Yeah, maybe a small fan together with dual ports to promote airflow to the outside? The usual vented speaker designs seem more focused on preventing distortion artifacts from compressed air under the dustcap being pumped under and around the coil. The more high-tech designs all seem to increase natural convection, but also decrease the amount of forced convection from bass tones.
Are you still searching for a low midrange?
There is the solution: https://www.bcspeakers.com/en/products/lf-driver/10/8/10NSM76
High Qms, membrane weight 5g more as the 8". Possible from 300-350Hz. Xmax in a useful range, not to much but enough. INSANE sensitivity, 4,5% and >100dBSpl in the needed range. 3" coil. 800W program power rating.
But the best - the cooling solution is built in! It's closed back with massive aluminium cooling, you can put it in a tube and let it open at the back of the speaker. Add a silent fan and you are done. Or do some clever tunels to get airflow (but these will make resonances, would not put them on the baffle).
I'm pretty sure you only need one of these monsters compared to 2 of the 8". The basket is made to keep a small distance to your midrange - but for sure it's way smaller in over all dimension as 2 8". And the look is less PA in my opinion.
You're welcome
There is the solution: https://www.bcspeakers.com/en/products/lf-driver/10/8/10NSM76
High Qms, membrane weight 5g more as the 8". Possible from 300-350Hz. Xmax in a useful range, not to much but enough. INSANE sensitivity, 4,5% and >100dBSpl in the needed range. 3" coil. 800W program power rating.
But the best - the cooling solution is built in! It's closed back with massive aluminium cooling, you can put it in a tube and let it open at the back of the speaker. Add a silent fan and you are done. Or do some clever tunels to get airflow (but these will make resonances, would not put them on the baffle).
I'm pretty sure you only need one of these monsters compared to 2 of the 8". The basket is made to keep a small distance to your midrange - but for sure it's way smaller in over all dimension as 2 8". And the look is less PA in my opinion.
You're welcome
When 8" - PHL 2513NdS also looks great:
https://www.google.com/url?sa=t&sou...0QFnoECBUQAQ&usg=AOvVaw2Q8Pq9uhzOQZeToBVimASs
The 63W - 1% THD would be 110dBSpl - that's more as some 8" can do at all. And THD stays low at 200Hz, you could cross over lower as 400Hz.
The PHL 8" I tested where better as typical PA 8" at low levels, compareable to high end HiFi drivers. And still can take the power of PA drivers and go loud.
There is a reason a lot of big studio monitors use them.
https://www.google.com/url?sa=t&sou...0QFnoECBUQAQ&usg=AOvVaw2Q8Pq9uhzOQZeToBVimASs
The 63W - 1% THD would be 110dBSpl - that's more as some 8" can do at all. And THD stays low at 200Hz, you could cross over lower as 400Hz.
The PHL 8" I tested where better as typical PA 8" at low levels, compareable to high end HiFi drivers. And still can take the power of PA drivers and go loud.
There is a reason a lot of big studio monitors use them.
How far off then would you feel the TF radiator and subsequent discussion with Art is? Seemed like a waste of time after designing it, so I didn't look at it again. I wonder why my concept wouldn't work nicely?
https://www.diyaudio.com/community/threads/volcano-subwoofer-cabs-design-and-build.415232/
Your concept was for a vented subwoofer. The 'cup' restricts air movement (which loses some cooling) and requires several precise holes which will after a while create rattling. Here it's a sealed enclosure, the cooling gain is a lot higher and much more needed, it will add a lot less weight to the speaker and is also much easier to build.
Maybe I am not following what you mean or the drawing is unclear? The cup is a collar that can be clamped onto the magnet increasing contact area between;
I dont follow this part?
Is it common for old school sheilded drivers to fail easier than thier unsheilded varients? I dont follow the logic of air circulation around the magnet or collar if the heat path is through the collar metal to the plate metal and not via air?
Could it be only to be contrary?
and
Which according to you is
I dont follow this part?
