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Old 17th September 2009, 11:54   #16
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Try the same with some real powerful mono amp as box looks ok with that size.
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Old 28th April 2010, 15:47   #17
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I was thinking of making a new woofer box...infact 2 boxes. Just wanted to know if its gonna be worth the effort.

Below is the dimensions of the box that i am currently using


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Since i am tight on space DD site recommends "High Efficiency Compact size" in the image displayed below.
http://img404.imageshack.us/img404/579/ddbox.jpg

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Question. How much of a difference would i see, if i make two boxes suggested by DD site and play woofers separately? Not changing the amp.

By looking at the dimensions as suggested by the DD site, I think i have space to squeez two boxes in the boot.

Is it worth the effort of changing the box?

amp would be the DDM3 amp that i am using currently playing 2700watts rms @ 1 ohms.

Last edited by Technocrat : 28th April 2010 at 16:04.
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Old 28th April 2010, 15:56   #18
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Here's my question.

Why are you looking at a change? What are you lacking that you wish to improve?
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Old 28th April 2010, 19:10   #19
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Quote:
Originally Posted by Sam Kapasi View Post
Here's my question.

Why are you looking at a change? What are you lacking that you wish to improve?


My answer...if i knew what change will happen, I would have never asked the question

Currently the system performs and pounds bad...just wanted to know, if a redesign of the box will play the woofers even lower OR louder OR cleaner. Moreover, if i am correct bigger the box = lower the stress on the amp.
End of the day, if nothing else happens atleast science behind box building will be discussed


I have seen people using DD and other good brands play a lot with box design. So was just trying to milk more out of the investement.

Last edited by amit_sound : 28th April 2010 at 19:18.
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Old 28th April 2010, 19:38   #20
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There are differences in the internal volume of the box you are using and the one mentioned by DD, the one that you are using has 3.64 cu.ft. for both the subs. Where as if you going by DD enclosure, each sub gets about 2.23 cu.ft. i.e. 4.46cu.ft. for both the subs.
Which means the DD enclosure will take up more space and would result in slight lower response. I would say stick to the present enclosure if you are happy with the response if not get the new enclosure.
Also like to add the response will be better if the construction of the enclosure if good and is well damped. With the size you are using add bracing and some acoustical foam will give out bit better response.
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Old 28th April 2010, 22:34   #21
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Amit what is the investment in making a new box. I think it is not so big. I have invested a lot in the same made nearly 15 boxes for my swift . So experimenting !!!!

With every thing the same but bigger enclosure here from 4 cuft box to 10 cuft box there was a gain from 141db to 145 db. Hope you get the point.

In a ported box you need to control lots of parameters. The port area, port length, internal volume, port volume. Sometimes it very confusing. Also on the DD site the enclosure are tuned close to 40hz I like to tune my enclosure to 25-30 hz. Presently using a 4 cuft box for a single 15 inch sub with tuning at 28 hz. SQ is brilliant, Blends with the front stage completely and does no go boomy or anything. And goes loud also..!!!!
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Old 28th April 2010, 23:02   #22
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Quote:
Originally Posted by low_bass_makker View Post
Amit what is the investment in making a new box. I think it is not so big. I have invested a lot in the same made nearly 15 boxes for my swift . So experimenting !!!!
Abey! milking investment is for woofers!! not the box. U got confused.

Quote:
Originally Posted by low_bass_makker View Post

In a ported box you need to control lots of parameters. The port area, port length, internal volume, port volume. Sometimes it very confusing. Also on the DD site the enclosure are tuned close to 40hz I like to tune my enclosure to 25-30 hz. Presently using a 4 cuft box for a single 15 inch sub with tuning at 28 hz. SQ is brilliant, Blends with the front stage completely and does no go boomy or anything. And goes loud also..!!!!
Agree it very confusing...so wanting gyaan from gurus.

Quote:
Originally Posted by Invinsible View Post
Also like to add the response will be better if the construction of the enclosure if good and is well damped. With the size you are using add bracing and some acoustical foam will give out bit better response.
Have taken care for the current setup. Its well braced and had foam inside.

If i plan for a bigger box, will make sure it repeated there.

