some random pondering.
been contemplating building a set of BBcubes for which I already have the requisite Doc Mod drivers
however as they do thoughts cross my mind
I'd already planned to have each driver powered by a seperate amp. And then it occured to me that having drivers in teh same box ust add some compromise, i.e a 12" moving air at frequency x must exert an influence on the mid range which is trying to perfom at different frequencies. So WAF factor aside would they actually perform better in seperate cubes for each driver?
Seperate Cubes
-
- Posts: 278
- Joined: Sat Mar 03, 2018 2:35 pm
- Has thanked: 0
- Been thanked: 19 times
Seperate Cubes
Bedroom Rig
PiCorePlayer Squeezebox clone, Allo Boss Dac, NVA AP10H with Stepped Attenuator upgrade and external PSU, Audioquest Nightowl Cans, NVA mini BMU
Office Rig
PicorepLayer Squezeebox clone with HifiBerry DIGI+, NVA SSP Digital, Arcam AV9. NVA SSC, NVA AP10P, NVA LS5, NVA Cubettes, NVA Mini BMU
Kitchen Rig
PicorepLayer Squezeebox clone with HifiBerry DAC+, NVA SSC, NVA P50, Project AMPBox, Sonance Ceiling Speakers
PiCorePlayer Squeezebox clone, Allo Boss Dac, NVA AP10H with Stepped Attenuator upgrade and external PSU, Audioquest Nightowl Cans, NVA mini BMU
Office Rig
PicorepLayer Squezeebox clone with HifiBerry DIGI+, NVA SSP Digital, Arcam AV9. NVA SSC, NVA AP10P, NVA LS5, NVA Cubettes, NVA Mini BMU
Kitchen Rig
PicorepLayer Squezeebox clone with HifiBerry DAC+, NVA SSC, NVA P50, Project AMPBox, Sonance Ceiling Speakers
- karatestu
- Posts: 5975
- Joined: Sun Jan 08, 2017 4:40 pm
- Location: North Yorkshire
- Has thanked: 1879 times
- Been thanked: 1410 times
Re: Seperate Cubes
If you are doing a proper nva style speaker with no filters on the bass and mid then i don't see it being such a big problem. The 12" and 5" are getting exactly the same full range signal with the 12" not going as high because of its size and the doping.
However, i have my mid range in a seperate enclosure and i am planning on doing the same in my next version of it. It just seems like the ultimate thing to do imo. If putting the 5"in same enclosure as the 12" then due to the large volume the 5" will be very much over damped (i am guessing this as i dont know exactly what influence the 12" will have on the 5" if in same enclosure) I guess you may prefer that to the 5" being in a correctly sized box for qts of 0.7 or there abouts. Then again you may prefer seperate boxes.
Have you got a hunch about it ?
However, i have my mid range in a seperate enclosure and i am planning on doing the same in my next version of it. It just seems like the ultimate thing to do imo. If putting the 5"in same enclosure as the 12" then due to the large volume the 5" will be very much over damped (i am guessing this as i dont know exactly what influence the 12" will have on the 5" if in same enclosure) I guess you may prefer that to the 5" being in a correctly sized box for qts of 0.7 or there abouts. Then again you may prefer seperate boxes.
Have you got a hunch about it ?
DIY FREE ZONE
-
- Posts: 278
- Joined: Sat Mar 03, 2018 2:35 pm
- Has thanked: 0
- Been thanked: 19 times
Re: Seperate Cubes
Well from a sound point of view I can't help but feel removing any effects of driver interaction in the box cannot but be a good thing
As you said it should also allow no compromise on enclosure volume
Finally it should allow the mid-range to also fire upwards which follows the cube principle of the driver opposing the stand to minimize box movement.
All sounds right in theory to me at least
As you said it should also allow no compromise on enclosure volume
Finally it should allow the mid-range to also fire upwards which follows the cube principle of the driver opposing the stand to minimize box movement.
