Ricci's Skram Subwoofer & Files

[Ricci]

Is this an outdoor measurement? How far away is the nearest large object? Building, truck, etc?

Looks like about 8db down at 30Hz compared to 100Hz. The tuning seems to be a bit under 30Hz as well.  I'd expect about 4 or maybe 5dB down at tuning with those drivers. The HPF probably shaves another 1db off. Realistically this isn't too far off. Once all of the factors such as driver tolerances, construction methods, signal chain, measurement setup and atmospheric conditions are stacked up it can account for quite a bit of variation. I'd not worry about it too much if it's a little different from the model or other peoples measurements. 

Is the mic equidistant between the vents and the upper section or closer to one vs the other? That could account for another 1dB.

[peniku8]

2 hours ago, Ricci said:

Is this an outdoor measurement? How far away is the nearest large object? Building, truck, etc?

Looks like about 8db down at 30Hz compared to 100Hz. The tuning seems to be a bit under 30Hz as well.  I'd expect about 4 or maybe 5dB down at tuning with those drivers. The HPF probably shaves another 1db off. Realistically this isn't too far off. Once all of the factors such as driver tolerances, construction methods, signal chain, measurement setup and atmospheric conditions are stacked up it can account for quite a bit of variation. I'd not worry about it too much if it's a little different from the model or other peoples measurements. 

Is the mic equidistant between the vents and the upper section or closer to one vs the other? That could account for another 1dB.

Did you add baffle gain calculated in Edge to the hornresp prediction?
In my last project I got the predicted response to be within 1dB of the actual half-space response, but I had to double the baffle size in Edge (maybe that's the effect of the half-space loading: it mirrors the baffle on the ground basically), hence way more upper bass than hornresp predicted.
I'm not sure how this translates to larger cabs, but it was spot on with my single 21", a tad smaller than the Skram.
Hornresp was also fed with the set of complex inductance parameters. I used the specs for the 21ds115 you measured.
Same thing applied to my 1x12" sub. Model response was spot on with the measurement.

[Ricci]

Yes I was factoring that in as well.

[Alexlel]

On 7/13/2022 at 8:27 PM, Ricci said:

Is this an outdoor measurement? How far away is the nearest large object? Building, truck, etc?

Yes, this is outdoor ! There was a wall 10 meters on the left and a house 20 meters behind.

On 7/13/2022 at 8:27 PM, Ricci said:

Is the mic equidistant between the vents and the upper section or closer to one vs the other? That could account for another 1dB.

The mic was at 3 or 4 meters, on the ground, centered on the subs so probably closer to the upper section than the vents. 

[jngggggggg]

Has any fine folks on this thread had the chance to run impedence measurements on the skram? I thought about using the skhorn measurements as a close approximation if none were available but it would really help me for sizing up the right amplifier.

I am looking to run two Eminence NSW6021 (nominal 6 ohm) per amplifier and an considering two options:

1. operating a 2 channel amplifier in bridge mode with 2 drivers hung in parallel (net 3ohm). However, this would theoretically put a 1.5ohm load per channel (which is below the rated 2ohm minimum per channel) - that is unless the cabinet loading (acoustic impedance) raises the effective impedance to something more tolerable for the amplifier. 

2. Purchasing a 4 channel amplifier and also running it in (dual) bridge mode. Here I would hang one driver off each 'stereo bridged channel' and therefore only impose a 6 ohm load per bridged channel (ie: 3ohm spread across 4 channels which is more tolerable for the amplifier). +whatever cabinet effects may impart on the impedance the 'amplifier sees' 

First option is a bit more budget friendly so that would be my first pick. 

Amplifier is Wasi W15K or W15K4 respectively 

[ChikoRomantiko]

Hello again!
I don't know what the weather is like in your place, but it's still hot here in Croatia.

A week ago we took the sound system out to the festival, but unfortunately we didn't have 4 SKRAM as planned.

