[JohnR]

This post lists drivers for DIY open baffles. The list cannot possibly cover every driver that "could" be used in an OB configuration, so it focuses on drivers that are proven or popular for DIY use, or otherwise interesting. Drivers must also be readily available new to be listed.

Please post in this thread if you have a suggestion that is not already here or additional information that should be added to this post.

Update: I've tried to order each section roughly by cost. Just thought it would help people looking for drivers to focus in based on their budget.

Fullrange and mid-tweet

While any fullrange driver could be put onto an open baffle, this list mostly includes only those specifically suited for it, meaning high-ish Qts or that were recommended by members. Many have fairly low Xmax so you may want to supplement the bass when used on open baffle. Because of this, the list now includes full/wide-range drivers that have been recommended for use as a mid-tweet.

• The Tymphany TC9FD18-08 (also known as Vifa and Peerless) is cheap (~USD10 USD23) and has a fairly smooth extended response. Used in the Manzanita projects as a mid-tweet. It's available in lots of places worldwide. Note: if building to a published design, be sure to use that specific version and not some other TC9. Note 2: a lot of Tymphany drivers have been disappearing from the DIY market, so it's possible this one will too.
• The Wild Burro Betsy is quite inexpensive (USD125/pair) for a driver intended for OB use.
• The Ciare CH250 was recommended in this thread - "The Ciare's are running without any filter network and sound surprising good". (To be honest, the response looks pretty ragged to me, although it is cheap.) Available from audiovideoparts (IT).
• The Visaton B200 was an OB experimentor's favorite for some time although the price has gone up a lot since then. Currently available from Parts Express (US), Thomann (Germany, ships worldwide), Solen (CA), Sound Labs Group (AU), Impact Audio (UK), ...
• Lii Audio sell a range of drivers suited for OB, ranging from 8" to 15".
• Commonsense Audio sell the Audio Nirvana range of drivers. As a general rule, only the Alnico magnet drivers seem readily suited for OB use, with Qts in the range of 0.5 to 0.8. (The Ferrite and Neo series have much lower Qts - around 0.2 to 0.3 - suggesting use in back loaded horns, unless used only as a mid-tweet with helper woofer.)
• "The Lowther PM6A works well in open baffle, and to my ears, sounds much better than any of the Fostex or Audio Nirvana drivers I tried." - glynnw. Also used in Nelson Pass' Slot Loaded Open Baffle. Available from Lowther Loudspeakers (UK). Low Qts.

Woofers

There are two schools of thought for dipole woofers. One is that high Qts (0.7 or higher) is better as it tends to counteract the dipole roll-off. Often, these are "pro" style high sensitivity drivers and a low rolloff is chosen (eg. single inductor) to match a midrange or fullrange driver in the 200-300 Hz range. The other school of thought is that Qts doesn't matter so much because active EQ will be used.

Note that with the exception of the GR Research and Acoustic Elegance woofers, these woofers won't really deliver sub-bass. For dipole sub-bass, high-quality subwoofers can be used, often in a dual-opposed arrangement, provided they have low self-noise.

• MCM Electronics sell a number of cheap drivers that could be used, here is a curated list by Monte Kay.
• Parts Express have a number of high-Qts GRS brand woofers: GRS woofers and subwoofers in 10, 12, 15" sizes. (Ed note: some of these are really cheap, so keep expectations realistic...)
• The Goldwood GW-1558 and GW-1858 are recommended in this thread. (A lot of coneage for not much dollerage!).
• The Visaton WS 25 E is high QTS 10" driver and very inexpensive. Available from: Parts Express (USA), Soundlabs Group (AU), ...
• The JB Systems SP15/250 has been suggested in this thread and may be a good inexpensive option for European experimenters. For example (BE).
• Omnes Audio (DE) carry the Redcatt OBW 15 which is designated as being suited for open baffle. (Note that earlier listed driver OBW 1006, OBW 1206 and OBW 15PA appear to have been discontinued.)
• The Eminence Alpha 15A is a popular budget choice for OB woofers however the price has gone up and depending on your location the SB Audience woofers (below) may be a better choice. Available from: Parts Express (USA)...
• SB Audience make two woofers specifically billed as suitable for OB use, the  BIANCO-12OB150 and BIANCO-15OB350. Available at Madisound (US), Wagner Electronics (AU), .... The 15OB350 got a good review.
  