All sounds right in theory to me at least
Bedroom Rig
PiCorePlayer Squeezebox clone, Allo Boss Dac, NVA AP10H with Stepped Attenuator upgrade and external PSU, Audioquest Nightowl Cans, NVA mini BMU
Office Rig
PicorepLayer Squezeebox clone with HifiBerry DIGI+, NVA SSP Digital, Arcam AV9. NVA SSC, NVA AP10P, NVA LS5, NVA Cubettes, NVA Mini BMU
Kitchen Rig
PicorepLayer Squezeebox clone with HifiBerry DAC+, NVA SSC, NVA P50, Project AMPBox, Sonance Ceiling Speakers
PiCorePlayer Squeezebox clone, Allo Boss Dac, NVA AP10H with Stepped Attenuator upgrade and external PSU, Audioquest Nightowl Cans, NVA mini BMU
Office Rig
PicorepLayer Squezeebox clone with HifiBerry DIGI+, NVA SSP Digital, Arcam AV9. NVA SSC, NVA AP10P, NVA LS5, NVA Cubettes, NVA Mini BMU
Kitchen Rig
PicorepLayer Squezeebox clone with HifiBerry DAC+, NVA SSC, NVA P50, Project AMPBox, Sonance Ceiling Speakers
- terrybooth
- Posts: 4397
- Joined: Wed Jul 11, 2012 6:49 pm
- Location: West Yorkshire
- Has thanked: 499 times
- Been thanked: 250 times
Re: Seperate Cubes
I'm not a speaker designer, but I thought the point of the cubes is not so much how they interact internally but how they interact with the room. Sound isn't created iside the box but by a box within a box (the room) and the interaction of the two (providing we are dealing with room of domestic room height) is managed by moving the speakers in and out from walls (till the balance sounds right) and then toeing in to get the focus).
Pioneer PL71/DL103/ Phono2/HiFiPi/P90SA/TIS/CubixPro
- Latteman
- Posts: 1223
- Joined: Tue Aug 14, 2018 7:20 pm
- Location: S. Yorkshire
- Has thanked: 557 times
- Been thanked: 301 times
- Contact:
Re: Seperate Cubes
I use a 12”, 8” & tweeter in same cube
12” up, 8” & tweeter forward- off centre design
Using Nva 8” drivers & tweeters
Amps wired directly to the drivers
Agree with the above that it’s the interaction with the room that’s important, I’ve created a false ceiling above the cubes as original was high, glass & sloping
12” up, 8” & tweeter forward- off centre design
Using Nva 8” drivers & tweeters
Amps wired directly to the drivers
Agree with the above that it’s the interaction with the room that’s important, I’ve created a false ceiling above the cubes as original was high, glass & sloping
Analogue Source -
Denon DP47f; AT-VM95SH
GL-59; ARB uni pivot; AT- Signet
Ifi Zen Phono
Doug Self balanced Pre amp
Akai 4000DS mk2 R2R
Digital Sources- Argon Pi4 v2; IfI iUSB 3.0, Ifi Neo idsd Dac;
Tidal / Radio Paradise
Amplification Nva 300va mono blocks
Speakers Lii Audio F-15 in Open Baffle; Ls6
Weiduka AC8.8- for digital sources
Mini BMU for analog sources
Denon DP47f; AT-VM95SH
GL-59; ARB uni pivot; AT- Signet
Ifi Zen Phono
Doug Self balanced Pre amp
Akai 4000DS mk2 R2R
Digital Sources- Argon Pi4 v2; IfI iUSB 3.0, Ifi Neo idsd Dac;
Tidal / Radio Paradise
Amplification Nva 300va mono blocks
Speakers Lii Audio F-15 in Open Baffle; Ls6
Weiduka AC8.8- for digital sources
Mini BMU for analog sources
- Docfoster
- Posts: 231
- Joined: Tue Jun 18, 2019 11:06 am
- Has thanked: 33 times
- Been thanked: 129 times
- Contact:
Re: Seperate Cubes
The large movements of the woofer will cause pressure changes within a sealed cabinet (hence the “acoustic suspension” approach to speaker design).
Those pressure changes will act on the inside face of an exposed midrange cone. Tending to push it out and suck it in.
You probably want to avoid that, or at least check you can’t hear any unwanted effects.
You can avoid it by using an internal cabinet for the midrange (possibly just a sturdy cardboard tube as Goodmans used in their old Goodwoods design), or a midrange driver with a sealed back design (as Goodmans did in their even older Magisters. That midrange sounds utter shit these days, but modern alternatives are available!) Tho it sounds like you have already chosen your drivers.
Tweeters have sealed backs anyway, so need to worry about that.
Edit...Or yes...Build a whole separate cabinet for the midrange.
Those pressure changes will act on the inside face of an exposed midrange cone. Tending to push it out and suck it in.
You probably want to avoid that, or at least check you can’t hear any unwanted effects.
You can avoid it by using an internal cabinet for the midrange (possibly just a sturdy cardboard tube as Goodmans used in their old Goodwoods design), or a midrange driver with a sealed back design (as Goodmans did in their even older Magisters. That midrange sounds utter shit these days, but modern alternatives are available!) Tho it sounds like you have already chosen your drivers.
Tweeters have sealed backs anyway, so need to worry about that.
Edit...Or yes...Build a whole separate cabinet for the midrange.