Otherwise, what I would try is that the lower SKRAM work from 25HZ to 60HZ and the upper two from 60HZ to 110HZ..
Why is that, since in one box we have 21B&C SW152 which would be for the lower range and 21RCF N551 which would be for the upper range(personally). Normally, we'll try how it would be if both boxes worked at the same frequency range and one more thing we didn't try is to close two more output ports from the lower SKRAM to get the depth, even though they still go quite low and sounds nice.

Currently, as you can see in the picture, instead of SKRAM, we put mini scoops that did a great job.
I can't wait to do it  , listen and measure the boxes to see what happens with the phase between the different drivers and how its sound overall with 2 more but I think it will be much better because as Ricci said, it is better to have more same boxes like this that work the whole range from 30 to 110HZ than for example like in the picture with mini scoops. 
I need to hear that combination to be able to make a comparison but I think it will better w SKRAM since there are no different boxes although this was very mellow tight and clean  

Other two almost finished !

SKRAM 21' RCF N551 (25-55) "MC2 E45 Bridged"

MINI SCOOPS 18' 18SOUND LW2400 (55-105) MC2 E45 Bridged

BPH 18' 18SOUND LW1200 (105-220) "MC2 E25 Bridged"

F1-DS210 (220-18K) "MC2 E15"

[Alexlel]

On 8/31/2022 at 2:39 AM, ChikoRomantiko said:

SKRAM 21' RCF N551 (25-55) "MC2 E45 Bridged"

MINI SCOOPS 18' 18SOUND LW2400 (55-105) MC2 E45 Bridged

BPH 18' 18SOUND LW1200 (105-220) "MC2 E25 Bridged"

F1-DS210 (220-18K) "MC2 E15"

Hello,

If you ever use this setup again, you shouldn't use the mini scoops and just cross your Skrams way higher.
If those BPHs are ES18, you can (and should) probably cross them at 80hz directly with the Skrams.
Using 3 boxes for the 25hz-220hz seems counterproductive to me, especially if you didn't put them properly in phase.

If you build 2 more Skrams, even if the boxes don't have the same drivers inside, let them play together, the phase should be pretty similar, you will win more than using them crossed separately

 

[ChikoRomantiko]

On 9/1/2022 at 12:48 PM, Alexlel said:

Hello Alexlel,

If you ever use this setup again, you shouldn't use the mini scoops and just cross your Skrams way higher.
If those BPHs are ES18, you can (and should) probably cross them at 80hz directly with the Skrams.
Using 3 boxes for the 25hz-220hz seems counterproductive to me, especially if you didn't put them properly in phase.

If you build 2 more Skrams, even if the boxes don't have the same drivers inside, let them play together, the phase should be pretty similar, you will win more than using them crossed separately

 

I agree with everything you said and I believe that 4 Skrams will do the job!
Otherwise, we only put bph above the skrams and they do all of the above!
I like sound system and I like to play with it so that in the end you understand keep it simple and smaart but the way to get there is fun  
There were no problems with the phases, in fact the best so far. Skram brings an earthquake and mini pushes it

similar words came from Ricci when I posted the first picture, in short, this is how I got strength that I wouldn't have otherwise and it was needed! , unfortunately we didn't have time to make two additional skrams (they are finished now) so this was a really good replacement.

[ChikoRomantiko]

On 9/1/2022 at 12:48 PM, Alexlel said:

Using 3 boxes for the 25hz-220hz seems counterproductive to me, especially if you didn't put them properly in phase.

Funktion One Dance Stack

[Alexlel]

On 9/6/2022 at 12:07 AM, ChikoRomantiko said:

Funktion One Dance Stack

Only in the DS3 configuration but they do it for a reason

Announced frequency response -3db (we can suppose these are once EQed) :

- InfraBass 218 : 25Hz - 80Hz
- DS15 : 90Hz - 270Hz
- F215 : 50Hz - 280Hz

They couldn't cross the InfraBass218 directly with the DS15 so they added some F215 in between.
But that doesn't mean it was the best solution, they are just offering what they can with their range of products.
 

