I've been testing OB in an active 4-way configuration where the low bass is covered by two 12" sealed Rythmik subs, and the OB has two 10", an 8" for mids and a tweeter.
The twin 10" are Beyma 10G40 which I had from a previous project. I'm liking the sound, but need to cross them no lower than 70Hz and while the bass is very well defined I still miss a bit of impact. I'm thinking I might need more Sd on the midbass. Does this sound like a good diagnose?
I see most OB use 12" or 15" drivers, sometimes using two per side. I believe often those are used without subs below, though. The recommendations seem to be for drivers with low fs (30-35Hz), high Qts (Emminence Alpha 15A has 1.2), Xmax of 8-10mm.
Looking at pro drivers, the ones that satisfy the fs and Xmax criterias and have the highest Qts are 18". Using one 18" per side would allow crossing from the sub around 40-50Hz, and would almost double Sd of twin 10". But then I don't often see 18" for OB midbass so maybe I'm off. Hence the ask for help 🙂
Here are the two 18" I've narrowed down to:
Today the midbass runs up to 500Hz. Would love to get input from experienced users regarding using a 18" driver vs 15" or even twin 12" for this application and if there are better suited drivers than the ones I listed. Maybe I'm giving high Qts more value than what it deserves?
Thank you!
The twin 10" are Beyma 10G40 which I had from a previous project. I'm liking the sound, but need to cross them no lower than 70Hz and while the bass is very well defined I still miss a bit of impact. I'm thinking I might need more Sd on the midbass. Does this sound like a good diagnose?
I see most OB use 12" or 15" drivers, sometimes using two per side. I believe often those are used without subs below, though. The recommendations seem to be for drivers with low fs (30-35Hz), high Qts (Emminence Alpha 15A has 1.2), Xmax of 8-10mm.
Looking at pro drivers, the ones that satisfy the fs and Xmax criterias and have the highest Qts are 18". Using one 18" per side would allow crossing from the sub around 40-50Hz, and would almost double Sd of twin 10". But then I don't often see 18" for OB midbass so maybe I'm off. Hence the ask for help 🙂
Here are the two 18" I've narrowed down to:
- Beyma 18LX60: Qts: 0.48, Xmax: 8mm, fs: 35Hz, Sd: 1320cm2, Sensitivity@50Hz: about 89-90dB, impedance@50Hz: about 16 ohm
- Faital 18HP1010: Qts: 0.40, Xmax: 9.75mm, fs: 35Hz, Sd: 1207cm2, Sensitivity@50Hz: about 93dB, impedance@50Hz: about 27 ohm
Today the midbass runs up to 500Hz. Would love to get input from experienced users regarding using a 18" driver vs 15" or even twin 12" for this application and if there are better suited drivers than the ones I listed. Maybe I'm giving high Qts more value than what it deserves?
Thank you!
If you wanna get some impact from ob best is lots of sd.
I had bms 18n862 on ob, it was kind of good but there was limit playing louder, rear voicecoil vent started to make buzzing noise.
AE seems to be most silent on that approach, heard that they start to spit thru voicecoil and phaseplug when they are in sealed enclosure.
There are some 18" which can go to 400hz, on ob you need to cut lower end away cause excursion start to affect upper range.
And using single hardcore 18" you need to connect it to something heavy, 40-50kg wasn´t enough for bms 862.
PPSL could make a difference but it limits upper end
So lots of 15"/18 4pc per side so excursion stays under 2-3mm
I had bms 18n862 on ob, it was kind of good but there was limit playing louder, rear voicecoil vent started to make buzzing noise.
AE seems to be most silent on that approach, heard that they start to spit thru voicecoil and phaseplug when they are in sealed enclosure.
There are some 18" which can go to 400hz, on ob you need to cut lower end away cause excursion start to affect upper range.
And using single hardcore 18" you need to connect it to something heavy, 40-50kg wasn´t enough for bms 862.
PPSL could make a difference but it limits upper end
So lots of 15"/18 4pc per side so excursion stays under 2-3mm
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Thanks for the input!
How low were you playing the 18n862 in OB?
My 2x10" xo at 70Hz can play loud enough without buzzing, so thinking you either play much louder or cross much lower, or both?
I plan to place the driver on a swing, maybe with additional weight behind the magnet.
I guess you are saying that 500Hz is too high for a 18" driver.
mmm...4x15" or 4x18" per side is not an option. I could talk myself into 1x18", or 2x15" or 2x12", plus subs.
I use two Beyma sm115 driver per side for bass in my open baffle. Plenty of impact and dig fairly low in the room.
