• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Active bass module plans (for Directiva and more)

Rick Sykora

Major Contributor
Forum Donor
Joined
Jan 14, 2020
Messages
3,719
Likes
7,507
Location
Stow, Ohio USA
Ok, almost have my table saw cleared and speaker test stand back in place. As I have mentioned elsewhere, I have a few drivers already and am contemplating how to deploy them for many options to suit different needs. First of all, do not expect to use any drivers much larger than 8-inch ones. I simply do not have the inclination to deal with building boxes that large. That said however, will use multiple drivers to move enough air to energize most medium to large rooms. All current plans are for these modules to employ active crossovers. As with Directiva, likely these will be minidsp 2x4 or better. Expect the filters to be simple enough to be used with other active crossovers too.

I mentioned in the main thread that I want to consider how bass module might be deployed as a traditional monopole and also as a cardioid. As testing the cardioid will be easier outdoors, the monopoles will come first as weather here will not allow much outdoor activity for a few months. :eek:

One major consideration for these bass modules is height. Unlike a subwoofer, they are intended to support having another speaker on top of them. For either an r1 or r2 speaker, those cabinets are around 14-16 inches high. One plan is to use the Denovo tower for a bass module cabinet, it is 34 inches tall. This would put a tweeter at around 44 inches high. At my seating height on my family room couch, this is about right. Slouching a bit, it is a bit lower, so plan to make the larger cabinet a little shorter. If it has a plinth, may need to be even shorter still. For right now, the cabinets are cut to around 32 inches high. In case you missed, the initial drivers used are:
  1. Dayton Esoteric woofer(s) in the Denovo tower cabinet.
  2. Dayton RS225 woofer(s) in a larger custom tower.
Both of these cabinets are large enough to support vented alignments and therefore plenty of room for sealed options. Expect other drivers will be considered (notably there are better candidates for a sealed enclosure), but I think these are solid choices for some initial prototypes. I wanted drivers that could be used in multiple and be reasonably affordable. I have a couple of amplifier projects wrapping up next week. So, plan to start the bass modules in mid-January. :cool:
 

alex-z

Addicted to Fun and Learning
Joined
Feb 19, 2021
Messages
921
Likes
1,714
Location
Canada
The new GRS 8SW-4HE is an interesting proposition at $50. It has relatively high inductance, but a lot of excursion and a low resonant frequency. Been enjoying the 12" version in some cheap builds lately.


At that price you could run 2 per cabinet.

Edit: Assuming the manufacturer specs are right (probably off by 5-10%), 2 of them in a 1.16ft sealed cabinet has QTC at .784, -3dB at 44Hz, -10dB at 26.5Hz.

Running with no high-pass, 190 watts is safe down to 10Hz. At 44Hz, that gives 105.4dB of SPL @ 1m half-space.

I did select "simulate voice coil inductance" when using WinISD.
 
Last edited:

Everett T

Addicted to Fun and Learning
Forum Donor
Joined
Aug 2, 2020
Messages
715
Likes
595
The new GRS 8SW-4HE is an interesting proposition at $50. It has relatively high inductance, but a lot of excursion and a low resonant frequency. Been enjoying the 12" version in some cheap builds lately.


At that price you could run 2 per cabinet.

Edit: Assuming the manufacturer specs are right (probably off by 5-10%), 2 of them in a 1.16ft sealed cabinet has QTC at .784, -3dB at 44Hz, -10dB at 26.5Hz.

Running with no high-pass, 190 watts is safe down to 10Hz. At 44Hz, that gives 105.4dB of SPL @ 1m half-space.

I did select "simulate voice coil inductance" when using WinISD.
That's a beefy magnet structure!
 
OP
Rick Sykora

Rick Sykora

Major Contributor
Forum Donor
Joined
Jan 14, 2020
Messages
3,719
Likes
7,507
Location
Stow, Ohio USA
The new GRS 8SW-4HE is an interesting proposition at $50. It has relatively high inductance, but a lot of excursion and a low resonant frequency. Been enjoying the 12" version in some cheap builds lately.


At that price you could run 2 per cabinet.