In your case (and without any marketing EQ) :

- Skram : 26hz - 150hz
- 18" BPH (estimation) : 55hz - 220hz 

You don't need the mini scoops as you can cross the 18 BPH directly with the Skram.

You can add them if you want for sure, it's your system, if you want to take more bins, more amps and have a harder time to put everything in phase, you can, it's part of the fun 😁
I'm just unsure about the "real" gain you'll acquire from this.

Edited September 8, 2022 by Alexlel
Sounded agressive, didn't mean to !

[Ricci]

On 7/24/2022 at 10:35 AM, jngggggggg said:

Has any fine folks on this thread had the chance to run impedence measurements on the skram? I thought about using the skhorn measurements as a close approximation if none were available but it would really help me for sizing up the right amplifier.

I am looking to run two Eminence NSW6021 (nominal 6 ohm) per amplifier and an considering two options:

1. operating a 2 channel amplifier in bridge mode with 2 drivers hung in parallel (net 3ohm). However, this would theoretically put a 1.5ohm load per channel (which is below the rated 2ohm minimum per channel) - that is unless the cabinet loading (acoustic impedance) raises the effective impedance to something more tolerable for the amplifier. 

2. Purchasing a 4 channel amplifier and also running it in (dual) bridge mode. Here I would hang one driver off each 'stereo bridged channel' and therefore only impose a 6 ohm load per bridged channel (ie: 3ohm spread across 4 channels which is more tolerable for the amplifier). +whatever cabinet effects may impart on the impedance the 'amplifier sees' 

First option is a bit more budget friendly so that would be my first pick. 

Amplifier is Wasi W15K or W15K4 respectively 

A pair of the NSW in parallel should be closer to a 2 to 2.5 ohm min at the vent tuning once cable resistance and cabinet effects are factored in. Most of the freq range will be much higher in impedance but this would be pretty low for most amps bridged. I'd suggest the 4 channel amp method, or running the drivers in series which should present a 8 to 10 ohm min load to the bridged amp. Most touring amps are happiest at about 4ohms per channel. 

[DJimbo]

Hi! Thank you all for a riveting 40 pages of juicy tips. Thank you Ricci for the fantastic design!! I am sold. I am pulling the trigger on building 6 of these and I have a few questions for yall. In advance, please forgive my ignorance regarding everything. 

1. I see in a lot of other designs the "rounding off" of corners and deep pockets in the cabs. In the fluid mechanics world, you get a lot of turbulence around sharp corners and pockets in pipes and vessels. The SKRAM obviously sounds great to a lot of experts but it seems to have pretty aggressive corners and sharp directional changes. Im sure Ricci thought about this but I would love to know the thinking from a design perspective specifically with air as it moves around panel F and 90* turns in the back of the cab. Does it not really matter with subs?

2. Any guidance from anyone who has built these how tf you go about gluing these together? Are there certain groups of parts you do in different groups? I saw the one poster a while back who kinda sent it all at once.. Id love to better understand how to approach the gluing process.

3. Im looking at using the B&C 21SW152's in 4 ohm. Which amps would yall recommend? I am powering my Danley's with Linea. Ideally Id like to power all the subs off one amp for simplicity's sake (Linea 44M20, 20,000wattsRMS) using three channels split to two subs each wired in parallel. The amp goes down to 2 ohm but output is 3,000wattsrms for the 4 ohm and 1,500wattsrms for the 8 ohm respectively. If I bridge them I can apparently get 10,000 watts RMS at 4 ohms from each pair.. I dont know enough about amps to know whether it would be better to run two skrams off on one output in series or parallel given the wattage rating changes. Any thoughts about this? I could always change the drivers to 8 ohm and run them in parallel but the 1500 watt rms rating seems undersized..?