System 1: JRiver MC24 > Dell Latitude 7270 > Asus Xonar Essence One Muses Edition DAC & pre- > One4 Class A power amp (with Dynamic PSU boards) > DIY Monacor SP-310CX speakers & DIY Dayton Audio SD315A-88 bass cab.
LC Audio Technology mains DC filter > Sovereign MTBPS balanced power supply
TQ (Wonfor) Ultra Black cables.
System 2: Anything with a headphone socket > Inca Tech Claymore > DIY Monacor SP-308CX speakers
LC Audio Technology mains DC filter > Sovereign MTBPS balanced power supply
TQ (Wonfor) Ultra Black cables.
System 2: Anything with a headphone socket > Inca Tech Claymore > DIY Monacor SP-308CX speakers
- karatestu
- Posts: 5975
- Joined: Sun Jan 08, 2017 4:40 pm
- Location: North Yorkshire
- Has thanked: 1879 times
- Been thanked: 1410 times
Re: Seperate Cubes
The Doc always said it was not a problem having bass & mid in the same enclosure. I assume this to be true but even though there may not be a problem perhaps seperate boxes are better. In my OCD head i have always preferrred the idea of seperation but i have no listening test to back that up. The following is only my opinion YMMV.
So you want the mid up firing ? Which direction are you going to point the 12 incher ? I have tried all sorts of combinations. For some reason i don't like side firing the bass or mid drivers. At the moment i am down firing the big bass cube (on 6" legs) with the smaller cab on top with mid up firing. Down firing didn't work for me originally when i only had one 12". Since revisiting it with two 12 inchers in isobaric config i do like it. Front firing the bass also works for me and i will have to choose at some point between that and down firing.
The Doc had to compromise a little with the bbcube imo. The box would have been an odd shape with bass and mid both up firing so he chose bass to fire up and mid sideways. As he always stressed getting the drivers movement in phase with the floor then getting the bigger of the drivers up firing was a priority. The mid is still a considerable mover and does deal with bass also (if no filters) so it must produce some unwanted movement 90 degrees out of phase with the floor ?
There has to be some compromise along the way i suppose. If religously following the in phase with the floor thing then you would either have to have both bass and mid up firing or do as i am trialing now and have bass down firing and mid up firing. It does work. But which works best, i am not completely sure yet. Cubes 1, 2 & 3 need to use a flat wall at the rear to enforce bass. It is usually recommended to have them real close to the back wall for that reason. Doc thought i would prefer bass driver at floor level firing forward for the Roy Allison effect. I originally agreed but down firing is extremely tempting.
I think with a 3 way design using big 12 incher it is less ctritical to get the mid / bass close to the back wall so you have more possibilities. I dont have a flat back wall to work with as mine are either in a bay window or with one window behind each speaker. Having the seperate big cube has helped no end with fine tuning and getting good bass. There is no lack of bass believe me but neither is it over blown or bumpy.
Good look with your project Monte and enjoy the design, build and of course the listening
So you want the mid up firing ? Which direction are you going to point the 12 incher ? I have tried all sorts of combinations. For some reason i don't like side firing the bass or mid drivers. At the moment i am down firing the big bass cube (on 6" legs) with the smaller cab on top with mid up firing. Down firing didn't work for me originally when i only had one 12". Since revisiting it with two 12 inchers in isobaric config i do like it. Front firing the bass also works for me and i will have to choose at some point between that and down firing.
The Doc had to compromise a little with the bbcube imo. The box would have been an odd shape with bass and mid both up firing so he chose bass to fire up and mid sideways. As he always stressed getting the drivers movement in phase with the floor then getting the bigger of the drivers up firing was a priority. The mid is still a considerable mover and does deal with bass also (if no filters) so it must produce some unwanted movement 90 degrees out of phase with the floor ?
There has to be some compromise along the way i suppose. If religously following the in phase with the floor thing then you would either have to have both bass and mid up firing or do as i am trialing now and have bass down firing and mid up firing. It does work. But which works best, i am not completely sure yet. Cubes 1, 2 & 3 need to use a flat wall at the rear to enforce bass. It is usually recommended to have them real close to the back wall for that reason. Doc thought i would prefer bass driver at floor level firing forward for the Roy Allison effect. I originally agreed but down firing is extremely tempting.
I think with a 3 way design using big 12 incher it is less ctritical to get the mid / bass close to the back wall so you have more possibilities. I dont have a flat back wall to work with as mine are either in a bay window or with one window behind each speaker. Having the seperate big cube has helped no end with fine tuning and getting good bass. There is no lack of bass believe me but neither is it over blown or bumpy.
Good look with your project Monte and enjoy the design, build and of course the listening
DIY FREE ZONE