the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
icon

designing w/winisd need advice


Post ReplyPost New Topic
< Prev Topic Next Topic >
dollarlongnecks 
Member - Posts: 9
Member spacespace
Joined: June 03, 2003
Posted: May 02, 2007 at 10:20 PM / IP Logged  

Hey Guys, I need some expert advice...

I ordered a new Kicker Solo-Baric L5 (square) 10" and I'm playing with WinISD to design the box. I've built several boxes in the past, but never with a software tool. After entering all the T/S info and looking at several different cofigurations, I'm wondering if I'm on the right track and seeing my results for what they are. I'll give you a little info about what I want, then show you what I'm looking at. I'm hoping that some of you that use this software often can give me your opinions or recommendations...

This setup will be for my Nissas Xterra, with a box in the back, facing the back of the truck. I currently have a solo-baric (round) 8" in a small sealed enclosure (about 1 ft^3), and it just doesn't sound right (and might have a bad vc)... The 4 ohm DVC are run parallel, and are being pushed with a JBL BP300.1 mono amp rated at 300 W RMS @ 2 ohm. I bought the 10" because I felt I needed just a little more volume range. I listen to just about everything BUT country, and am looking for a good sub that will give me good, balanced low end, but not necessarily win me any SPL contests. I'm looking for good, not loud or "boomy".

I have set up 4 projects and have been playing around and comparing them. Below are download links to the projects and the driver file if you want to play along, and below that is the Transfer Function Magnitude graph. The colors for the graph are listed with the projects below...

Custom Driver File for S10L5 D4 : <Here>

Project 1 (yellow) - Sealed box, settings left where WinISD put them : <Here>

Project 2 (green) - Vented box, settings left where WinISD put them : <Here>

Project 3 (lt blue) - Sealed box, setting at Mfg recommended max : <Here>

Project 4 (blue) - Vented box, this is the one I have played with and am thinking about building : <Here>

designing w/winisd need advice -- posted image.

designing w/winisd need advice -- posted image.

designing w/winisd need advice -- posted image.

designing w/winisd need advice -- posted image.

designing w/winisd need advice -- posted image.

Now, after looking at this, and playing around, and reading the forums, and searching the web, it seems to me that the BLUE line (project 4) looks pretty darn good... Am I on the right track here? I've played with the ports, and the size and the tuning freq, and as far as I've read, I'm looking for a response that is as flat as possible. This one seems really flat compared to the others...

So does this graph tell me "for sure" that this is the box to build? Are there things that may not be shown by the graph that I should be aware of? I'd like to get some feedback before I start building, so any and all info would be appreciated...

Thanks,

Ben

stevdart 
Platinum - Posts: 5,816
Platinum spaceThis member has made a donation to the12volt.com. Click here for more info.spaceThis member has been recognized as an authority in Mobile Audio and Video. Click here for more info.spaceThis member consistently provides reliable informationspace
Joined: January 24, 2004
Location: Pennsylvania, United States
Posted: May 02, 2007 at 11:59 PM / IP Logged  

Be sure to consult the cone excursion graph.  Read my WinISD topic stickied on this forum for details.  kfr01 has provided input about this in addition to what I wrote.  I suspect there may be the possibility of overexcursion with that alignment you show in blue.  The default vented green line response also is a likely candidate for overexcursion.  You have to consult that chart with all vented designs.

Otherwise, flat on a graph doesn't necessarily relate to flat in a car environment.  Because cabin gain fills in db in the lower octaves, the graph representation shown with the green line above should, in many environments, actually look closer to your blue line in a real-world scenario.  

Sealed subwoofers have an actual in-car low end output that defies the graph representation...due to cabin gain.  Don't make the mistake of building too much low end into your vented sub.  The addition of the cabin gain may create too much low end response.

Also check the vent length needed to achieve these reponses.  Drivers that model as "best suited for sealed enclosures" usually  need extraordinarily long vent lengths to achieve a halfway decent response.

Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
dollarlongnecks 
Member - Posts: 9
Member spacespace
Joined: June 03, 2003
Posted: May 04, 2007 at 12:11 AM / IP Logged  

Cool. Thanks for the reply... I did look at the cone excursion graph, and read a little about filters for that. Wasn't sure if that was common or not...and the port was pretty long, and I was looking at running it in a baffle type configuration...

I'm starting to wonder if I'm going about this the right way... I'm sure the Mfg recommendations are there for a reason.

Ben

sedate 
Silver - Posts: 1,173
Silver spacespace
Joined: July 03, 2004
Location: Colorado, United States
Posted: May 05, 2007 at 5:01 PM / IP Logged  

dollarlongnecks wrote:
I'm starting to wonder if I'm going about this the right way... I'm sure the Mfg recommendations are there for a reason.

No mfg's specs are there for people that are too stupid to do what you are doing.  Seriously you can do wayyy better with WinISD.  You will find constructing boxes with WinISD will give you incredibly good results.  I appauld you effort here and seriously encourage you to continue.  You are definately on the right track.

You can check the excursion against the xmax of your t/s parameters.. with 2 cubic feet for a single 10 you might have some issues.

dollarlongnecks wrote:
and am looking for a good sub that will give me good, balanced low end, but not necessarily win me any SPL contests. I'm looking for good, not loud or "boomy".

If I were you, I'd probably drop the box down to about 1.25 cubic feet and port it a bit lower, maybe about ~35hz.  You'd get the same curve without the risk of overexcursion...  and big huge boxes like that do sound boomy.

dollarlongnecks wrote:
So does this graph tell me "for sure" that this is the box to build? Are there things that may not be shown by the graph that I should be aware of? I'd like to get some feedback before I start building, so any and all info would be appreciated...

I think you need to keep your box size in line with the mfg's recommendations, but  you certainly do want a curve that looks as close to this as possible.

stevdart wrote:
Otherwise, flat on a graph doesn't necessarily relate to flat in a car environment. Sealed subwoofers have an actual in-car low end output that defies the graph representation...due to cabin gain.  Don't make the mistake of building too much low end into your vented sub.  The addition of the cabin gain may create too much low end response.

This is a technically correct statement but I disagree in terms of context... I've had the best results mimicking that flat curve as closely as possible..   I would encourage our OP to try the flattest curve first (the flattest curve he can get out of ~1.25 cubic feet that is), before worrying about something not particularly quantifiable, like bottom-end reinforcement.. with a single 10, the woofer is not going to get "too much" low end response anyway.

"I'm finished!" - Daniel Plainview
stevdart 
Platinum - Posts: 5,816
Platinum spaceThis member has made a donation to the12volt.com. Click here for more info.spaceThis member has been recognized as an authority in Mobile Audio and Video. Click here for more info.spaceThis member consistently provides reliable informationspace
Joined: January 24, 2004
Location: Pennsylvania, United States
Posted: May 05, 2007 at 6:00 PM / IP Logged  
(True dat, sedate.)  What sedate said there is good advice.
Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
dollarlongnecks 
Member - Posts: 9
Member spacespace
Joined: June 03, 2003
Posted: May 05, 2007 at 9:14 PM / IP Logged  

Well, I was about to call it quits and just build the largest mfg spec sealed box, but after reading your recommendations, I decided to play around with the size and freq and see what I could come up with. The grey line below is pretty much right to sedate's recommendations. It looks like it mimics the WinISD recommended sealed box quite well (the yellow line). Does this mean I can expect this design to act similar to a sealed enclosure?

designing w/winisd need advice -- posted image.

It looks like the excursion gets to about 5 mm past xmax at 20 Hz, and all of the ported designs I have played with seem to be very close to eachother. Is this a situation where I would need to consider a sub-sonic filter?

designing w/winisd need advice -- posted image.