4. I will try to take a lot of photos and post the build here. I promise some nice videos once were rumbling.

5. I plan to take Ricci's files and have them cut out of 4x8' sheets (13x18mm, 1x12mm) with a cnc my cousin has. It seems like the only cuts that might not be able to be made with the CNC are the angled cuts for panel F and the front panel which I can manage on a table saw. It seems fairly straightforward but am I being short-sighted? 

6. Im budgeting about 11,500 for the six with all costs. I anticipate it being 2,000 less, however, these types of projects have a way of creeping up on budgets ;). Still way cheaper than used TH118's I have been scoping for a long time.

Thanks in advance! I am so stoked!!! 

[Domme]

4 hours ago, DJimbo said:

Hi! Thank you all for a riveting 40 pages of juicy tips. Thank you Ricci for the fantastic design!! I am sold. I am pulling the trigger on building 6 of these and I have a few questions for yall. In advance, please forgive my ignorance regarding everything. 

1. I see in a lot of other designs the "rounding off" of corners and deep pockets in the cabs. In the fluid mechanics world, you get a lot of turbulence around sharp corners and pockets in pipes and vessels. The SKRAM obviously sounds great to a lot of experts but it seems to have pretty aggressive corners and sharp directional changes. Im sure Ricci thought about this but I would love to know the thinking from a design perspective specifically with air as it moves around panel F and 90* turns in the back of the cab. Does it not really matter with subs?

2. Any guidance from anyone who has built these how tf you go about gluing these together? Are there certain groups of parts you do in different groups? I saw the one poster a while back who kinda sent it all at once.. Id love to better understand how to approach the gluing process.

3. Im looking at using the B&C 21SW152's in 4 ohm. Which amps would yall recommend? I am powering my Danley's with Linea. Ideally Id like to power all the subs off one amp for simplicity's sake (Linea 44M20, 20,000wattsRMS) using three channels split to two subs each wired in parallel. The amp goes down to 2 ohm but output is 3,000wattsrms for the 4 ohm and 1,500wattsrms for the 8 ohm respectively. If I bridge them I can apparently get 10,000 watts RMS at 4 ohms from each pair.. I dont know enough about amps to know whether it would be better to run two skrams off on one output in series or parallel given the wattage rating changes. Any thoughts about this? I could always change the drivers to 8 ohm and run them in parallel but the 1500 watt rms rating seems undersized..?

4. I will try to take a lot of photos and post the build here. I promise some nice videos once were rumbling.

5. I plan to take Ricci's files and have them cut out of 4x8' sheets (13x18mm, 1x12mm) with a cnc my cousin has. It seems like the only cuts that might not be able to be made with the CNC are the angled cuts for panel F and the front panel which I can manage on a table saw. It seems fairly straightforward but am I being short-sighted? 

6. Im budgeting about 11,500 for the six with all costs. I anticipate it being 2,000 less, however, these types of projects have a way of creeping up on budgets ;). Still way cheaper than used TH118's I have been scoping for a long time.

Thanks in advance! I am so stoked!!! 

If you have a CNC at hand you can route some grooves which should help with assembling and gluing process. I did not have one so I used lamello joints for easier assembling and increased stability.

This was my gluing order:
1. Baffle and horn
2. Base with ports
3. Braces
4. Outer sides

It was a pain in the ass though. I am glad my friend -a master carpenter who owns the workshop- helped with the gluing and I never knew that you can get sore muscles in each and every finger. You are going to need a lot of large and strong vices, too! Gonna post some pictures later on how it went.

From the fluid mechanics perspective i would say that you are moving large amounts of air back and forth repeatedly in different frequencies all at once. There will be turbulence all over the place no matter what you try. Even though I was also tempted to round of "F" I ultimately went with the original design (well almost...)

Good luck!

[Ricci]

Hello DJimbo and welcome. 

As far as assembling the cabs go. Clamps and more clamps are your friend. Other options that help are a brad nailer, or a pocket screw kit. 