Last edited by Technocrat : 30th April 2010 at 19:41.
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Old 28th April 2010, 23:40   #23
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if a box is tuned higher , say 40hz , it will roll off frequencies below 40hz . giving poor low end extension. so tuning a 30hz is safe bet for almost all music except test tones.

a bigger box will help anyday , presenting less stress on amplifier but again in order to get some lower notes, the higher octaves over 60hz will suffer big time. giving a dip at higher frequencies responce curve making music less fun and excited.

use some polfill instead to get some more lower octaves and keeping the music energy alive . both box looks fine but if you want to get some more output , go with a bigger box
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Old 29th April 2010, 00:02   #24
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Quote:
Originally Posted by amangujral06 View Post
use some polfill instead
Sry, did not get what polfill means
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Old 29th April 2010, 00:06   #25
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Quote:
Originally Posted by amit_sound View Post
I was thinking of making a new woofer box...infact 2 boxes.
Question. How much of a difference would i see, if i make two boxes suggested by DD site and play woofers separately?
What do you find wrong with the current box. Is the bass too dry, too boomy, not tight enough?

Download some software like Boxplot and see how the box change will affect the woofer's output.
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Old 29th April 2010, 00:13   #26
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Nothing wrong with the setup. Just curious to know what might happen when the box size is increased.

Anyone willing to help with the software navin mentioned?

Last edited by amit_sound : 29th April 2010 at 00:16.
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Old 29th April 2010, 11:30   #27
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Quote:
Originally Posted by amit_sound View Post
Nothing wrong with the setup. Just curious to know what might happen when the box size is increased.
Since the box (3.5 cu. ft) you are using a slightly smaller than that recomended by DD (I assume the recommended box size assumes a Qtc or 0.7) the response you will be getting will have a slight peak (2db or so) in the bass and will roll off faster than if the same woofers were put in a box of say 4.5 cu. ft.

In the recomened box the woofers will play a bit louder in the low abss, go a bit lower but you will loose some midbass sensitivity.
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Old 29th April 2010, 12:35   #28
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In addition to what Navinji has mentioned just to add the smaller enclosure than the recommended you are using will give slight better SQ and some better low end response provided you use the port tuned at 30hz or so.
At the lower end of the ported enclosure's response, the phase will be dramatically different than the upper end (i.e. 80 hz). Now granted, the frequencies that this is starting to happen at, and be very noticeable, are frequencies the sealed enclosure is fighting to reproduce, even with EQ. Now this is a generality, and in essence only valid when all other variables are the same. Phasing can get screwed up by all sorts of other variables, and not surprisingly, many of them exist in a car.

So, what does a phase difference equate to. Well, when something is out of phase, that frequency becomes very prominent, or rather stands out. This is pretty common knowledge in the SPL community as it's a trick to get your subwoofer to appear a lot louder. It won't produce higher SPL numbers, but when sitting in the car, it will seem louder. To the SQ person, this can be a problem in that we like our sub's frequency response to blend better with the front stage.

So, what does a ported enclosure provide? Low end extension, and a generally flatter response down to it's low end. By going with a smaller box, tuned low, you can reduce your group delay, and phasing variations. This could account for the difference in "SQ" that you hear. However, you start to lose the low end extension the ported design affords you. It can still be better than a sealed enclosure, so it's an option in many cases. Extended bass shelfs in a car are pretty useless in my opinion for anything that would resemble an SQ installation.

All this being said, it comes down to what you want, and what you're willing to sacrifice. Nothing is perfect, and you just do the best you can, with a lot of trial and error. I've found mid sized ported enclosures, tuned low seem to be the best compromise.

If you look at the recommended enclosure by DD, will give out better smoother low end and will sound better with xover limited to 63 or 80hz.
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Old 29th April 2010, 13:15   #29
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Quote:
Originally Posted by Invinsible View Post
In addition to what Navinji has mentioned just to add the smaller enclosure than the recommended you are using will give slight better SQ and some better low end response provided you use the port tuned at 30hz or so.
OMG. I totlaly forgot he was talking about a proted box. I was assuming sealed.

For a ported box I'd highly recommend going to a recomended size or even a little bigger. I have had great results with EBS (EXtended Bass Shelf) alignments for ported woofers (Focal 8N515, Peerless 831727, and JBL 2245) oh yes the JBL 2245 in an EBS box meant a box bigger than most coffins.
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Old 29th April 2010, 14:06   #30
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this is th kind of gyaan was looking for.

I have taken the measurements of the boot and two boxes recommended by the site do fit into it. Will take the measurements again to see if the boxes can be made bigger. I measured by having 1" MDF in mind but DD site suggest 0.75" mdf. If you notice the box, the port is not facing the woofer.

The way i plan to fit in the woofers is where both the ports facing towards the boot lid and both woofers facing each other.

Currently i have the port and woofers facing the boot lid.

Had read sometime ago on the forum about woofers facing vs SPL. I assume i should be fine as again the port of the boxes face the lid.

Will post the measurements today in the evening.
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