diyAudio.com - OldWiki Archive

Introduction: the market is now very competitive

In the past, choices were much fewer and most diyers built Shiva and Tempest subwoofers
or clones, with a few choosing other drivers like Lambda or XLS. Now the market is much
more competitive. New drivers with more advanced motor designs are entering the market
with very attractive prices. The most impressive drivers offer various means or reducing
distortion, utilising shorting rings, XBL^2 motors or other systems aiming to achieve a
flat BL curve, which means distortion is lower with higher excursions. One brand also
offers a diy servo kit!

If you are building a fairly conventional subwoofer, I suggest that you look past the now
outdated designs.

Dilemma: to go with a diy favourite or a new driver?

If you haven't heard many different diy subwoofers, there is some comfort in using drivers that everyone raves about. The Adire Shiva comes to mind. While it's a good idea to go with tried and trusted brands and drivers, it isn't necessarily a risk to try a driver that isn't featured on 9,000 diy websites!

Importing vs buying local

In countries outside the US, it is often a good idea to consider importing. Often this results in a better deal than buying what is available via local dealers. You should check with the particular brand of driver you want if they have local dealers, and if they will ship to your location. Some dealers which don't normally ship internationally may do so if there isn't a local dealer in your country.

Don't be one of the many who say "driver XYZ isn't available in my country!" You can get almost any driver to almost any country! Don't be put off by shipping. Get a quote and compare the total cost to what you can get in your country. And if you are one of the lucky ones in the US, don't complain about shipping, you don't know how good you guys have it! In Australia we pay a lot more than you do!

TS parameters - which ones are important?

The first three parameters to look for are fs (free air resonance), Qts (Quality factor for driver) and xmax (maximum linear excursion). A driver suitable for conventional sub applications will typically have a low fs ~ 20 Hz, Qts ~ 0.4 and an xmax of at least 12mm. If a driver has parameters which vary to this significantly, you will have to model it to see if it can be made to work. Drivers with a Qts of 0.5 or higher typically only work in sealed boxes and drivers with a low Qts such as 0.2 will require additional eq in a sealed box as they will have early roll off and a high F3.

What should I look for in a driver?

* suitable parameters for your application:
For a conventional design, this is best determined with some simulations. Some drivers need a large box, others are designed for a small box.
* low distortion motor system:
The better drivers use various methods reduce distortion. These included the use of an extended pole piece, shorting rings and various means to control the linearity with respect to excursion. While it is better to look at actual distortion measurements than the features of the motor system, this information is not always available.
* appropriate materials:
Foam in surrounds is a problem in some areas regarding longeivity; while makers of sub drivers, (notably Dan Wiggins of Adire audio) claim foam has now been improved and has overcome past issues, caution is advised if you live in an area where foam doesn't last long. Cone material is not likely to be important, as long as it is well designed.
* rigid basket:
In general, cast aluminium baskets are superior to stamped steel due to their rigidity. They are also more appropriate for open baffle dipole use due to their aerodynamics which reduces turbulence.
* leads:
Some early high excursion drivers had lead slap with high excursion. The leads which run from the speaker inputs to the voice coil can hit the cone, however this is not likely to be a problem with most current drivers. Some have these leads woven into the spider.

Keep in mind that there are many ways to design a subwoofer. The driver you want may not have the most suitable parameters, but you can still work around this and make it to work. On the other hand, if it doesn't have sufficient excursion to meet your goals, there isn't a way around this.

Recommeded drivers

* [Rythmik Audio Servo kit]
This kit is unique as it is the only diy servo offering available. This is likely to be one of the most articulate subwoofers available. Highly recommended.

* [Dayton Subwoofer drivers]
Dayton have three drivers worth considering. Their standard driver [12" DVC SERIES SUBWOOFER] is a Shiva clone and can readily be used for a value for money subwoofer. However, considering the range of subwoofers now available, it would be worth spending just a little more to go for the more articulate reference series subs, such as the [Dayton 12" reference sub]. It has shorting rings, an aluminium cone and a cast basket. In short, a much more attractive driver for not much more money. The [Titanic] also has a shorting ring but more excursion, and comes in a 15" version as well.

* [TC sounds]
TC sounds are a well-established name in subwoofer drivers. All of their drivers have high excursion and their reference driver has a flatter BL curve than Adire XBL^2 drivers! The TC2+ comes highly recommended. It has a shorting ring and slightly better distortion performance than the XLS.

* [Exodus Audio]
Exodus Audio have some new drivers with XBL^2 motors, apparently intended to be similar to older versions of the Shiva and Tempest, but with superior performance. [Exodus CX-12 & CX-15].

* [Ascendant Audio]
Ascendant Audio entered the market with a range of subwoofers with XBL^2 motors at lower prices than anything available from Adire with this level of performance. They are currently developing a series of drivers which will attempt to offer the same benefits as the XBL^2 system. There is every reason to believe that their next line of drivers will be excellent value when available.

* [Adire Audio]
Arguably the most innovative company designing subwoofer drivers available to diy enthusiasts, Adire are a diy champion. Their XBL^2 motor system has set a benchmark which now represents a standard that most other drivers are compared against. This technology enables them to make ultra high excursion drivers which have low distortion at close to their xmax. The [Tumult] is their statement driver.

* [RE audio]
RE Audio have drivers ranging from affordable entry level to drivers which are the ultimate in output (MT series) and the ultimate in fidelity (XXX series). The XXX series drivers are similar to the Adire Tumult series.

* [Acoustic Elegance]
AE, formerly known as "Stryke Audio" have always been exceptional value. Their AV series subwoofers achieved a level of build quality and output capability unmatched at such a low price. This range was developed in conjunction with TC sounds. They also have a HE range currently in the works. The HE15 was available in the past and is well regarded as an extreme driver, also based on a TC sounds design. Of particular interest to many is the IB15 which is a Lambda Acoustics design. It is a 15" driver designed for infinite baffle use.

* [Peerless]
The Peerless XLS has long been considered one of the best subwoofer drivers available. It is featured in many commercial and diy subwoofers. It is used by Linkwitz in the much esteemed Orion dipole speaker. Unlike many sub drivers, this driver can be crossed fairly high.