If using the 21SW152 drivers best results will probably be with 2 to 4kw of amplifier rating per driver. Any more might get sketchy over long periods of time. Less would leave some of the dynamic capability on the table. I prefer to run fully bridged amp channels on bass when possible. 

Smoothing out the corners might help with airflow in an ideal scenario but it has drawbacks. It reduces the internal volume utilized by the driver. With bass size (air volume) is king. The Skram is a vented cab on the back side so it's a traditional ported arrangement there. Large flares and circular vents would be beneficial ideally but would greatly increase the size of the cab and its complexity. The front is a short horn/expanding slot. The same applies here. Ideally it would be a totally smooth, straight path, but packaging it into the cab dimensions requires compromises. At best these would be small gains in output / noise reduction, even if it was built ideally with a totally different (much uglier and unwieldy) form factor. I hope this explains why most bass cabs do not bother with dramatic smoothing of the air path. It comes with other tradeoffs. 

[Tahoejmfc]

13 hours ago, DJimbo said:

3. Im looking at using the B&C 21SW152's in 4 ohm. Which amps would yall recommend? I am powering my Danley's with Linea. Ideally Id like to power all the subs off one amp for simplicity's sake (Linea 44M20, 20,000wattsRMS) using three channels split to two subs each wired in parallel. The amp goes down to 2 ohm but output is 3,000wattsrms for the 4 ohm and 1,500wattsrms for the 8 ohm respectively. If I bridge them I can apparently get 10,000 watts RMS at 4 ohms from each pair.. I dont know enough about amps to know whether it would be better to run two skrams off on one output in series or parallel given the wattage rating changes. Any thoughts about this? I could always change the drivers to 8 ohm and run them in parallel but the 1500 watt rms rating seems undersized..?

Welcome to the Rabbit hole of BASS! Correct me if I am wrong with any of this.......

I use the B&C 21SW152's at 4ohm with a QSC PL380 amp. This amp drives 2 SKRAMS, with room to melt the coil if you turn the clip limit switch off.(I know from accidental experience) I have thought about running 4 x 8 ohm drivers with this one amp in series as well, but figure that would be pushing the amp alot and I typically use the amp at Burning Man and it was %*&#^@ hot this year so it prolly would not be the best idea as the amp would be turned all the way up instead of running at 50-60% like I currently am. I pair the 2 SKRAMS with Meyer Sound UPJ's and run the tops at -6db for most outdoor venues and -10db for most indoor venues (unless it gets really crowded, then I go to -4db outdoors for the tops and -6db for indoor.... Otherwise the tops are Too Bright). I have Meyer Sound UPQ's on order and will need to double my SKRAMS to keep up with the UPQ's output so I plan on building 2 more of these unless I just go straight to the Powersoft 30" M-Force subs but they are 12,000$ a pair with amp and you have to wait a year to get the drivers.

If you are going with 6 SKRAMS you will need quite the tops to compete as these Bass Bins output some serious BASS!!! Jay on here has quite the system with I think it was Danley tops, he might be one to DM. 

I would always cut in the grooves to build these boxes, serious forces going on here and you need the cabs to be rock solid, make sure you use the best Baltic Birch you can find, PU Glue and lots of pre-drilled screws. One option if you do not have access to a CNC router is to find a local makers space that has one, I used the TRUCKEE ROUNDHOUSE shop bot to make mine. 

GOOD LUCK AND MAY THE BASS BE WITH YOU!

[jay michael]

My pair of Danley sh46 are a pretty good match for 6 skrams, but they still outrun them a bit. I think 8 skrams would be the perfect balance. I've got another pair of skrams in the cutting phase, and another pair of sh46 on the way. Lots of skrams popping up in my area, there will be 12 in my city pretty soon, as well as 8 or 10 on the island. Been some planning discussing how to get them all in the same place sometimes soon

I'm planning an after summer report soon, was hectic busy with lots of great gigs

[DJimbo]

Wow thanks so much Domme, Ricci, Tahoejmfc, and Jay!! I really appreciate your expertise.