The collar can be made from a machined block, laminated plate, wrapped sheet or bent plate
Is it common for old school sheilded drivers to fail easier than thier unsheilded varients? I dont follow the logic of air circulation around the magnet or collar if the heat path is through the collar metal to the plate metal and not via air?
Could it be only to be contrary?
Shielded drivers were only made to be compliant to tube screens. The shield was never meant to increase the heat dispersion.
The voice coil is the thing which creates the heat. The heat is not transferred by contact but through the air in the magnet gap. If you don't exchange the air there, the VC will create a heat spot. If you impede the air circulation at that exact point, it doesn't matter what comes after. Compare it to a car. It doesn't matter if you have 2000 Hp if the skinny 150mm wide tires can't get it on the road. No added turbo and increased compression or blower will make your car accellerate any faster unless you fix the point that's the bottleneck.
Ha! That's a good one!
That is true, but does that exclude its effect on air circulation because its intent is interference shielding? If that thing doesn't kill the driver than why would a more open collar be bad for it
I referenced the subsequent discussion after publishing the concept where a mod with the pickup plate changed to two layers and with the vent blowing onto the second plate. The standoffs changed to radial fins to further collect the heat from the vent output. The drivers action does not create a continuous pump but rather an oscillating a bit of air vortex around that pickup area. This is a solid way to implement a heat sink to external air for any driver size and a practical way design a "4mm plate stuck to the magnet and going to the outside". At some point one must then measure, cut and attach. Generalising does not make a part
Are you still searching for a low midrange?
There is the solution: https://www.bcspeakers.com/en/products/lf-driver/10/8/10NSM76
High Qms, membrane weight 5g more as the 8". Possible from 300-350Hz. Xmax in a useful range, not to much but enough. INSANE sensitivity, 4,5% and >100dBSpl in the needed range. 3" coil. 800W program power rating.
But the best - the cooling solution is built in! It's closed back with massive aluminium cooling, you can put it in a tube and let it open at the back of the speaker. Add a silent fan and you are done. Or do some clever tunels to get airflow (but these will make resonances, would not put them on the baffle).
I'm pretty sure you only need one of these monsters compared to 2 of the 8". The basket is made to keep a small distance to your midrange - but for sure it's way smaller in over all dimension as 2 8". And the look is less PA in my opinion.
You're welcome
what aboutthe classic PHL 2460 ?
It's a shame SB doesn't do 4ohm coils for their Audience range. The neo motor 8" looks like good value, high efficiency, decent xmax... All the boxes ticked. At 4ohm it would be rated @96db too.....
There does appear to be a small discontinuity around 450hz, as for how audible that is I don't know...
There does appear to be a small discontinuity around 450hz, as for how audible that is I don't know...
I like the JBL 2118H better than the JBL 2119H. The 10 inch JBL 2123H is my favorite full size mid-range driver. (less $ too)
The shielding reduces the heat dissipation. How much depends on the construction of the shielding cup. When you compare the size of a shielded driver with its otherwise identical twin without shielding, the former is often noticeable bigger which means that the shielding cup encloses at least some air, which is equal to thermal insulation. I doubt there were drivers killed by that because the need of high power and being able to put it right next to a tube screen (which is in size somewhat limited -> audience size/number).
To have fins directly in the vent or air stream optimizes the cooling but creates other problems. The vortex got the positive effect of air exchange but the air speed of the port creates noise on those fins. It strongly depends on its construction and use, so it's difficult to generally say if it's good or bad. But the circumstances are what's really important. For a subwoofer it's not the goal to drive it permanently to its power limits, if you need it louder, it's a lot easier to just put more of them, that doesn't matter because you can't locate them by ear and you want them to live as long as possible. For the midrange that's a completely different animal because you have often just a limited size and an exact position you need them to be.