• The Morel MW-1075 seems to be related to the PAP1075 (Pure Audio Project, no longer available separately) but with lower Qts. Available from: Parts Express.
• Sb Acoustics make a 16-ohm woofer billed as suitable for OB use, the SB34NRX75-16. I haven't seen any user reports.
• GR Research sell the SW-12-04, SW-12-08FR and SW-12-16FR open baffle servo woofers. User reports are very positive but they must be used with the matching amplifier (necessary, you can't use just any amplifier with servo woofers).
• The Faital Pro 15PR400 is used in Troels Gravesen's OBL-15 and receives favorable reports. In the USA they are quite expensive so importing might be cheaper. (TBH in general the price seems to have gone up everywhere.) Available from Parts Express or 4 ohm version (USA), DJ City (AU), Lean (UK), ...
• Acoustic Elegance make a number of drivers specifically for open baffle use, in particular the Dipole Woofers and the LO Woofers. Note: AE typically build to order and have a reputation for long wait times, so be sure to check on this before completing your order. Some time in late 2023, the price jumped about 60% so it's harder to recommend them now.
  

Midrange

Almost any cone driver can be used as a dipole midrange. Note that as frequency rises, the radiation from the rear of a cone driver is disrupted by the motor/basket structure, limiting the top of the usable range if you want to maintain a dipole radiation pattern. This list therefore includes only drivers that are largely symmetrical or distinguish themselves in some way.

• Parts Express is now (Q3 2020) carrying a range of cheap(er) BG look-alikes, including the PT5010-8 which appears to be similar to the Neo10 but cheaper. Some online reports suggest that measurements are not as good but do your own research.
• Radian have recently (2023) announced the LM10n which is about the same size as the discontinued BG Neo10. They are pricy.
  

Tweeters

The following list includes only dipole tweeters. Some drivers listed, specifically some AMTs, are not designated as dipole tweeters but are known to be usable as dipoles or at least open-back by removing the back chamber or foam pad/backing.  Some drivers listed are quite tall so be aware that tall tweeters will have reduced vertical dispersion.

Note that other drivers can be also be used in an open baffle speaker. Sometimes a "back to back" configuration is used. Some DIYers have used waveguide tweeters in order to maintain controlled directivity in the front hemisphere while allowing the radiation in the back hemisphere to fall to zero.

• Parts Express is now (Q3 2020) carrying a range of cheap(er) BG look-alikes, including the PT2522-4 which appears almost identical to the BG Neo3 but at USD30 USD40 apiece would be the new budget champ for dipole tweeters, and the taller PT6816-8, which is an interesting candidate for a line array mid-tweeter.
• The Beston RT002A tweeter is available in a "dipole" version from Parts Express. I haven't seen any measurements of dipole performance but this driver seems to be the current budget champ for experimenting with dipole tweeters.
• The Bohlender Graebener Neo3PDR (the former budget champ before the price more than doubled overnight) is now unavailable. However an alternative (not made by Bohlender Graebener, apparently) is available from GR Research.
• The Dayton Audio AMTPRO-4 has removable foam pads on the back and so can be used as a dipole. Vertical dispersion is very limited.
  
• The Aurum Cantus AST2560 and AST25120 have a piece of felt glued on the back that is easily removed. (AST2560 verified, AST25120 appears the same in photos.)
  
• Radian make several planar drivers that look suitable. These are a relatively recent addition to the market, but Hollis Audio Labs has been using some.
  
• ESS in the US are re-making the Heil AMT. Some time ago there were three versions but it appears that now there is only the "large" model. There doesn't seem to be much in the way of definitive reports from end-users and the manufacturer doesn't supply any measurements at all, so proceed with caution. They may be available from Solen (CA) but as of January 2024 they are out of stock.
  
• Beyma TPL-150 can apparently be used as dipole by removing the back chamber. I'm not sure if this is a simple process or not, do your own investigation...
• Mundorf make a range of pricy but seemingly very nice dipole AMT tweeters. Link is to Mundorf online store, they are also available at: Madisound (USA); Hifi Collective (UK); lautsprechershop.de (Germany). NB some links include non-dipole tweeters.

Drivers that are specifically NOT recommended

• Aurasound NSW1 and NSW2. While these are open at the back, the driver structure forms a tunnel that resonates at 1.6 or 2.2 kHz, making them unusable for OB (unless you severely limit the passband).
  

Discontinued drivers

These drivers have been moved out of the main list, but kept for reference in case they come back.