Edit: Assuming the manufacturer specs are right (probably off by 5-10%), 2 of them in a 1.16ft sealed cabinet has QTC at .784, -3dB at 44Hz, -10dB at 26.5Hz.

Running with no high-pass, 190 watts is safe down to 10Hz. At 44Hz, that gives 105.4dB of SPL @ 1m half-space.

I did select "simulate voice coil inductance" when using WinISD.

Thanks, but does not look like there is an 8 ohm version unfortunately.

Did remind me that the Peerless SLS would fit the bill for sealed though.:cool:
 

Colonel7

Addicted to Fun and Learning
Joined
Feb 22, 2020
Messages
623
Likes
930
Location
Maryland, USA
Thanks, but does not look like there is an 8 ohm version unfortunately.

Did remind me that the Peerless SLS would fit the bill for sealed though.:cool:
Peerless is getting out out of the DIY market:confused: . What’s currently in inventory is pretty much it
 
OP
Rick Sykora

Rick Sykora

Major Contributor
Forum Donor
Joined
Jan 14, 2020
Messages
3,719
Likes
7,507
Location
Stow, Ohio USA
Peerless is getting out out of the DIY market:confused: . What’s currently in inventory is pretty much it

Is this official Peerless statement or just that they seem to want higher volume business?

Seems if the volume is there, the resellers with deep pockets help buffer this. Noticed this about MOQs on their drivers at Parts Express, but Digikey (recently?) started carrying Peerless and the more popular SDS and SLS drivers are readily available. A quick check in Europe channels follows the same pattern.

If true, might seem they are less friendly to DIY than in the past, but may simply be a change in their channel management?
 

abdo123

Master Contributor
Forum Donor
Joined
Nov 15, 2020
Messages
7,452
Likes
7,988
Location
Brussels, Belgium
The new GRS 8SW-4HE is an interesting proposition at $50. It has relatively high inductance, but a lot of excursion and a low resonant frequency. Been enjoying the 12" version in some cheap builds lately.


At that price you could run 2 per cabinet.

Edit: Assuming the manufacturer specs are right (probably off by 5-10%), 2 of them in a 1.16ft sealed cabinet has QTC at .784, -3dB at 44Hz, -10dB at 26.5Hz.

Running with no high-pass, 190 watts is safe down to 10Hz. At 44Hz, that gives 105.4dB of SPL @ 1m half-space.

I did select "simulate voice coil inductance" when using WinISD.

I bought the woofer for a project. Build material is surprisingly decent for the price.

I haven’t built a box for them yet but everything is ordered already.
 

abdo123

Master Contributor
Forum Donor
Joined
Nov 15, 2020
Messages
7,452
Likes
7,988
Location
Brussels, Belgium
The new GRS 8SW-4HE is an interesting proposition at $50. It has relatively high inductance, but a lot of excursion and a low resonant frequency. Been enjoying the 12" version in some cheap builds lately.


At that price you could run 2 per cabinet.

Edit: Assuming the manufacturer specs are right (probably off by 5-10%), 2 of them in a 1.16ft sealed cabinet has QTC at .784, -3dB at 44Hz, -10dB at 26.5Hz.

Running with no high-pass, 190 watts is safe down to 10Hz. At 44Hz, that gives 105.4dB of SPL @ 1m half-space.

I did select "simulate voice coil inductance" when using WinISD.

Hey Alex, I've been having leak problems with the gasket tape that comes per-installed on the driver. Did you do something about it?
 

alex-z

Addicted to Fun and Learning
Joined
Feb 19, 2021
Messages
921
Likes
1,714
Location
Canada
Hey Alex, I've been having leak problems with the gasket tape that comes per-installed on the driver. Did you do something about it?

The 12" version didn't come with a gasket. I used 3/16" thickness weather stripping foam on my subwoofers.

