Hi Erik,
Here's a screen cap of the Neo10 shelf in the DLCP editor:
I didn't use a plain shelf but tried to combine the dipole correction and the first half of a 24dB/oct LR filter by using an asymmetric shelf (Linkwitz transform). I arrived at these settings by playing around with the zero pole parameters. I used the same approach for the ribbon, here are the normal response curve for the Neo and ribbon and the curve with the tweeter phase inverted:
This was an earlier test with a lower cutoff for the ribbon. I think this shows that this approach is working.
regards,
Gerrit
Hi Gerrit,
I completed my speakers, I dare to say the look like yours, but overall cost and effort is way lower. I wrote you a PM with some further details and questions, and doing this post to be able to show you a picture!
Many thanks and best regards,
Erik
PS. Ignore the foot, I am going to make something better.
I completed my speakers, I dare to say the look like yours, but overall cost and effort is way lower. I wrote you a PM with some further details and questions, and doing this post to be able to show you a picture!
Many thanks and best regards,
Erik
PS. Ignore the foot, I am going to make something better.
Attachments
Last edited:
Hi karap (and Gerrit). Thank you again. I can tell you some things already, but as this is not my thread and I am still optimizing these speakers, I will limit to this post only and any further information - after optimization - I will put in an own thread!
Woofers are the SB34NRX75-16 by SB acoustics.
SB Acoustics :: 12” SB34NRX75-16
Mid is the B&G NEO 10, available again at parts express.
Bohlender Graebener Neo10 Planar Transducer
Tweeter is the Mundorf AMT 17D2.2
Mundorf AMT 17D2.2 Air Motion Transformer kaufen bei hifisound.de
For the wiring I wanted something flat, and ended up buying some industrial cable from Conrad. 12 conductors is overkill, but this was the only cable they sell per meter. Now I use some conductors in parallel for less RDC.
LAPP OLFLEX(R) LIFT F Steuerleitung 12 G 1.50 mm2 Schwarz 0042006 Meterware
Filtering is done with 2x MiniDSP 2x4 and the amplification is done with an Arcam AVR250 (75W per channel, 6 channels used). I want to use some DIY valve amps eventually, but if doing one stereo amp is already quite some work, imagine 3 matching stereo amps...
Filters are IIR, but as I am working on them it doesn't make sense to post them now. A better xover is also in the plans...
Mechanically: I used black anodized extruded 20x20 profile to mount the holding structure. The NEOs are attached to that with 10x4mm steel profile, the AMT is attached to the NEO with thin (painted) alu profiles.
The woofers are attached to a 8mm thick MDF plate. I use 6x 100mm long M6 bolts, whose ends are suspended by 6 thick o-rings. I think the attached picture is better in describing this construction.
I have some weird noise from 25 to about 50Hz, I (wishfully) think the shelving filters from the DSPs are distorting there (I noticed some distortion with the shelving filters on the NEOs) - I will check when I have time. I like the heavy panels by Gerrit very much, but lacking the tools and skills to make something similar, I hope this suspended construction is sufficient to 1) avoid rattling noises from the woofer, 2) mechanically decouple them from the Mid and tweeter.
I am going to exchange the foot. I am thinking about getting something like this plate (40x40x4cm, 15.2kg) , but need to check if I can make holes in them.
Strukturplatte anthrazit 40x40x4cm kaufen bei Coop Bau+Hobby
I have 3 little kids, so progress is very very slow on these. And as they already sound very nice, way better than the speakers I used before, I find myself wasting my time on listening to them instead of further improving them with all these ideas
Woofers are the SB34NRX75-16 by SB acoustics.
SB Acoustics :: 12” SB34NRX75-16
Mid is the B&G NEO 10, available again at parts express.
Bohlender Graebener Neo10 Planar Transducer
Tweeter is the Mundorf AMT 17D2.2
Mundorf AMT 17D2.2 Air Motion Transformer kaufen bei hifisound.de
For the wiring I wanted something flat, and ended up buying some industrial cable from Conrad. 12 conductors is overkill, but this was the only cable they sell per meter. Now I use some conductors in parallel for less RDC.
LAPP OLFLEX(R) LIFT F Steuerleitung 12 G 1.50 mm2 Schwarz 0042006 Meterware
Filtering is done with 2x MiniDSP 2x4 and the amplification is done with an Arcam AVR250 (75W per channel, 6 channels used). I want to use some DIY valve amps eventually, but if doing one stereo amp is already quite some work, imagine 3 matching stereo amps...
Filters are IIR, but as I am working on them it doesn't make sense to post them now. A better xover is also in the plans...
Mechanically: I used black anodized extruded 20x20 profile to mount the holding structure. The NEOs are attached to that with 10x4mm steel profile, the AMT is attached to the NEO with thin (painted) alu profiles.
The woofers are attached to a 8mm thick MDF plate. I use 6x 100mm long M6 bolts, whose ends are suspended by 6 thick o-rings. I think the attached picture is better in describing this construction.
I have some weird noise from 25 to about 50Hz, I (wishfully) think the shelving filters from the DSPs are distorting there (I noticed some distortion with the shelving filters on the NEOs) - I will check when I have time. I like the heavy panels by Gerrit very much, but lacking the tools and skills to make something similar, I hope this suspended construction is sufficient to 1) avoid rattling noises from the woofer, 2) mechanically decouple them from the Mid and tweeter.
