Placing a separate tweeter high on the door and a mid-bass driver down low has become universal for car sound - even in new cars. The split approach has the advantage that the more directional high frequencies come from a tweeter mounted closer to ear level - and that has positive implications for staging. Using splits rather than a two-way coaxial speaker also means that a proper LC (inductor, capacitor) crossover can be used - coaxials normally have room only for a single capacitor.
On test here are the Altronics C9302 splits. Budget priced at $179 (and on special now at $129) they are amongst the cheapest ways of getting a pair of splits into your car. But what's their quality like?
The System
The mid-bass units have a nominal diameter of 165mm (6.5 inches), but the actual effective cone area is much smaller than this at 120mm (4.7 inches). They have the typical rolled-edge suspension, a large magnet and a pale green cone that appears to be made of some type of plastic. The voice coil diameter is 25mm, and the dust cap doesn't make any attempt to inflate this diameter - it's 25mm in diameter as well. Wire grilles and mounting rings are provided.
The tweeters are of dome construction, being a nominal 25mm in diameter. Two mounting systems are provided with the tweeters - a flush mount suitable for integration into a door lining, and a surface mount that could be used to locate them in the sail areas. Both of these mounts look good - they're not the cheap and nasties you could expect with a system selling at this price.
The crossovers come mounted in boxes (here shown opened), complete with gold-plated screw-down terminals. Solid cored inductors are used and a three-position switch is fitted to allow tweeter trimming (0, +3dB and -3db). The connections for the amplifier, tweeter and woofer are clearly marked on the crossover. In addition, an extensive amount of hardware is provided, including (very light duty) wiring.
Testing
We spent a great deal of time testing, for we had some problems. But before we describe what we found, a word about testing this type of speaker system. The sound from (especially) the bass end of the sound spectrum is very much determined by the enclosure design. Even the best woofer will sound terrible if driven sitting on the bench - and it might also sound pretty bad if mounted in a box that's too small or too large. At least with splits (most frequently mounted in doors) you don't have to worry too much about port diameters and lengths - the enclosure is effectively sealed. But the pattern of airflow behind the mid-bass unit will change its response, as will the volume within the door, how much (or little) factory sound deadener is present, and the number and magnitude of any air leaks through and around the edges of the trim.
As a result of these variables, we performed two tests on the system. The first involved the mounting of the system in the doors of a Nissan EXA. The depth of the bass drivers (about 75mm) meant that spacer rings had to be used to move the speakers out of the doors a little. We originally used purpose built door pods (covered at "Making Door Pods" ) then reverted to using MDF rings with the complete driver covered on each door by VR Commodore factory door pockets and speaker grilles. The tweeters were mounted flush in the lining high on the doors, with the crossovers located on the kickpanels in the cabin (ie both tweeter and woofer pairs were run to the crossovers).
Mounted in this manner the sound was adequate - noticeably better than would be gained with dual-cone older factory-style speakers, for example. But the music did lack some mid frequencies, and we also thought that the tweeters didn't sound particularly sweet. It was almost as if the tweeters had some sharp peaks in their response. We modified the door mounts to better seal off the enclosures from the front of the speakers and made some other mounting changes, but the sound still lacked depth.
We then removed one channel of the system from the car and mounted it in a 21 litre MDF enclosure. This was lined with acoustic wadding to prevent reflections and was completely sealed. In this more formal enclosure the system sounded much better. However, extensive testing showed a number of traits. While the sensitivity of the system is not listed, we'd suggest that on the basis of this testing, it is quite low. Lots of amplifier power is needed to gain high SPLs - although that's something that the system seems quite happy handling. Peak power handling is quoted at 100W RMS, and our testing showed that this was the case. So running this combination straight from a low-power head unit will not give much SPL.
You're also not going to get really deep bass from a cone area of just 113 square centimetres (not unless the driver's in a very special box, anyway!) and you'd certainly not want to rely on these little drivers to provide all the bass component in a car. However, properly mounted, the midrange sounded much better, and the treble - while at times a little harsh - could be modulated in output with the three-position switch to achieve a satisfactory result.
Conclusion
With absolutely all of the mounting and wiring hardware included, this split system looks good and in general sounds fine. The actual sound that you get will be largely dictated by the mounting arrangements that you make, but working together with a sub, this cheap system has the power handling and sound output to make a good upgrade over typical factory door speakers.
Contact:
www.altronics.com.au
