Ported designs do have their limitations relative to sealed designs. There can be a bit of added complexity getting the tuning right. Sealed designs are much simpler to accomplish.
Does a "more mid-bass strong motor" really exist in practice? I'm not so sure, especially if mid-bass happens to be defined as around 100Hz or so. That's still well within the piston range of the typical woofer/subwoofer drivers.
The 15DS100 has a relatively low Qts of 0.26, a relatively high Fs of 39Hz, and a relatively small Vas of 76 litres. Any traditional tuning will put it in a small vented enclosure that will result in a high value of F3.
If we use a sealed enclosure with Vb = 85 litres, we can achieve the following two sets of low-pass filtered responses. The black solid line corresponds to the response obtained with a series 830uF capacitor. The dashed ligt blue line is the response without the series capacitor. It's clear that adding the series capacitor significantly boosts the low-frequency response of this system. Of course, as its a sealed enclosure, we are displacement limited at a maximum SPL of about 107dB.
With a sealed sub crossed at 70 Hz
A " mid bass" would take over.
Which can be sealed as well.
This would be any normal 3 way design with a woofer.
Since it is on a high pass. It does not need to be ported.
12" 10" 8" midbass make a choice.
Something low Qts with a actual powerful magnet will be fast and accurate and go in a small box
A sub should be crossed low anyways if the distance from the main drivers is far away.
Once you start crossing subs up high around 100 to 150 Hz. Has been done many times.
It just needs to be very close to the other sources.
A " mid bass" would take over.
Which can be sealed as well.
This would be any normal 3 way design with a woofer.
Since it is on a high pass. It does not need to be ported.
12" 10" 8" midbass make a choice.
Something low Qts with a actual powerful magnet will be fast and accurate and go in a small box
A sub should be crossed low anyways if the distance from the main drivers is far away.
Once you start crossing subs up high around 100 to 150 Hz. Has been done many times.
It just needs to be very close to the other sources.
Ok here is an update.
I decided to do some new basic measurements on all speakers, not just MLP but also on axis 30cm and 1meter. Some experiments with room and placements and such.
The findings are that the Revel main speakers have some room crated suck out between 110 and 150. because room is small and f208s are big i cant do anything about that. The low frequencies also seem to get less below 100hz. Therefore I decided to increase XO with the Daytons to about 125 and see how that goes. The mains at 140. it sounded better but the nul around 50 remained. On closer inspection it turns out I made a mistake assembling the diy sealed cabinet of sub number 2. A huge spike at GD gave it away. Turns out the speakon terminal was having a leak. I fixed it today and now both sub perform quite similar. for refrence: both sub cabs are 49x49x51cm (122 liter sealed)
I had to add 2 all pass filters on both subs and one on the mains and after some levelling, now they seem to be happy.
For now im not sure how to go further. I think im quite happy with the Daytons below 50 but above it remains a bit wooly. I think ill embrace GSG's Kevins suggestion to simply keep teh Daytons and add a nice 10 or 12" for more mid bass kick, also perhaps an even higher xo. Anyway, the ultimaxes seem to end sounding good around 130. I also decided to put them in stereo since that made levelling easier.
ChatGPt was extremely helpfull with figuring stuff out with REW. I also somehow made Vituixcad work. Still, a lot of parameters are abracadabra.
Chatgpt advised to have the follow T/S parameters for a 12' replacement
sealed, as small as posisble box (between 25-50 liters ideally)
QTS 0.2 - 0.35
Fs <55
mms <80
BI >15
Xmax min 5 or 6mm
Sd >500cm2
SPL 96>
Vas 40-100
Le <1.5 mH
Is this kind of ballpark? Any other suggestions or corrections?
Atm I have a short list of
Oberon 12NB450
Beyma 12P80Fe/v2 (unavailable at tlhp)
Faitalpro 12FH500
RCF LF 12G301
18sound 12W750
B&C 12NDL76
the max SPL that im looking for is about 110-115 but between 107 and 110 is fine too. Here are some graphs and measurements. MMM and MLP. Mains only and subs only.
this is the rta for levelling and fixing some boomy bass at 44hz, fixed now. I zoomed out to check if the slope is acceptable.
strange rise below 10hz, but no worries
bad sub cab exposed
mmm of current situation of all 4 speakers
larger scale
sub 2 xo125 after cab fix
sub 2 before leak fix
sub 1, the older spec ultimax (the other is ultimaxII)
right main
left main
I decided to do some new basic measurements on all speakers, not just MLP but also on axis 30cm and 1meter. Some experiments with room and placements and such.
The findings are that the Revel main speakers have some room crated suck out between 110 and 150. because room is small and f208s are big i cant do anything about that. The low frequencies also seem to get less below 100hz. Therefore I decided to increase XO with the Daytons to about 125 and see how that goes. The mains at 140. it sounded better but the nul around 50 remained. On closer inspection it turns out I made a mistake assembling the diy sealed cabinet of sub number 2. A huge spike at GD gave it away. Turns out the speakon terminal was having a leak. I fixed it today and now both sub perform quite similar. for refrence: both sub cabs are 49x49x51cm (122 liter sealed)
I had to add 2 all pass filters on both subs and one on the mains and after some levelling, now they seem to be happy.
For now im not sure how to go further. I think im quite happy with the Daytons below 50 but above it remains a bit wooly. I think ill embrace GSG's Kevins suggestion to simply keep teh Daytons and add a nice 10 or 12" for more mid bass kick, also perhaps an even higher xo. Anyway, the ultimaxes seem to end sounding good around 130. I also decided to put them in stereo since that made levelling easier.
ChatGPt was extremely helpfull with figuring stuff out with REW. I also somehow made Vituixcad work. Still, a lot of parameters are abracadabra.
Chatgpt advised to have the follow T/S parameters for a 12' replacement
sealed, as small as posisble box (between 25-50 liters ideally)
QTS 0.2 - 0.35
Fs <55
mms <80
BI >15
Xmax min 5 or 6mm
Sd >500cm2
SPL 96>
Vas 40-100
Le <1.5 mH
Is this kind of ballpark? Any other suggestions or corrections?
Atm I have a short list of
Oberon 12NB450
Beyma 12P80Fe/v2 (unavailable at tlhp)
Faitalpro 12FH500
RCF LF 12G301
18sound 12W750
B&C 12NDL76
the max SPL that im looking for is about 110-115 but between 107 and 110 is fine too. Here are some graphs and measurements. MMM and MLP. Mains only and subs only.
this is the rta for levelling and fixing some boomy bass at 44hz, fixed now. I zoomed out to check if the slope is acceptable.
strange rise below 10hz, but no worries
bad sub cab exposed
mmm of current situation of all 4 speakers
larger scale
sub 2 xo125 after cab fix
sub 2 before leak fix
sub 1, the older spec ultimax (the other is ultimaxII)
right main
left main