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odysseybmx414 10th March 2010 08:50 PM

Thoughts?
 
1 Attachment(s)
Kind of new to this. Here is a design I have made. It was created with WinISD Beta (free version).

This will be going in the trunk of my 2000 chrysler concorde, powered by around 200 watts of power give or take. I don't want to win any competitions, I don't want boomy loud bass, I don't want to show off to people as i drive by. What I do want is smooth, low response, with authority, and sound quality.

I would like the box to stay as small as it is, 1 ft3. I do need to use my trunk...

The driver is this one: Parts-Express.com:Tang Band WT-1427G 10" Neo Subwoofer | WT-1427G subwoofer 10" subwoofer low profile thin mount neodynium subwoofer tangband tb speakers

I will use a 2.75" Internal Diameter, 17" Length port, giving tuning of 28Hz. This gives me -3db @ 29Hz. Probably PVC piping. The box will have an inside height of 19", so it will have 2+ inches of space from the other wall of the box, depending on the thickness of the mdf i choose to use.

Just want to hear somebodies thoughts on this before I go out and spend ~200 bucks on putting the sub together.

I appreciate the thought.

fouchagalaga 12th March 2010 08:04 PM

I'm no expert, but I now know that Ported enclosures can be tricky.. a 2,75'' seems pretty small to me. You may have a lot of port noise. A port should be atleast half the area of the cone area to work. I can't say it won't work well, but maybe someone with more knowledge then me should look into this?

odysseybmx414 12th March 2010 08:34 PM

Winisd says "vent mach" is 0.15, and it is green, which (i think) means it is OK. If i go even a tad bit smaller than 2.75, it turns red, which means (i think) that the port velocity will be too high.

I would make it wider, but then my port will be longer, and more difficult to fit inside the box. I would have the port outside of the box, no problem, but I want it to be compact, as to save trunk space.

I will not be listening to this at maximum power regularly, mostly at volume enough to talk to others inside the car, while listening to music. Or if i am alone, it may be loud, but nowhere near maximum power.

I will have a subsonic filter on this to keep the sub from producing anything too low potentially damaging it.

Overall, it seems this is a rather inexpensive way to have a sub in the car, and one that is actually smooth in response, and not "boomy". I do want the potential to be able to crank this thing up and get some decibels, but it is not my goal to be one of those guys driving down the road with my car falling apart.

So, if you think the port may chuff at very high amounts of power, but be just fine with normal "loud" listening levels, then I think i will commit to this build. I guess if needed, i could always make the port bigger later on, right?

edit: BTW, thanks for the response.

fouchagalaga 12th March 2010 11:33 PM

As i said, I'm no expert. When building my own ported sub, I had a port match of 0,08 but yet my ports sounded AWFUL even at 80 dB. I initially thought it would work well, but now it has become complicated to put better suited ports. I'm just saying that it MIGHT be an issue and maybe something to consider. Someone better than me should be able to say if this is an issue. (HINT TO OTHER FORUM MEMBERS...)

Cokewithlime 13th March 2010 03:52 AM

Honestly for your requirements and a 1ft^3 enclosure I would recommend that you look at the Tang Band W8Q-1071F 8"x12" Subwoofer and do a sealed enclosure. The 8x12 will outperform the 10" in having more xmax and output - it is also rated at twice the power capability of the 10" - and with cabin gain inside the car this will give you more than enough LF to rattle anything that is loose with the car - if you want to turn it up ;)

Overall the two subs are about the same price but the 8x12 in a sealed box will be a simpler build for you and give you, I think, results that you will be really happy with.

odysseybmx414 13th March 2010 05:09 PM

Hi, cokewithlime, thank you for your response. I have modeled that driver, and with neither a ported, or a sealed enclosure, will I be able to get lows extended to the length I can with the other driver, at 1 ft^3. I understand that with cabin gain it will help make up for it, but will that not also produce a peak in the upper sub frequencies, that will not be equal to the response of the lower ones?

Also, very high spl and loud bass is not necessarily what I am looking for here. Mainly what I want is smooth response and the capability of low frequencies. Of course I want it to be able to be loud also, but more want to focus on low frequency response and smooth.

Forgive me if I misunderstood your post or I am missing something here.

It should be noted that I like a large variety of music, and some of it does have content that could be well below 30Hz.

event horizon 13th March 2010 06:02 PM

odysseybmx414, i suggest you download a copy of WinISD pro.

If you do that you'll really be able to get a decent idea of how that 2.75" port will perform. Instead of just getting a mach number of say 0.15 (you do realise that means the port velocity will be 0.15 x speed of sound :D or 49.5m second/ 162.3 ft per second) you'll be able to see the velocity of the port air at different frequencies & powers. You'll also see how much power the driver can handle (excursion or power limited) at any frequency. That's only the half of it while i think about it...

Take it from me, the Pro version is vastly superior :) They are both free & i have both, i can't remember the last time i used the earlier version though.

Cokewithlime 13th March 2010 06:44 PM

Quote:

Originally Posted by odysseybmx414 (Post 2117842)
Hi, cokewithlime, thank you for your response. I have modeled that driver, and with neither a ported, or a sealed enclosure, will I be able to get lows extended to the length I can with the other driver, at 1 ft^3. I understand that with cabin gain it will help make up for it, but will that not also produce a peak in the upper sub frequencies, that will not be equal to the response of the lower ones?

Also, very high spl and loud bass is not necessarily what I am looking for here. Mainly what I want is smooth response and the capability of low frequencies. Of course I want it to be able to be loud also, but more want to focus on low frequency response and smooth.

Forgive me if I misunderstood your post or I am missing something here.

It should be noted that I like a large variety of music, and some of it does have content that could be well below 30Hz.

In a vehicle you are really unable to perceive anything less than 30Hz - in fact the gut moving and chest thumping in a car that you associate with LF happens between 40Hz to 80Hz.

I modeled both drivers in WinISD PRO and honestly, the 8x12 in a 1ft^3 sealed enclosure will provide you a much smoother LF extension well suited to a sub in your car than the neo10" in a similar size ported enclosure. If you where building a sub for your home environment I would probably say the exact opposite. Besides looking at graphs you also have to have some real would experience into how these designs actually sound and work in the environment they are intended for.

odysseybmx414 13th March 2010 10:05 PM

well thanks coke, I will take your word for it. This will not be built for a while, at least for a couple months, but I want to get the plans down.

Hell, 8x12 will be easier for me to cut than a circle anyway.

Only other thing I have to figure out is how much I have to compensate for internal box volume in terms of bracing.

Thanks guys!

Cokewithlime 13th March 2010 10:20 PM

Just oversize the enclosure volume by about 5%, that will account for any and all internal bracing you put in.


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