Pair of TD12H as subwoofers

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    catalyx on #1231

    I’m building a pure SQ system so am looking for super low distortion and fast accurate dynamics in a pair of subwoofers. The TD12H drivers are obviously designed to perform into the midbass/low midrange frequencies but their specs are so nice I’m curious if they would do well as dedicated subs low-passed at 80Hz. I would apply a subsonic filter to cut signal below their Fs.

    By using two I should have plenty of displacement for my purposes so is there any other reason this wouldn’t work?

    taloyd on #10931

    You’re talking about using >$500 of speakers for <50 Hz. of bandwidth (Fs to 80 Hz.) when a variety of other speakers would be more practical. The biggest problem I see is that they'd require a larger box than a single dedicated woofer. Anything crossed over that low doesn't need to be the most fantastic driver in the world (ie: the AE drivers). To get an accurate system – the system design is key. Getting the crossover right, and picking the most practical, applicable drivers. Just my $0.02.


    catalyx on #10932

    Most of the car specific subs I’m looking at are $250-$500 each so the TD12H’s price isn’t an issue. I would use a IB12AU but have a hatchback so infinite baffle is out of the question.

    The TD12H has a Fs of 26Hz so I could low pass around 85Hz to get closer to 60Hz of bandwidth. Though maybe it would be better to use the TD15H for its Fs of 21Hz.

    I know the box will be need to be quite big to tune that low but since it won’t be in my car all the time I don’t mind completely filling the cargo area.

    Anyone else have thoughts on how practical this would be?

    stryke on #10933

    I have used many TD12H’s in vehicles over the years. They are quite efficient and can get loud in small enclosure volumes. You don’t have to worry so much about the FS of the driver, just the Fb of the enclosure. You want to cut below the Fb of the enclosure to prevent over excursion.

    In reality if this is an SQ system, a pair of TD12H could definitely be overkill. A single TD12H in a 2cubic foot enclosure tuned to 30hz can get very loud. You can input 1000W without running into the excursion limits of the driver. This will give about 122dB at 100hz without any cabin gain. If your front stage cannot equal this, then you probably don’t need to go with more than the single TD12H. At 30hz you will be capable of about 115dB, again before cabin gain is factored in. Once you add 20-30dB of gain at 30hz, the system can get quite loud. Also, tuning that low starts to get difficult. I have often done a system that looked like 3 12’s right behind a seat in a wide cabinet using one active driver and 2 passive radiators to get the tuning. This also allows you to tune very low, 20hz or so.

    The first thing to do is to evaluate the cabin gain in the vehicle though to determine how much output you need at which frequencies. Then you can plan around it.

    This shows the output capability of a single TD12H though. Keep in mind the TD12H is nearly 10dB more efficient than most car audio 12″ woofers.

    catalyx on #10934

    Thank you for the informative reply. I should give more details for the planned build to better discuss the possibilities.

    My car is a VW GTI hatchback that is going to have a false floor amp rack installed in the cargo area. There will also be a 10″ subwoofer mounted in a sealed enclosure within the center of the rack. It will be receiving 350W RMS which should blend with the front speakers very well for a SQ system.

    I’m opting for the under floor placement so I can have full use of the back when I take trips or need to move things. However, most of the time the cargo area is empty so I’d like the option to have more bass with a box. I’m not a decibel junkie at all but do like to play stereos loud and the front stage is designed to handle a lot of power so will be able to match bigger subs.

    One limitation I have is the amp powering the sub(s) is 120Wx4 which bridges into 350Wx2. The base system will be using it as a three channel to power rear midbasses and the 10″ sub. The reason I asked about two TD12H’s is I could significantly increase the low end wattage and displacement by disconnecting the rears to send 350W to each subwoofer.

    However, lately I’ve been thinking a single 15″ would be a better choice to reduce cost, save space and avoid the hassle of swaping as many speaker cables. One of the main reasons I’m interested in AE speakers is their high efficiency so perhaps the one sub would produce enough with my limited watts.

    How well do you think a TD15H would perform with an 18″ passive radiator and 350W?

    catalyx on #10935

    For anyone interested, I answered my own question in the above post and decided on the TD15H and 18″ passive radiator.

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