I am going to exchange the foot. I am thinking about getting something like this plate (40x40x4cm, 15.2kg) , but need to check if I can make holes in them.
Strukturplatte anthrazit 40x40x4cm kaufen bei Coop Bau+Hobby
I have 3 little kids, so progress is very very slow on these. And as they already sound very nice, way better than the speakers I used before, I find myself wasting my time on listening to them instead of further improving them with all these ideas
Attachments
Nope, I can't see anything, but the description shows that you trust that these techniques might work; I don't think so, as I've read in the past years these obscure things about coupling/ decoupling etc. but none really stands on its feets.
The woofers need to be coupled rigidally to the baffle; the baffle itself, with that thin part at the sides, being 8 mm MDF, will not do the duty of holding them firmly ( it flaps). About the other drivers ( midrange & tw ), they need to be totally decoupled from the vibrations transmitted by the woofers ( also, I wouldn't have placed the electronics right next to them, as Gerrit did ).
That can be easily done by the mean of rubber bands...
Ok, another post
Yesterday I removed the shelving low pass on the woofers and the strange noise between 25 and 50Hz is gone - it must have been some distortion on the miniDSP. It did not sound as clipping, so I will have to check what caused it. I am happy that it is not the mechanical part or the speakers that made these noises!
in the MiniDSP crossover I use LR filters.
Woofers: LP 4th order at 400Hz
Mid: bandpass, 2nd order HP at 400Hz and LP 4th order at 3kHz
Tweeter: 2nd order HP at 3kHz.
Furthermore I have protection caps for mid and tweeter, so that is another 6dB at 400Hz and 3kHz. There is the dipole roll off, so the 12dB LR + 6dB from caps + 6dB roll off should make for a 24dB acoustic HP roll off - but I have to work on improving this!
I have that problem with the SLP filter on the woofer now, but I am surprised that I need very little bass boost to compensate the dipole roll off. Probably because these woofers have a 0.7qts, our concrete building, and Dipole on axis
Crossover plans: I am still thinking about an analog xover. The MiniDSPs do hiss, and I have a chassis with 2x12 JFET buffers (ala B1 from NP) that would be enough for all the filtering - but Linktwitz transform would not be possible. Other filter I would like to experiment is S. Harsch XO as it allows 24dB LP and 12dB HP around Fc, exactly what I am using now, but with "better time alignment" (but I still need the protection caps).
So, this was enough threadjacking. When I have news I will post it in a new thread!
Finally, a picture of the room. my kids do leave the speakers in peace, luckily! I only fear when friends come over to play... the living room is about 5m x 7m (2.5m high).
Yesterday I removed the shelving low pass on the woofers and the strange noise between 25 and 50Hz is gone - it must have been some distortion on the miniDSP. It did not sound as clipping, so I will have to check what caused it. I am happy that it is not the mechanical part or the speakers that made these noises!
in the MiniDSP crossover I use LR filters.
Woofers: LP 4th order at 400Hz
Mid: bandpass, 2nd order HP at 400Hz and LP 4th order at 3kHz
Tweeter: 2nd order HP at 3kHz.
Furthermore I have protection caps for mid and tweeter, so that is another 6dB at 400Hz and 3kHz. There is the dipole roll off, so the 12dB LR + 6dB from caps + 6dB roll off should make for a 24dB acoustic HP roll off - but I have to work on improving this!
I have that problem with the SLP filter on the woofer now, but I am surprised that I need very little bass boost to compensate the dipole roll off. Probably because these woofers have a 0.7qts, our concrete building, and Dipole on axis
Crossover plans: I am still thinking about an analog xover. The MiniDSPs do hiss, and I have a chassis with 2x12 JFET buffers (ala B1 from NP) that would be enough for all the filtering - but Linktwitz transform would not be possible. Other filter I would like to experiment is S. Harsch XO as it allows 24dB LP and 12dB HP around Fc, exactly what I am using now, but with "better time alignment" (but I still need the protection caps).
So, this was enough threadjacking. When I have news I will post it in a new thread!
Finally, a picture of the room. my kids do leave the speakers in peace, luckily! I only fear when friends come over to play... the living room is about 5m x 7m (2.5m high).
Attachments
I use 4x10HD and no hiss or hum. Sometimes it starts to make crackling noise after switching presets. It goes away with power off-on. Erik, check the internal dip switches that control input and output sensitivity/voltage!
Passive xo might be rather difficult, specially the low end dipole loss eq thing..., despite the help from the room.
Passive xo might be rather difficult, specially the low end dipole loss eq thing..., despite the help from the room.
Audibly at around 10-20cm from the speakers. I use 2x the miniDSP 2x4 kit, and must admit I do not have any enclosure and I am powering them with a switched supply over the barrel. I read somewhere that a better PS reduces hiss, which was dismissed by others...
the dip switches are at 2 VRMS already, and my source is not putting that out.
Passive XO? One idea is to test active analog xover with filter sections between the sk170 JFET buffers. One should consider the levels indeed, but it is not difficult!?
the dip switches are at 2 VRMS already, and my source is not putting that out.
Passive XO? One idea is to test active analog xover with filter sections between the sk170 JFET buffers. One should consider the levels indeed, but it is not difficult!?
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.