For a subwoofer it's a bad idea to maximize just the thermal side, the driver has to endure mechanical stress too and the manufacturer usually balances both already. Modern PA drivers are often already optimized to have air exchange so some vents (ie below the spider) could be increased in size which would reduce losses but they benefit more from the air exchange. If you put a collar around the magnet, these vents don't work like they have been engineered, same goes for the bores which ventilate the voice coil. An Example:
15BG100
That's a thermally highly optimized driver which will not profit but suffer from a collar. It can handle 2kW power. And if you give it a collar, and it would increase the cooling further, then it will probably die from a mechanical failure. To recone it (or replace it) you have to disassemble it from the collar and it takes several times longer to do that. Now the replacement driver got maybe a different tolerance or they changed the basket or magnet just half a mm and your collar doesn't fit the new driver anymore. Or maybe the driver isn't in production anymore but your collar only fits this specific driver, which makes your collar obsolete as well and you have to build a completely new enclosure instead of being able to switch to another driver.
Midrange drivers don't have such extremely hard mechanical work to do, they rarely do more than 2mm excursion (and that's why you don't look for high excursion in a mid driver), which means, the point of failure will likely be the VC (unless the cone gets smashed in etc). That's the reason it's a good idea for a mid driver but not that great for a subwoofer.
While a great sounding driver I would aim for something with more sensitivity, bigger coil/higher power handling and probably even less Xmax for this project.
With less demanding goals in SPL and lower cross over this is for sure one of the best 8" you can choose. (e.g. in a 2.5way home cinema satelite)
I agree, the PHL 2460 is more aimed for a mid-bass application for a small size top. In that situation it's performing nicely, For such a top, a 2" VC is very reasonable. However, you are also right about it being a mid driver. For a direct radiating 3/15 it works well, for a high spl mid situation however, it does not.
hi these look amazing this is the sort of speaker I'd love to build .have you documented this build at all? or would you mind sharing any general info about them thanks James
@jccart wrote: "hi these look amazing this is the sort of speaker I'd love to build .have you documented this build at all? or would you mind sharing any general info about them thanks James"
Thank you very much!
Sorry, I don't have any in-process photos.
The two midbass chambers are separated from the area behind the horn and have non-parallel internal walls. The sides of the horn chamber are open to the outside world (well, the world inside the wall) for a bit better cooling. The 21" ported subwoofer design is pretty straightforward, there is one 4" diameter Precision Port in each corner so that the airload on the back of the cone is symmetrical to prevent cone-rocking (which is more likely to be an issue on large-diameter woofers with long voice coils). You can also use triangular corner ports but I wanted to make the port lengths user-adjustable. The upper boxes are angled downwards a few degrees to aim directly at the mix position.
Passive crossover between midwoofers and horn, then active between upper box and subwoofer. The tradeoffs in the crossover between midwoofers and horn were juggled towards higher power handling a bit moreso than would be the case in a home audio version.
Are you thinking of something for home audio, or for a studio, or something else?
Thank you very much!
Sorry, I don't have any in-process photos.
The two midbass chambers are separated from the area behind the horn and have non-parallel internal walls. The sides of the horn chamber are open to the outside world (well, the world inside the wall) for a bit better cooling. The 21" ported subwoofer design is pretty straightforward, there is one 4" diameter Precision Port in each corner so that the airload on the back of the cone is symmetrical to prevent cone-rocking (which is more likely to be an issue on large-diameter woofers with long voice coils). You can also use triangular corner ports but I wanted to make the port lengths user-adjustable. The upper boxes are angled downwards a few degrees to aim directly at the mix position.
Passive crossover between midwoofers and horn, then active between upper box and subwoofer. The tradeoffs in the crossover between midwoofers and horn were juggled towards higher power handling a bit moreso than would be the case in a home audio version.
Are you thinking of something for home audio, or for a studio, or something else?
thankyou that's still a lot of good information . it would be for home audio, I'm going to be building a decent sized (maybe 8x4m )garden room as a workshop and I'd like to build something amazing like this . I might store some of my audio collection down there if I can figure out a way to keep everything clean and dust free. . How far do you think you'd need to be away from something with larger midrange drivers like this ? I was thinking with a mtm the front baffle could be angled like this > .
thanks for taking the time to talk about your build so far
thanks for taking the time to talk about your build so far