RTV gasket maker also works well but is tougher to remove in the future.
 

mcdn

Addicted to Fun and Learning
Forum Donor
Joined
Mar 7, 2020
Messages
584
Likes
821
@Rick Sykora, a couple of thoughts about what might make a monopole build "interesting" vs the majority of commercial designs, primarily focused on reducing floor bounce issues:
  • A column of smaller drivers
  • 1 higher output driver close to the floor (but then integration with the mid bass is tricky).
  • Splitting into sub and bass sections: a sub driver close to the floor and a bass driver nearer the top
Those assume the drivers are all on the front face. You could also consider doing an opposed pair towards the top and another pair lower down, which would be of more benefit in solving construction issue before going dipole.
 

abdo123

Master Contributor
Forum Donor
Joined
Nov 15, 2020
Messages
7,452
Likes
7,988
Location
Brussels, Belgium
The 12" version didn't come with a gasket. I used 3/16" thickness weather stripping foam on my subwoofers.

RTV gasket maker also works well but is tougher to remove in the future.

This is strange, mine came with a gasket under the metal frame.

Edit: It did not, not sure why I experienced this brain fart.
 
Last edited:

voodooless

Grand Contributor
Forum Donor
Joined
Jun 16, 2020
Messages
10,610
Likes
18,748
Location
Netherlands
What’s the point of using two 5mm Xmax drivers if you can have one with 10mm? I bet the RSS210HO-8 would be a better choice than the Esoteric as a subwoofer. You can still fit two, but for half the price and double the output.
 

abdo123

Master Contributor
Forum Donor
Joined
Nov 15, 2020
Messages
7,452
Likes
7,988
Location
Brussels, Belgium
What’s the point of using two 5mm Xmax drivers if you can have one with 10mm? I bet the RSS210HO-8 would be a better choice than the Esoteric as a subwoofer. You can still fit two, but for half the price and double the output.

Sensitivity and Directivity control.
 

voodooless

Grand Contributor
Forum Donor
Joined
Jun 16, 2020
Messages
10,610
Likes
18,748
Location
Netherlands
Sensitivity and Directivity control.
You can still use two woofers, only at about half the cost. You even need less volume. That should take care of the directivity control.

Sensitivity? It's only a 2.5 dB difference. Power is cheap, and the RSS can take a lot. Two will take 600W. For an active sub, sensitivity should not be very high on the list, especially with small drivers and not so much enclosure volume.

What you get back is more important: almost 4 dB more maximum output.
 

abdo123

Master Contributor
Forum Donor
Joined
Nov 15, 2020
Messages
7,452
Likes
7,988
Location
Brussels, Belgium
Also break-up mode control is incredibly important, I haven’t looked at the two woofers in detail but the crossovers (in the bass at least) will likely be active in R2 so we can’t electromechanically dampen them with a notch filter.
 

voodooless

Grand Contributor
Forum Donor
Joined
Jun 16, 2020
Messages
10,610
Likes
18,748
Location
Netherlands
Also break-up mode control is incredibly important, I haven’t looked at the two woofers in detail but the crossovers (in the bass at least) will likely be active in R2 so we can’t electromechanically dampen them with a notch filter.
Why not? You can always add a notch to your liking. The breakup of the RSS is at 5 kHz. I doubt that will be a problem for a subwoofer.
 
OP
Rick Sykora

Rick Sykora

Major Contributor
Forum Donor
Joined
Jan 14, 2020
Messages
3,719
Likes
7,507
Location
Stow, Ohio USA
What’s the point of using two 5mm Xmax drivers if you can have one with 10mm? I bet the RSS210HO-8 would be a better choice than the Esoteric as a subwoofer. You can still fit two, but for half the price and double the output.
Agree, if the target was a built-in subwoofer, drivers like the RSS210 would be appropriate. The point of calling it a bass module is that it crosses higher than a typical subwoofer. Hence the woofers I have initially selected are geared that way. There are lots of good choices depending on your budget. I also have been evaluating some Wavecor drivers and still have some Purifi on the shelf.
 

voodooless

Grand Contributor
Forum Donor
Joined
Jun 16, 2020
Messages
10,610
Likes
18,748
Location
Netherlands
Agree, if the target was a built-in subwoofer, drivers like the RSS210 would be appropriate. The point of calling it a bass module is that it crosses higher than a typical subwoofer.
Like how high? With the breakup at 5 kHz, It's unlikely to form an issue. The Esoteric has it's first wiggle just pas 1 kHz already.
 
Top Bottom