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Digital Designs 512a


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#1 ~Samuel~

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Posted 10 December 2009 - 05:39 PM

Last month DD Direct offered MEA members 25% discounts on selected products inculuding the entry level 510a and 512a subwoofers. Considering the already discounted price offered by DD Direct i decided to purchase one to have a play with or keep as a present for someone. Following the death of my IXL18 i decided to have a play around with the DD512a to see what sort of performance could be obtained from a sub $200 dollar 12 inch subwoofer. To begin with i was highly optimistic that the DD512a would be able to produce to sound that i would be happy with. But you never know until you try...

The first place to start is with the unboxing of the sub, packaging is very solid, DD are renowned for there good packaging. Although not very environmentally friendly the sub was secured in a polystyrene foam mould that stoped the sub from moving and protected the motor from damage.

This photo highlights the high foam surround.
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Stamped steel basket with cooling slots around the top of the motor, you can view the 2inch coil :)
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Glue job on the dust cap was reasonably neat as it was on the surround and spider, once again better than i had expected.
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This photo highlights the motor structure next to the motor from a Jaycar Venom 15, if there was anything to pick on it would be that the motor has some chips and the stacks do not line up exactly, this would normally have been covered by the rubber boot that the drivers comes with and does not effect performance in anyway...
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First impressions when comparing this sub against other $200 commercial subs are that this is a no frills package that is designed with performance over looks. Very simply basket with a double stacked motor structure. High roll surround is a bonus as are the direct leads and more importantly the tinsel leads in the spiders. I was very impressed when i first viewed the subwoofer :good:

The next step in my quest for reasonable bass from the DD512a was an enclosure. I decided to run with the recommended airspace of 2.5 cubes. I did however decided to use slightly less port area then recomemnded with a single 154mm round port. The box is single layer 18mm MDF with the exception of the baffle which is triple layer. As you can imagine the box is fairly solid. I started with a fairly high tuning at 42Hz :)

Box with the driver in a trial fit, i used a Jaycar speaker terminal on the back of the box with 8 gauge power cable from the termianl to the direct leads on the sub, the box looks larger than it really is
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I also decided that it would be a great idea to make some ports that i could play around changing the tuning and listening to what impact that had on the overall performance. In addition to the origional port thats tuned at 42Hz i made some screw on lengths to lower the tuning to 35Hz and also lower at 32Hz :good:

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In the next post i will look at Install and the eqipment used in the review :D

Edited by SPL Samuel, 10 December 2009 - 09:45 PM.

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#2 ~Samuel~

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Posted 10 December 2009 - 07:11 PM

The car is my 1997 Ford Laser, small sedan with folding rear seats. I have listened extensively with the seats both folded down and up. Power comes from a Hertz HP1KD which is rated at 3200 watts at 1Ohm and 1500watts at 4Ohm.

A fairly serious SQL amplifier.
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It is nice to be able to put a subwoofer through its paces without having to worry about clipped power, although not many people looking at purchasing the $175 DD512a will have this kind of power I decided it was still worth while using it for the review, at a later date I will have a listen to the sub through a much smaller Jaycar mono block rated at 300 watts at 4Ohm which perfectly matches DD’s power rating for the driver, it will be interesting to see how it performs with less power.

Having clamped a burp at 35Hz I know for a fact that the driver has been seeing roughly 850 watts, far above the drivers rated power handling.
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To begin with I started with the driver facing forward with the port firing to the passengers side of the car, the setup stayed like this until I felt like the woofer had broken in enough to begin having a play with positioning.
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After experimenting with driver forward, up and back i decided that the cleanest sounding position was subwoofer firing into the car with the port loading to the driver’s side. Firing back into a rear corner the sound was a little deeper and the sub seemed to perform better on chopped and screwed songs but with less clarity on other music genres.
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This is a better photo of the ports that are changeable, this photo shows the 35Hz port.
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Edited by SPL Samuel, 10 December 2009 - 07:41 PM.

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#3 ~Samuel~

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Posted 10 December 2009 - 07:22 PM

I listen to everything, all different genres from Trance to Latin Jazz and everything in between. I am also a total bass head from time to time listening to albums such as Bass From the Krypt and various other Bass CD's. In the car i like to have the gains set on the amplifier so that when the sub level on the head unit is on 0 the bass is blended with the fronts, not to over bearing or in your face, in fact i like to have it set so that sometimes you have to turn your head to check that the sub is even on. However then when the sub level on the head unit is increased to +15 is like being in front of the bass bins at a large concert :D

To begin with i was unsure if the DD512a would be able to satisfy either high output or clarity for softer music genres.

The first thing that i notice going from the Mach5 IXL 18 to the DD512a was the response of the driver above 60Hz. To begin with i had the crossover set rather high at 80Hz because i found that the IXL rolled off above 60Hz. First listening session and the DD512a just about ripped my ears off on the mid bass. :shok: At first i was horrified by the sound but after having a play with the gains and the crossover i decided that people running cheaper fronts like my Jaycar 6inch Kevlar splits would be able to run the DD512a higher up to reinforce the mid bass slightly. I ended up with a final crossover of 65Hz.

