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Introduction
A common question I get asked is what horn will work with the B&C DCX-464 compression driver. This popular driver was introduced about five years ago and offers a blend of performance and versatility due to it's dual diaphragm design.
Let's break down what horns work with this driver.
B&C ME90 Constant Directivity Horn
The ME90 is a cast aluminum horn from B&C that accommodates a standard 1.40" compression driver. We use this horn on the 2015 MTM plans due to its low coloration and wide coverage. The horn can be crossed as low as 800Hz based on our testing.
ES-600 Biradial Horn No.1978
The ES-600 Biradial No.1978 accommodates a standard 1.40" compression driver and will load down to 600Hz and also allow for a 800Hz crossover point. This horn will offer more clarity and upper treble output compared to the ME90 mentioned earlier. Coverage is also wide in the treble region making it suitable for small, medium, and large listening spaces. Listening distance can be as close as 2m if pairing with a 10" woofer using close driver spacing. An example of this is shown below. (Note that the super tweeter is entirely optional)
B&C ME464 Constant Directivity Horn
The DCX-464/2 does well on larger horns due to it's low FS of only 240Hz. It goes without saying that there is the dedicated ME464 horn on offer from B&C, but we've never tested this horn or heard the overall sound quality, so we can't say if it would be good for home listening.
Sabourin Horn Horn No.1293
The Sabourin Series is our own large format exponential horn dedicated for home listening, offering low coloration and excellent off-axis coverage.
Specifically, size variant No.1293 uses a 2.00" x 2.00" square throat which when combined with the adapter allows for a standard 1.40" compression driver such as the DCX-464.
The adapter is shown below and is included in the plans in .STL or .iges file format.
The Sabourin Horn No.1293 offers a 300Hz cutoff frequency and has a 50cm x 50cm horn mouth which is similar is size to the B&C ME464 horn mouth size.
Details on the the Sabouring Horn No.1293 can be found at the product page, blog post. and walk-through video.
We do not offer a turn-key plan set for the 1293 + DCX-464 combo, so you'll have to integrate this yourself. For support on crossover design we offer our Crossover Video Training Series.
ES-450 Biradial No.1993 (1.40" Version)
The ES-450 Biradial offers wide off-axis coverage even in the upper treble allowing use of the DCX464 driver. The horn uses a standard 1.40"" compression driver mounting.
We offer the 3D CAD files for DIY here.
For custom builds please contact. (We do not have a product page yet for this product)
ES-290 Biradial with 1.40" Throat
Unfortunately this is not a product that exists.
Adapters
The DCX464 can be adapted up to a standard 2.00" throat using an adapter such as the Eminence HA14-2.
In fact, you can order the DCX-464 with the adapter pre-mounted. This model is the DCX-462.
2.00" Horn Options
Moving up to the 2.00" throat size opens up a variety of horn options, however it must be kept in mind that the larger 2.00" throat will cause a narrowing of the coverage pattern in the 10kHz region. Expect around a 60 degree listening window compared to 80 degrees with the 1.40" throat horns. However, I will list the available horns for those still interested.
ES-450 Biradial No.1994 (2.00" Version)
The ES-450 Biradial No.1994 uses a standard 2.00" throat which necessitates the use of a dedicated super tweeter due to the narrowing of directivity in the 10kHz region. This is why the design includes an extension out the back to mount a super tweeter which ensures critical time alignment.
We offer the 3D CAD files for DIY here.
For custom builds please contact. (We do not have a product page yet for the physical product).
The ES-450 Biradial No.1994 is used on our Speaker System No. 2095.
ES-290 Biradial No.1670 (2.00" Throat)
The ES-290 Biradial No.1670 is only available in a 2.00" throat.
For the 3D CAD models click here.
ES-290 Biradial No.2376 (2.00" Throat)
This latest version loads flat down to 300Hz and has similar lower midrange authority as the highly coveted Yuichi A290. Currently this model is only available as a finished build or included when ordering a turn-key build.
To purchase the horns click here.
The ES-290 Biradial No.2376 is used on Speaker System No.2087.
Conclusion
I've used the DCX-464 as an example on how to match with various horns. This blog post can serve as a general guide for all 1.40" compression driver models. Most modern medium and large format compression drivers come standard in the 1.40" throat with alternate models available adapted up to the 2.00" throat size. Another example on this is the RFC ND950 1.40 and ND950 2.0 variants, with 1.40" and 2.00" throats respectively. Below you can see the same driver simply adapted to the larger throat size using a conical flare.
If you are unsure of a compression driver's capability then please look at the impedance sweep in the compression driver's published data.
The hand drawn arrows represent the maximum bandwidth of a compression driver both in the low frequency (Fundamental Resonance, aka FS) and the upper treble (diaphragm mechanical breakup) where the impedance curve starts to become uneven with sharp irregularities.
Other things to note
We only recommend buying new compression drivers. It is very easy to over-stress a compression driver with high SPL which will degrade the sound quality. Therefor there is high risk in buying used especially if the history of the driver is unknown. This especially becomes true when buying TAD compression drivers which are manufactured to higher tolerances and therefore are less forgiving to abuse.
It has been my experience that most compression drivers are not suitable for home hifi listening simply because they have been engineered for high SPL and serviceability. Sound quality is a concern during development but it is not the number one priority.
Some companies offer specific models which are designed specifically for sound quality. Speaking with engineering managers from both SB Audience and B&C I was able to make a short list of drivers and confirm with our own testing and evaluation. (no affiliation)
SB Audience
- Our test data can be found here.
- Our test data can be found here.
B&C Speakers
- Our test data can be found here.
- Our test data can be found here.
- Our own test data can be found here.
- Our own test data can be found here.
One problem with Active
Compression drivers require a small fraction of a watt to reproduce SPL levels for home listening. This means that in an active setup the amplifier will be barely working to reproduce the required output. This puts the amplifier completely into it's own noise floor. The end result is a cold, clinical, and harsh sound. Side note, this is also the scenario experienced by those trying 8" full-range drivers with solid state amplifiers. In general, it is critical to pair high efficiency drivers with low gain amplification. We are literally talking about an amplifier with an output of only 1 or 2 watts. Alternatively you can pad the compression driver down with a fixed resistor L-Pad. We suggest at least a -10dB L-pad to bring the amplifier up out of the noise floor. Even the quietest amplifiers such as those from Hypex require padding.
Passive vs Active
It's my position that nothing beats a really good passive crossover. When building one of our turn-key DIY plans, it is always advisable to build the passive first, then attempt fully active to see if you can exceed the sound quality of the passive. It is more challenging to implement active successfully than it is to follow the build plans provided.
It is my plan to introduce a dedicated page on my site for Frequently Asked Questions. So I will leave this blog post here for now.