LOUDSPEAKER SM 115/N 8 OH
I cross them at 22hz 220hz. To a beyma 12mi100
LOUDSPEAKER SM 115/N 8 OH
I cross them at 22hz 220hz. To a beyma 12mi100
I tried AE ob 15 drivers. They look great but for me I would get over excursion if I tried for any volume. The beyma pro audio driver is more controlled and plays a lot louder
You´re gonna end up sealed
i used 862 down to 30hz, it was lowest room mode and near fs so no point trying lower.
and i had this type of raised cosine filter boosting that.
OB is nice and fun but too problematic, i would take panel/electrostat before dynamic driver OB
Thank you!
I looked at those too, but thought Qts might be low. Evidently it is not!
So you have subs below 22Hz, the SM115 22-220Hz, and 12MI100 from 220 to how high? Is that a 5-way system?
Yours is the second post suggesting my hopes for 500Hz xo for the midbass is probably not good. Would you mind sharing why you xo at 220Hz with the SM115?
2x15" from these, qts can be what ever if active, would not go over 0.5, too weak.
i would look models which has vented spider, maybe less buzzing.
models which has large magnet vent tends to resonate 300-400hz so bad you can hear it to listening spot. pretty much all BMS neo models and 18sound 15nmb420.
maybe 100cm baffle could help and some rear acoustic.
Got it.
What's your take on the two 18" shown on post #1 and the SM115n mentioned above?
Reflector audio
check these out, P18, P1805 and P15
I believe those to be faital 18FH500, quite priceworth driver but dipping around 300hz.
would not point those maybe buzzing rear ends towards listener, but looks cool anyway
Maybe theres some diy measurements online how bad that 300hz dip really is.
Theres many more choices to cover upper range with 15"
drivers with small voice coils has smaller air volume behind dustcap, so noises might be higher, hopefully above xo point.
Removing dustcap can make it silent but you lose some sd
check these out, P18, P1805 and P15
I believe those to be faital 18FH500, quite priceworth driver but dipping around 300hz.
would not point those maybe buzzing rear ends towards listener, but looks cool anyway
Maybe theres some diy measurements online how bad that 300hz dip really is.
Theres many more choices to cover upper range with 15"
drivers with small voice coils has smaller air volume behind dustcap, so noises might be higher, hopefully above xo point.
Removing dustcap can make it silent but you lose some sd
220 hz because my midrange goes that low. I tried a higher crossover and didn’t like the sound as much.
The 12mi100 Mid range goes from 230 to 1800hz. From there up a horn loaded ribbon driver takes over.
The bass drivers have almost limitless amplifier on tap. The midrange and tweeter require much less power.
IMO a sub isn’t needed for almost all music except some electronic and hip hop. For home theater I would change that to say a sub is a nice addition.
The 12mi100 Mid range goes from 230 to 1800hz. From there up a horn loaded ribbon driver takes over.
The bass drivers have almost limitless amplifier on tap. The midrange and tweeter require much less power.
IMO a sub isn’t needed for almost all music except some electronic and hip hop. For home theater I would change that to say a sub is a nice addition.
Thank you!
Is your system active/passive xo? If active, digital and room correction too?
Interestingly usspeaker.com notes the sm115n as having "extended midrange that is detailed", hence my question about crossing it "low" at 220Hz.
I have B&C 8PE21 for mids that struggle getting to 250Hz. I'm running them baffleless, so maybe I try a baffle and see how the sound changes.
BTW is the horn loaded tweeter also dipole?
Active crossover. Surprisingly with these drivers I only level match and delay no equalization.
My midrange is a 12 inch I assume that’s why it can reach a bit Lowe than yours. The 12 has very narrow dispersion at high frequencies so the sweet spot for listening is small. Maybe a 10” would be a good compromise
The tweeter is closed on the back. I have a pro audio bulletin tweeter firing backwards out of phase. It’s crossed fairly high with a simple first order filter off the main tweeter.
My midrange is a 12 inch I assume that’s why it can reach a bit Lowe than yours. The 12 has very narrow dispersion at high frequencies so the sweet spot for listening is small. Maybe a 10” would be a good compromise
The tweeter is closed on the back. I have a pro audio bulletin tweeter firing backwards out of phase. It’s crossed fairly high with a simple first order filter off the main tweeter.
Thinking of your original question. I had been following convention and used high qts drivers from the eminence alpha 15 beta 15 and then the acoustic elegance dipole 15. Spending more didn’t get me what I was looking for. I wanted to try a more powerful low qts driver and came across the sm115 drivers used. They give me what I wanted and I experimented no further. I’m sure there are many good lower qts drivers that would work well