I started with the 42Hz box for a week or so until the driver had loosened up enough to play around with different tunings. Even in the 42Hz box the DD512a seemed to handle power very well bellow tuning. I got quite a surprise when i played some chopped and screwed, despite the high tuning there was still very reasonable output down into the low thirties. Kick drum sounded very clean with a certain snap that i had not heard in a car before, the IXL18 was certainly never able to reproduce kick drum like the DD512a can. Next was the 35Hz port, the bottom end extended just that little bit extra that added realism to the low B on bass guitar that was noticeable. There was a very noticeable increase in output when playing Bass CD's and other electronic music. Finally i decided to try a 32Hz port only to find that i did not gain very much, however power handling did suffer considerably. Both the 42 and 35Hz tune handled power very well but the driver really struggled with the 32Hz tune, this was only a problem at very high levels but it was an issue that i noticed when going from the 35Hz port to the 32Hz port. I think the driver sounded best with a 35Hz tune which is where most people will end up tuning the driver anyway.

While i am no expert on SQ i found that the sub performed very well, everything from fast double kick drum to low bass guitar note was reproduced well enough, in fact my splits were the limiting factor in reviewing this subwoofer. Quite a few different people have sat in the car and listened to various music styles and most have commented on how clean the bass sounds. I was expecting the driver to sound boomy and sloppy at times but it did not. It’s important for me to say that my experience and interests is with SQL and SPL subwoofers not SQ, to my ears however i was very satisfied with the response from the driver on different music styles. There was not one moment where i though 'that just did not sound right' in comparison with the studio monitors in my room.

For a $200 driver the output is quite incredible. To be fair to the competition i have only heard similar priced subs in cheapish prefab boxes but the output from the DD512a has suppressed many people. I have had a lot of people in the car to give me their opinions and most are very shocked first by the output and then by the asking price of $175. For someone looking to get loud with a very strict budget i really do not think you can do better for $200. It will be interesting to get some Term-Lab results for the driver but it is certainly almost as loud to the ear as my previous 18. There is very visible flex from the front windscreen and rear doors not to mention the boot which flexes a little too much. It really did take me by surprise. The common theme from people who sit in the car to have a listen is real surprise by how much output you can obtain from a $175 woofer. Just as impressive is the fact that is stays reasonably clean even at high volume levels.

This sub is one tough little cookie, Digital Designs rates the power as 300 watts RMS, i have been running it on an amplifier rated at 1500 watts RMS without any real problems. From time to time the driver has gotten smelly but after backing of the volume for a few minutes everything is fine. Even in the 42Hz box i ran the subsonic filter at 30Hz without any problems, sub would not bottom, only problem is when pushed hard it starts to smell. In the end i did damage the sub, with the 32Hz port and way too much power i bottomed the coil hard causing some damage :( However this is in no way a poor reflection on the sub, infact the driver managed to take far more than rated power for an extended period of time without any issue. If you stay around rated power i think you would have to do something very special to damage the driver.

It is really hard to fault this driver for the price, sure there are louder subs and much better sounding subs but for $175 i doubt you will be able to get a better SQL subwoofer. If your looking for a subwoofer to add depth to your car and you are on a limited budget the DD512a is a great buy :good:

I guess the really important thing to mention is the amount of FUN i have had with this sub, for what it cost i have had many hours of enjoyment cursing with mates or playing around with different ports.

This post needs some pictures, there is too much writing :P
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Ok sealed listening time :)

A few members have asked about how the DD512a sounds sealed so i decided to have a listen and go from there. Big Val was kind enough to lend a prefab sealed box that is common of what you find in installs with subs in the lower price range. It is a thin walled 1 cubed box that can be purchased from Jaycar etc. The sound was by no means poor, very punchy with good defenition on the higher notes, sounded really good on hard dance and kickdrum. However the bottom end was very lacking. It was fairly obvious that the 1 cube box was too small for the DD512a, even with much more than rated power the subs travel was very limited and would become quite distorted far before it reached its mechanical limits. So next i decided to jump to another extreme and try the DD512a in 2.5 cubes sealed. This was a large improvement over the 1 cube box. The low end was much better as was the output, even with five times rated power the driver seemed to handle power very well. I was even able to run without a subsonic filter in the 2.5 cube box without mechanical problems. I think this sub will perform better with a larger than normal enclosure, i would be looking at 1.5 cubes minimum with some polyfill. It is important for me to note that no matter how hard i have tried with different boxes and setting i cannot get the DD512a to hit really low notes. For 99% of music it is not a problem but on some songs you can notice that the low lows (like bellow 35Hz) are not as full sounding as they should be. Big Val and i noticed this when moving from his car with the JL audio W3 (a $400 subwoofer). In response to the questions. The DD512a can be used sealed and will sound good when doing so. The trade off is a significant loss in output. For my listening tastes i would need two DD512a's sealed to get enough output. In a small hatch a single DD512a would provide solid botton end reinforcement and be more than loud enough :good:

Edited by SPL Samuel, 16 December 2009 - 01:58 PM.