Noted on the gluing order. Sounds like I will have to build an arsenal of clamps and see what happens!

The comments about the amps makes sense. I will try to find some arrangement that pushes 4k to each driver with the minimal amount of boxes. 

The notes re: air dynamics all make sense and help me understand. Its such a compact box for a 21 that I'm sure maximizing volume was challenging to say the least. 

Tahoe JMFC which camp were you with? I was with Lux elixirs (fairly small audio setup this year).

Jay I'm surprised to hear that the 6 SKRAMS that have trouble keeping up with the Danleys. I would have assumed it would be the other way around. I have listened to the 46's at about 80% capacity and they are loud but not quite as loud as you might guess. Which drivers do you have in your SKRAMs?

Blessings!!

13 hours ago, Domme said:

If you have a CNC at hand you can route some grooves which should help with assembling and gluing process. I did not have one so I used lamello joints for easier assembling and increased stability.

This was my gluing order:
1. Baffle and horn
2. Base with ports
3. Braces
4. Outer sides

It was a pain in the ass though. I am glad my friend -a master carpenter who owns the workshop- helped with the gluing and I never knew that you can get sore muscles in each and every finger. You are going to need a lot of large and strong vices, too! Gonna post some pictures later on how it went.

From the fluid mechanics perspective i would say that you are moving large amounts of air back and forth repeatedly in different frequencies all at once. There will be turbulence all over the place no matter what you try. Even though I was also tempted to round of "F" I ultimately went with the original design (well almost...)
 

Good luck!

4 hours ago, Ricci said:

Hello DJimbo and welcome. 

As far as assembling the cabs go. Clamps and more clamps are your friend. Other options that help are a brad nailer, or a pocket screw kit. 

If using the 21SW152 drivers best results will probably be with 2 to 4kw of amplifier rating per driver. Any more might get sketchy over long periods of time. Less would leave some of the dynamic capability on the table. I prefer to run fully bridged amp channels on bass when possible. 

Smoothing out the corners might help with airflow in an ideal scenario but it has drawbacks. It reduces the internal volume utilized by the driver. With bass size (air volume) is king. The Skram is a vented cab on the back side so it's a traditional ported arrangement there. Large flares and circular vents would be beneficial ideally but would greatly increase the size of the cab and its complexity. The front is a short horn/expanding slot. The same applies here. Ideally it would be a totally smooth, straight path, but packaging it into the cab dimensions requires compromises. At best these would be small gains in output / noise reduction, even if it was built ideally with a totally different (much uglier and unwieldy) form factor. I hope this explains why most bass cabs do not bother with dramatic smoothing of the air path. It comes with other tradeoffs. 

3 hours ago, Tahoejmfc said:

Welcome to the Rabbit hole of BASS! Correct me if I am wrong with any of this.......

I use the B&C 21SW152's at 4ohm with a QSC PL380 amp. This amp drives 2 SKRAMS, with room to melt the coil if you turn the clip limit switch off.(I know from accidental experience) I have thought about running 4 x 8 ohm drivers with this one amp in series as well, but figure that would be pushing the amp alot and I typically use the amp at Burning Man and it was %*&#^@ hot this year so it prolly would not be the best idea as the amp would be turned all the way up instead of running at 50-60% like I currently am. I pair the 2 SKRAMS with Meyer Sound UPJ's and run the tops at -6db for most outdoor venues and -10db for most indoor venues (unless it gets really crowded, then I go to -4db outdoors for the tops and -6db for indoor.... Otherwise the tops are Too Bright). I have Meyer Sound UPQ's on order and will need to double my SKRAMS to keep up with the UPQ's output so I plan on building 2 more of these unless I just go straight to the Powersoft 30" M-Force subs but they are 12,000$ a pair with amp and you have to wait a year to get the drivers.

If you are going with 6 SKRAMS you will need quite the tops to compete as these Bass Bins output some serious BASS!!! Jay on here has quite the system with I think it was Danley tops, he might be one to DM. 

