for dipole operation, it is different from the smaller low Qts driver approach where you apply lots of EQ/power trying to force bass fomr a dipole. I love the small and easy build, it will have to be a very special design for me to consider building another big box. The concept seems counter intuitive and to primative, but in my opinion it works really well.
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