This smaller size should alse be easier to deal with. I was getting worried that the box would take up half the back of my truck...

Thanks again for the help. Hopefully I'll be able to start putting this together next weekkend. BTW, since this box will be ported, do I really need to use 3/4 board? And can I use something like masonite to build the ports?

sedate 
Silver - Posts: 1,173
Silver spacespace
Joined: July 03, 2004
Location: Colorado, United States
Posted: May 05, 2007 at 11:21 PM / IP Logged  

dollarlongnecks wrote:
The grey line below is pretty much right to sedate's recommendations. It looks like it mimics the WinISD recommended sealed box quite well (the yellow line). Does this mean I can expect this design to act similar to a sealed enclosure?

Hmm.  Can't say I'm 100% thrilled with the grey line but it doesn't look terrible.

Okay... if you look at these lines (yellow and grey) acoustically.. they actually look quite different.  The grey line is running +/-3db from about 30-100hz... granted the curve looks a bit steep but in terms of subwoofers that really is a reasonably flat response.  Furthermore, in terms of subwoofer frequencies, while the yellow line does have a similar shape, the response drops off at a significantly higher frequency... down 6db from its peak frequency all the way up at 50hz.  These two curves/enclosures will not sound anything alike at all.

From this point, I'd try to bring up the 30hz intercept a up a db or two... try porting a bit lower than my original recommendations .. maybe ~28hz or so... I wouldn't go with a box larger than 1.25 cft. 

dollarlongnecks wrote:
Is this a situation where I would need to consider a sub-sonic filter?

Looking at those graphs, they all look like excursion jumps considerably around 30hz or so.  You might have a subsonic filter built into that amplifier (lots of sub-amps come with an undefeatable sub-sonic filter at 30hz or so).. you should check your owners manuel.  What is the xmax of that woofer you are using? 

dollarlongnecks wrote:
since this box will be ported, do I really need to use 3/4 board? And can I use something like masonite to build the ports

I always use 1/2" MDF and fiberglass resin to make my boxes.  I hate 3/4" MDF and I never use it... impossibly heavy.

I've heard the word masonite but I don't actually know what masonite is and I'm too lazy to look it up.  I always use PVC piping to construct my ports.  Slot port boxes are aggravatingly huge.  Try calculating your ports for 1" PVCx3 or x4 ports.  *REALLY* easy to build that way (bore the MDF out with a 1.25" paddle bit and shove the pipe in the hole, seal with silcone) and the ports stay nice and small and low volume.  You might want to sand around the edges of the pipe ... just round them off ever so slightly so they don't whistle.

"I'm finished!" - Daniel Plainview
dollarlongnecks 
Member - Posts: 9
Member spacespace
Joined: June 03, 2003
Posted: May 06, 2007 at 7:04 PM / IP Logged  

OK, so I went back and looked, and I actually had the freq at 37 Hz, so I've been playing with it, trying to flatten it out a bit. Because I'm still a little confused about how the graph should actually look, I did a range of frequencies and charted them all together. Below that graph is a close up of the 30 Hz intercept.

designing w/winisd need advice -- posted image.

designing w/winisd need advice -- posted image.

So, I would say that the 33-31Hz range looks to be the best of the group? They both sit at about 1dB higher then the original 37Hz graph...

I've checked with my amp manual and didn't see any reference to a sub-sonic filter, so it looks like I'll probably need to find one. The xmax of the speaker is 15.1mm, and nearly all the tuning freqs are getting up above that...

designing w/winisd need advice -- posted image.

And I'll have to continue to play with the ports. I'm still trying to figure out how I want this sucker to fit in the truck..