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#4 ~Samuel~

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Posted 10 December 2009 - 07:35 PM

As part of the entry level SPL 12 challenge organised by Sorin i will be getting some TL scores for everyone, very interested to see how the DD512a scores on the meter :)

Here they are :good: I believe there is more to be had with some changes and testing thats for sure

Here are the scores that people have been wanting :D They are also up in the Entry Level woofer challenge thread in the SPL section

A photo of the setup
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48Hz
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52Hz
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50Hz
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Up next will be a 25mm MDF box with a proper flared at both ends port and slightly higher tuning :yahoo:

Edited by SPL Samuel, 19 December 2009 - 07:22 PM.

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#5 bobo333

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Posted 10 December 2009 - 10:15 PM

very thorough review, and being one of the people lucky enough to hear this sub in action with a couple of different ports i can agree completly, it is easily the loudest and cleanest single budget 12" ive come across and would be perfect for anyone from the average "doof doof" driver to someone with more refined music tastes looking for some bottom end reinforcement :)

keen to see how it goes for numbers soon :)

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#6 Big_Valven

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Posted 11 December 2009 - 10:13 AM

I'll add my opinion having heard it at 45Hz... At this tuning it was remarkably fast and articulate for natural music, as Sam has already mentioned it suffered a little with some electronic music but only at very high levels.
For a cheap woofer it actually sounded very... non-particular. Most cheapies have a boxy, boomy, reverbarated, sound or on the flipside some are overly deep but very uncontrolled and laggy (a variable partially dictated by the box as well, I know) but this one performed admirably smoothly. If you ARE serious about your music (and if you know of DD you probably are,) and you set this up right, it is a bargain basement driver for daily listening and even novice SPL use that will not disappoint.

The caveat I'd apply is that it was "fed with a silver spoon" from day one, so to speak - big ported box and stacks of very clean power. It says a lot for power handling and durability, but at this end of the market so many people end up slapping it in a cubic foot of prefab 12mm box and powering it off the bridged channels on a 4ch amplifier, or a tiny monoblock... I guess it represents those who don't really get into audio but just want bass, so don't understand a big enclosure when you can get a smaller one and keep boot space... and to that end I'd be very curious to hear it from rated power in less than 2 Cu Ft, ported.

The only other remark I'd have is the foam roll surround, because I have a pathological hatred of them, and I've seen cheaper woofers with rubber surrounds, so they could have improved on that, but many people simply won't notice.

:D

#7 ~Samuel~

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Posted 11 December 2009 - 10:53 AM

Thanks for adding your opinions guys, much appreciated :good:

RAD has asked for me to have alisten with a 1 cube sealed box so i will get onto that in the next week, i will also spend some time listening with my Jaycar mono which should give a better indication of how most users will apply the DD512a. I might 'borrow' a Jaycar prefab thats roughly 1 cube for a week and wire up the Jaycar mono so you can have a listen to it like that Big Val :)

I have a few 12 inch sub $200 drivers to do some compairisons with in the upcoming month so stay tuned MEA

Who can feel a big sub $200 12 inch shootout coming?
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#8 chinabone2000

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Posted 11 December 2009 - 02:32 PM

wouldnt mind finding out how they would go in a 2 cuft prted box

#9 ~Samuel~

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Posted 11 December 2009 - 03:05 PM

Hey man your in SA, im happy to put a brick in the box so its 2 cubes and you can have a listen :good:

Just shoot me a PM and we can meet somewhere :)

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#10 Big_Valven

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Posted 11 December 2009 - 03:34 PM

Sam, I'll do you one better and give you a cubic foot prefab box I have in my backyard for testing purposes :D

#11 ~Samuel~

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Posted 11 December 2009 - 03:39 PM

Awesome :good:

Ill shoot you a text to arange a time to pick it up, great stuff :)

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#12 beastvs

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Posted 15 December 2009 - 10:24 PM

Whats the different between the 512 and the 512a ?
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#13 El-Camino

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Posted 16 December 2009 - 07:14 AM

Do you think a DDM1a mono block (1200wrms) is enough to power 2x DD 512a with 4 cubs?
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#14 ~Samuel~

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Posted 16 December 2009 - 08:21 AM

El-Camino, on Dec 16 2009, 07:44 AM, said:

Do you think a DDM1a mono block (1200wrms) is enough to power 2x DD 512a with 4 cubs?

The final load would be 2ohms meaning roughly 600/700 watts which is just about right :good:

Are you thinking sealed or ported? Two in 4 cubes ported at 35Hz would hammer hard :D Then again in 4 cubes sealed they would sound good too, if you want any help designing a box shoot me a PM

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#15 ~Samuel~

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Posted 16 December 2009 - 08:24 AM

beastvs, on Dec 15 2009, 10:54 PM, said:

Whats the different between the 512 and the 512a ?

Id probably shoot an Email to DDdirect, i think in the states they have the DD512b now, probably slightly different motor and/or soft parts too

I will update the review later this week with some great internal photos :P

Having cut one open to have a look i am very impressed, dual spiders, a very solid former etc, trust me i think you will all be supprised at the coil photos too :)

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