I would always cut in the grooves to build these boxes, serious forces going on here and you need the cabs to be rock solid, make sure you use the best Baltic Birch you can find, PU Glue and lots of pre-drilled screws. One option if you do not have access to a CNC router is to find a local makers space that has one, I used the TRUCKEE ROUNDHOUSE shop bot to make mine. 

GOOD LUCK AND MAY THE BASS BE WITH YOU!

40 minutes ago, jay michael said:

My pair of Danley sh46 are a pretty good match for 6 skrams, but they still outrun them a bit. I think 8 skrams would be the perfect balance. I've got another pair of skrams in the cutting phase, and another pair of sh46 on the way. Lots of skrams popping up in my area, there will be 12 in my city pretty soon, as well as 8 or 10 on the island. Been some planning discussing how to get them all in the same place sometimes soon

I'm planning an after summer report soon, was hectic busy with lots of great gigs

 

[jay michael]

I'm using the 21sw152. Sh46's can get stupid loud, especially when bi-amped. Two pair of them can cover 1500 to 2000 people for electronic dance music. While the Skram can really boogie,  its still a medium sized cabinet compared to other types of designs. Pretty typically for the Danley guys to recommend 6 th118's per pair of sh46, so I'd say my assessment is pretty accurate. This would be for heavy bass music mind you, for techno you could probably get away with fewer

[Tahoejmfc]

Has anyone used or considered using a IPAL driver in a Skram? Im guessing the box would have to change. 

[Father Francis]

On 9/18/2022 at 8:05 PM, Tahoejmfc said:

Has anyone used or considered using a IPAL driver in a Skram? Im guessing the box would have to change. 

And why would you think that ?, I think there’s only 9mm difference in the depth, and the box is half the Skp which is designed from Ipal, so I wouldn’t think there is any problems 

[Tahoejmfc]

30 minutes ago, Father Francis said:

And why would you think that ?, I think there’s only 9mm difference in the depth, and the box is half the Skp which is designed from Ipal, so I wouldn’t think there is any problems 

Because all of the Driver specs change, you cannot just look at the physical dimensions of the driver and say because it fits in the box it will sound ok. One major difference is the Vas changes from 7.0 ft3 for the 21sw152 to a smaller 5.47 ft3 for the ipal

21SW152 https://bcspeakers.com/en/products/lf-driver/21-0/4/21sw152-4

21ipal https://bcspeakers.com/en/products/lf-driver/21-0/1/21ipal

[Mike]

Hi All, Finally I have all the parts for my for my active versions built. I'm using NSW6021-6 21"  with Loto Dsp amp module from powersoft with either the 3004PFC2 or 4HV amplifier amp modules, I might try both amps options...The DSP has a few limit options available. What's the best value for the NSW6021-6 driver for the following limiters.  

1, TruePower TM

2, RMS Voltage

3, RMS current

4, Peak Limiter

 

Thanks

[chrapladm]

12 hours ago, Tahoejmfc said:

Because all of the Driver specs change, you cannot just look at the physical dimensions of the driver and say because it fits in the box it will sound ok. One major difference is the Vas changes from 7.0 ft3 for the 21sw152 to a smaller 5.47 ft3 for the ipal

21SW152 https://bcspeakers.com/en/products/lf-driver/21-0/4/21sw152-4

21ipal https://bcspeakers.com/en/products/lf-driver/21-0/1/21ipal

The Ipal works just fine in this cab. The simulations shows more peaky responce but works just fine. I think almost everything I have ever simulated for the 21SW152 will also work for the 21 IPAL. And so goes the 18SW115 and 18IPAL.

[Tahoejmfc]

would using an Ipal Driver over the standard driver like its brother the 21SW152 make a big difference? would I see a larger return for my money?

[chrapladm]

I believe the IPAL would be the choice to go if you were trying to maximize SPL density and had a capable amp to drive it with. IPAL has 22.5mm Xmax verse 16mm or whatever BC is going by.