Again, thanks for the help. I'm hoping all this work is worth the effort...

sedate 
Silver - Posts: 1,173
Silver spacespace
Joined: July 03, 2004
Location: Colorado, United States
Posted: May 06, 2007 at 9:04 PM / IP Logged  

dollarlongnecks wrote:
Because I'm still a little confused about how the graph should actually look

Well... this is sort of an open question.  The beauty of WinISD is that it tells you how to make it look like anything.  Sometimes this can be very useful.  The general application.. yours.. is to create the 'flattest' curve from ~20 ~100hz.

Here, I would tell you to concentrate on ~30 ~100hz.  I never worry about sub30hz performance...  not much music outside of electronically produced hip-hop and trance really utilizes frequencies this low and trying to shoot for good response that low without a very large diaphram is, unless you are living in a Bose commericial, *very* hard to do.  You are running a 10, the lowest range you should aim for is ~30hz.

dollarlongnecks wrote:
so I've been playing with it, trying to flatten it out a bit.

For reference .. *my* bar for considering a subwoofer curve 'flat' is 30-100hz @ +/-3db.

I would consider all of these curves, except the yellow line, 'flat.'

I like the '33hz' line the most, but I think if you actually built all these boxes you find they'd sound all quite similar.

dollarlongnecks wrote:
so it looks like I'll probably need to find one. The xmax of the speaker is 15.1mm, and nearly all the tuning freqs are getting up above that...

Hmm.   Notice that the vented enclosures you modeled began to get that jump in excursion right @ the tuning frequency.. the woofer will behave as tho it is enclosed right up until the tuning frequency, where there is a fairly large falloff in the woofer's ability to control itself.  This reinforces other reasons that I think extreamly low tuning frequencies seem to produce the best results.  If you ported right at 33hz, you'd still only have 5hz or so where overexcursion would be a risk.... and even then only at very high power levels.  You'd have to be playing a ~20hz tone at full-tilt boogie .. this is less likely than you might think.  I mean.. don't stick a tone CD in your car and try it obviously, but in terms of ... listening to music... I think you'll be fine.

dollarlongnecks wrote:
And I'll have to continue to play with the ports. I'm still trying to figure out how I want this sucker to fit in the truck..

I told you how to fit the port length in my other post above. Get 1" PVC pipe from Home Depot.  It costs something like $3 for 8 feet.  With a 1.25cft box, three 4" sections of pipe will produce a 33hz tune. 

dollarlongnecks wrote:
Again, thanks for the help. I'm hoping all this work is worth the effort...

You learned something right? designing w/winisd need advice -- posted image.

"I'm finished!" - Daniel Plainview
dollarlongnecks 
Member - Posts: 9
Member spacespace
Joined: June 03, 2003
Posted: May 06, 2007 at 10:17 PM / IP Logged  

Great, I'm looking forward to throwing this thing together. Just a few last questions...

Can you give me a little info on the fiberglass resin you use for the box? Is this something you spread on the inside of the box?

And in the relation to the ports, when I look at the air velocity graph in WinISD, it looks like it is way above other recommendations I have read, which was to keep it below 110 fps. Should I try to bring this down?

designing w/winisd need advice -- posted image.

And yeah, thanks sedate, I've learned quite a bit. Plus, i like all this design and planning stuff, it's right down my alley.

Page of 2

  Printable version Printable version Post ReplyPost New Topic
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot delete your posts in this forum
You cannot edit your posts in this forum
You cannot create polls in this forum
You cannot vote in polls in this forum

  •  
Search the12volt.com
Follow the12volt.com Follow the12volt.com on Facebook
Wednesday, September 28, 2022 • Copyright © 1999-2022 the12volt.com, All Rights Reserved Privacy Policy & Use of Cookies
Disclaimer: *All information on this site ( the12volt.com ) is provided "as is" without any warranty of any kind, either expressed or implied, including but not limited to fitness for a particular use. Any user assumes the entire risk as to the accuracy and use of this information. Please verify all wire colors and diagrams before applying any information.

Secured by Sectigo
the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
Support the12volt.com
Top
the12volt.com spacer
the12volt.com spacer