B&C 18SW115 vs PD.1845. IN

Jump to Latest
E

ErnieM

Member
Joined 2009
1. How many does he have?
2. What driver is it loaded with?
3. What's powering them and what processor settings are used?
3a. Have measurements been done?
4. Are the driver's tightly mounted with no air leaks?
5. Are they mobile or installed in one location?
6. What's currently lacking?

There is much to consider before spending cash on drivers... especially with horns. Switching drivers without considering the above could easily result in a side step or worse.
 
M

mars1234

Member
Joined 2013
Hi
Currently he has PD 1850 drivers- 12 cabinets.

The upgrade to the B&C 18SW115 or the Neo PD 1845 IN
Should be be double the power capability ...

Hes has an XTA APA 4E8 amp ... and XTA DP548 DSP.
So lots of limiting available.

Portable set up ... well a truck as they're large!!

I've measured them and they look good in the time domain. And sound good. A bit lacking
Down from 60 hz but theres a bit of LF Eq boost in the DSP.
Louder and less cabinets to haul is the goal ... 8 x subs across
The stage should be enough for most of the
Events he does.

Was looking for experience with the PD 1845 IN

Cheers
Martin
 
E

ErnieM

Member
Joined 2009
Big stack!

The potential long-term increase in output per box will be offset by power compression due to hot sealed back chambers.
Those high ratings depend on very high air exchange through the motor structure.
Without that feature, the thermal failure point will be similar to the 1850 or possibly worse due to the smaller voicecoils and motor structure.
It will get quite toasty in there without some kind of metal heat sink to the outside of the cabinet. Wood holds in heat quite well.

Tapped horns/scoops/vented boxes have an advantage in this regard.

It might be worth testing one horn with the old driver and another with the new model of your choosing.
Maybe there will be enough increase in peak output(due to larger xmax/xvar ratings) to justify new drivers. This is the only real way to know for sure.

I think I saw some Horn Response input parameters on that linked thread. Comparing sims will narrow down the best available alternative.
 
Last edited:
M

mars1234

Member
Joined 2013
Thanks

Yes the heat build up which has been discussed a lot is why I build tapped horns. The 18SW115's are awesome in Arts Keystone sub.

Theres lots of 50 - 40hz and they measure well. I've never felt them getting that hot.

I'm going to measure a keystone and SBH - both using the 18SW115 driver so it will be interesting ... I'll report back

Cheers
Martin
 
weltersys

weltersys

Member
Joined 2008
mars1234 said:
I'm going to measure a keystone and SBH - both using the 18SW115 driver so it will be interesting ... I'll report back
Click to expand...
Martin,

Mark Oldroyd, the technical director for Precision Devices (finally) got back to me today regarding the voice coil winding depth on the PD1845-1N, it is 37mm, not 16mm as posted in the preliminary specifications, so a 16mm Xvar does appear possible.

Did you happen to do the Keystone and SBH comparison yet?

Art
 
ICG

ICG

Disabled Account
Joined 2007
ErnieM said:
The potential long-term increase in output per box will be offset by power compression due to hot sealed back chambers.
Those high ratings depend on very high air exchange through the motor structure.
Without that feature, the thermal failure point will be similar to the 1850 or possibly worse due to the smaller voicecoils and motor structure.
It will get quite toasty in there without some kind of metal heat sink to the outside of the cabinet. Wood holds in heat quite well.
Click to expand...

Your objection is well founded. There are horn constructions which are constructed with the magnet structure in the throat, which reduces the heat a lot because there can be air exchange.

ND drivers are generally not the best choice for horn constructions because the big ferro magnet acts as a heat-peak-equalizer and as a heatsink. Besides that, the driver isn't the main weight of horn speakers and doesn't change the handling much since you need two ppl for stacking them (more or less comfortably) anyway.

ErnieM said:
Tapped horns/scoops/vented boxes have an advantage in this regard.
Click to expand...

Definitely. Esp tapped horns can usually take a lot more abuse and forgive power peaks a lot more. FLHs got often the problem of a mechanical driver breakdown because of the cone folding or tearing. FLHs should be used below the nominal driver power rating because of the heat of the VC being difficult to dissipate and the mechanical stress of the cone anyway.

ErnieM said:
It might be worth testing one horn with the old driver and another with the new model of your choosing.
Maybe there will be enough increase in peak output(due to larger xmax/xvar ratings) to justify new drivers. This is the only real way to know for sure.
Click to expand...

I agree. To swap the drivers do not give the increase in spl most ppl expect since 1-2 dB more are mostly not noticeable but the driver often can't take the increased load mechanically or power wise because of the thermal situation it has to work in. Most drivers can't take the power increase because the bad heat dissipation situation in the horn and the advanced venting construction does not work because the lack of fresh air exchange. The VC got only 2mm diameter difference, the spl is the same, there is none potential increase of spl. Not even a fraction of a dB!

If you need more spl, put up more subs. That not only increases the spl and extends the bottom frequency response but also the punch by a lot. Even more so outdoors (which swallows tons of bass).
 
M

mars1234

Member
Joined 2013
weltersys said:
Martin,

Did you happen to do the Keystone and SBH comparison yet?

Art
Click to expand...

Art,

not yet, Covid took hold in NZ for a bit but it's easing now - The SBH's subs are a few hundred Klms away, I'll be there in the next few weeks with my 18SW115s. - I've got a class 1 SPL meter and calibrator so I'll get some tone measurements 50 - 70 volts ...

cheers
Martin
 
Last edited:
M

mars1234

Member
Joined 2013
weltersys said:
Martin,

Mark Oldroyd, the technical director for Precision Devices (finally) got back to me today regarding the voice coil winding depth on the PD1845-1N, it is 37mm, not 16mm as posted in the preliminary specifications, so a 16mm Xvar does appear possible.

Did you happen to do the Keystone and SBH comparison yet?

Art
Click to expand...

thanks,

I've used and measured the PD1850's - ceramic drivers - and they sounded good in the SBH's. They were 22kgs so the cabs were quite heavy.

My bet is on the B&C 18SW115 as the winner ...

Cheers
Martin
 
M

mars1234

Member
Joined 2013
Smitske96 said:
Did you have the opportunity to do some measurements on the SBH? I saw some on speaker plans forum and they did not look al to good..
Click to expand...

Hi

I'm still looking for measurements but I'll say that the SBH subs sound very musical with plenty of output. They start to gently roll off at 70 ish. I had quite a bit of boost from 70. (Low shelving boost + 8 and had plenty of amplifier headroom to do so) The B&C 18sw115 drivers haven't arrived yet so no comparisons yet.

There were a few cuts above 100 but nothing crazy.

I'll attach the measurement I managed to find on speaker plans forum once I can find it.

My measurements looked nothing like those? - no dip at 50hz and very smooth throughout the passband. Xover - 40 HPF - 85 LPF

Drivers loaded were PD1850s as recommended. The 18sw115s will be an improvement below 70 - from experience !!

The 8 SBH subs were centred clustered. 6 on their sides at time zero plus one each side vertical. Half a millisecond of delay for the phase traces to look nice off axis. Best described as a delta - mono sub

Measurement system:
Systune Pro
Ground plane measurement.

CRowd was 2000 ish and no complaints - very even across a wide area.
 

Attachments

  • IMG-0349.JPG
    IMG-0349.JPG
    333.6 KB · Views: 73
You must log in or register to reply here.
Top Bottom