Making the Akai DPS16 Less Noisy

When I first got my Akai DPS16 multitrack recorder I was happy with the basic operation but unhappy with the amount of noise generated by the 20 GB internal IDE hard drive (mostly, ticking sounds from head seeks while recording) and also the whine of the internal 40mm fan. That same afternoon I got a cabinet from Home Depot, removed the bottom of the DPS16, and fit it into the top of the cabinet. I also replaced both the hard drive and the internal fan with quieter models, and I placed them below the DPS inside the cabinet on soft surfaces to avoid mechanical noise coupling. The acoustic improvement is very considerable and now the unit is suitable for live recording of acoustic, nylon-string guitar, which is one of the quieter instruments commonly recorded. One more item, on high gain the internal DPS mic preamps are noisy so I'm using an external mixer for my preamps and only put line-level into the DPS.

All the goodies: my fan is a 80mm "Silencer" unit rated at 20 dB(A) from PC Power and Cooling . You can get an equivalent "Ultra-Quiet" fan from QuietPC . The new disk drive is the Seagate Barracuda 40 GB model ST340016A (single platter 7200 rpm, 20 dB). It is listed as Ultra ATA/100 but anyway it works as a direct replacement for the supplied ATA drive in the DPS16. It formatted OK (takes almost 2 hours) and works with no trouble. My microphones are the CAD M179 and Sound Room Oktava MC012 mics, and a Samson Mixpad 4 as a preamp. Certainly better gear exists but this is fine for my needs now.


Top view of DPS16 on cabinet: I used blue masking tape to seal off some of the edges so more of the cooling fan air passes near internal power supply (back rear of unit) on its way out of the cabinet. Rear view of cabinet: a U-shaped cut in the back allows access to rear connectors while the main console sits flush with the cabinet top. The red plastic trim pieces on the side have been removed so the top sits flush, and the resulting gaps taped off. I didn't say it was pretty. This cabinet is too tall for convenient use while sitting, although about right for operating standing up. I will probably eventually build a shorter cabinet, and put wheels on it also.


top view

back view

Inside the cabinet, the disk drive is just sitting on a cardboard box covered with a towel- clearly not a permanent installation. I have some metal mounting brackets on the side of the drive which are acting as heat sinks since I noticed without the fan on, the drive can get quite hot. With the fan, there is no noticible warmth at all and the extra heatsink area is probably not necessary. The 12V fan is connected by a "Y" power splitter cable to the disk drive power and sits in the corner pulling air up through a hole in the shelf from the bottom half of the cabinet (which is vented at bottom rear).

inside 1

inside 2

The fan is quiet if you hold it in your hand, but more noisy hard-mounted to the wooden shelf. I wrapped a length of bicycle inner-tube around the fan and glued it. It seems fairly stiff, but it very effectively reduces conducted noise. I also found the center body (motor) of the fan makes a slight rattle noise unless you put some force on it. I glued a steel weight to the back of the fan (blue cylinder in photo) which presses down on the fan while it is sitting on the shelf, and that removed all rattles.

fan bottom

fan top

fan installed

Q: Any ideas on how I could reduce the noise without having to take apart the unit? I'd be willing to have a carpenter custom build a cabinet.

A: The two noisy things are the fan and the hard drive. The fan is really tiny and there are probably no very quiet fans which are that small and also move enough air to keep the HDD and power supply cool. You can get quieter hard drives than the standard model, but they are not completely silent. You could remove the internal hard drive and just use an external SCSI hard drive which you put somewhere in a cabinet. You could build a cabinet around the entire DPS16 unit but that makes it difficult to access the controls.

Q: How can I get more information about the DPS16 ?

A: There is an active mailing list for users of the Akai DPS12 and DPS16 products: groups.yahoo.com/group/akaidps12. The Akai professional audio products website is www.akaipro.com.

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