• The Fane Sovereign 15-300TC is an interesting candidate (15") that has seen good reports. The 12" Sovereign 12-250TC is another. As of January 2024, these may have been discontinued as none of the previously listed vendors have stock.
• The Monacor SP-382PA is suggested in the thread as a good option esp in Europe. As of January 2024, it appears to no longer be available.
• The Tymphany Peerless SLS-P830669 (often referred to as just Peerless 830669) is used in the Manzanita 12" version. Like many Tymphany drivers these seem to be disappearing from the DIY market (minimum order qty at Parts Express is 100 units, for example). Currently still available at Wagner Electronics (AU), Sound Imports (EU), ...
• The Bohlender Graebener Neo10 was off the market for a while but is currently available from Parts Express. As of July 2019 however, the price has nearly doubled (to USD370) so it's hard to recommend. As of December 2020 the Bohlender Graebener Neo10 appears to no longer be available.
• The Raal Dipole 140-15D seems like it might be discontinued as it's no longer on their website although still available as a special order from Madisound (USA). It's very expensive so not many user reports.

[AJinFLA]

Hi John,

For passive woofers sytems, MCM has a number of very inexpensive drivers that can be used, some measured independently here http://www.mfk-projects.com/my_projects/Projects%202015/MCM%20woofers.html. Many of their house brand drivers have much higher Qts that spec'd, including some of the cast frame pro drivers.
At Parts Express, some Goldwood and GRS woofers also have high Qts (spec'd) that can be used passive.

cheers,

AJ

[glynnw]

The Lowther PM6A works well in open baffle, and to my ears, sounds much better than any of the Fostex or Audio Nirvana drivers I tried.  Nelson Pass uses this driver in many of his OB designs.

[JohnR]

Thanks guys, list updated 

[Fjendbo]

The German dealer OmnesAudio have a 10" (OBW 1006), a 12" (OBW 1206) and a 15" (OBW 15PA) woofer for OB.
https://www.oaudio.de/Lautsprecher-Selbstbau/Lautsprecher-Chassis/Omnes-Audio/OA-Tieftoener/

Thought they might be relevant for EU members

[Fjendbo]

And the Monacor SP-382PA could also be a possible candidate for an OB woofer: https://www.monacor.com/en-gb/monacor/products/components/speaker-technology/pa-bass-speakers/sp-382pa/

Can be found at various dealers in Europe. Don't know about the US.

[JohnH12]

There are a number of high QTS GRS woofers and subwoofers that work well OB https://www.parts-express.com/brand/grs/466

[JohnR]

Thank you for all the recs, I will update the first post when I get a chance.

[Bumpy]

Why are there no cone tweeters recommended?

[ricmon]

Guys this is a bit off topic but I'm interested in finding a smoother sounding compression tweeter driver for my Emerald Physic's 2.3's.  Any suggestions?

thanks
Ric

[JohnR]

Guys this is a bit off topic but I'm interested in finding a smoother sounding compression tweeter driver for my Emerald Physic's 2.3's.  Any suggestions?

thanks
Ric

Can you start a new thread for that?

Why are there no cone tweeters recommended?

I dunno... I don't think I've seen a cone tweeter used in an OB... did you have some specific recommendation?

[PDR]

Before opening the backs of the compression drivers of the P-Audio in the V series,
Danny used a dome ......guess that made them bipole for the highs....for the rear.

[PDR]

Oops.....just noticed you said CONE not DOME.....

Dont all the full range driver O.B. use a cone.....or wizzer for tweets?

[JohnR]

Yes, I guess if you use a fullrange driver it's also acting as a tweeter. At tweeter frequencies the output from the back is quite attenuated though.

[JohnR]

I've added a few more drivers to the list, feel free to post if you have additional recommendations.

[FullRangeMan]

Kevin at http://www.glowinthedarkaudio.com/audionirvana.html
have tested some Nirvana ferrites notedly Classic10CF that was performed a very open sound as OB with a small tube amp in a previous version of this review, at the current price the Classic10CF are good value.

[JohnR]

Added Lii Audio, any others that have come up lately to include in the list?

 

[Thue1]

My few cents on a OB sub driver which I'm using in a Ripol setup with 4x15".
Can only say they play magnificent and go easily down to 20 hz. Applying DSP correction and mainly use them up 80 hz. In my system since 2011.


JB Systems SP15/250 @ 40,- Euro's a piece.
Fs: 31 Hz
Vas: 238 l
Qms: 5,9
Qes: 1,3
Qts: 1,08
Sd: 983,7 cm2

BR
Carsten

[JohnR]

Thank you, added it to the list of woofers.

Removed Pure Audio drivers as they are no longer sold separately.

Moved kits to this thread.

[JohnR]

Added woofers from Omnes Audio, GRS, Monacor. Thanks for the suggestions!