Easter project - 2245 subwoofer

[Lee in Montreal]

I started this morning with a cut-up sheet of 3/4" Baltic Birch plywood and a 30"x 60" of 1/2" Baltic Birch for reinforcements

Roughly 36" x 24" x 24" and 10,5cft. Ports are 6" x 16-1/2" an they tune the cabinet to 27Hz I will add 3db bump around 25Hz.


http://img.photobucket.com/albums/v668/Lee_Vuong/JBL parts factory/DSCN2552_zps9bc62be6.jpg

And stopped around 6

http://img.photobucket.com/albums/v668/Lee_Vuong/JBL parts factory/DSCN2570_zpsb63c8b24.jpg

http://img.photobucket.com/albums/v668/Lee_Vuong/JBL parts factory/DSCN2571_zps2b7109de.jpg

I basicaly have to close the top, then clean all the corners and junctions with a router, then stain the plywood. Which I shall do tomorrow before it rains in the afternoon.

More details of the build tomorrow.

[Ear4life]

This looks like a perfect way to spend the Easter days :bouncy:

Looking great! Is it going to be a center placed sub? What amp are you going to use? It reminds me of the 2245h that I have laying around as well.... hmm..

Well... looking forward for the next BUNCH of pictures :)

Regards
Martin

[Lee in Montreal]

Center placed sub peforming in the 20-50Hz range. I closed the lid this morning. I am currently waiting for the hardening lacquer (Shellac) to cure before giving it a second sanding and smoothing out the plywood. Most likely painting tomorrow. While the lacquer is drying, I am also looking for that set of four casters I had removed the other day from my 4520s... Just can' find them. ;)

[johnobub]

how's the progress now? more pictures yet?

[Lee in Montreal]

how's the progress now? more pictures yet?

Shellac hasn't cured yet. ;)

I can't wait to give it a coat of paint and start stuffing them. The cabinet didn't seem big when drafted, but 36x24x24 is serious volume for a home system.

[Lee in Montreal]

I will sand the cab and paint it in black in a few days when the Shellac has 100% cured. In the meanwhile I am making some tests.

http://sphotos-a.ak.fbcdn.net/hphotos-ak-frc1/883153_564405090257530_411380388_o.jpg

[Ear4life]

Nice!

Are you happy with the size and tuning?

Good job! :)

[Lee in Montreal]

Only played a few hours but so far I am happy. The cabinet is rigid enough, and the bass is very low.

[NickH]

Why paint it. I think it looks pretty nice as is. Unless theres some nasty spots on the wood. I kinda like the exposed end grain of plywood. All the layers. Just look neat to me.

Nick

[Ear4life]

I will sand the cab and paint it in black in a few days when the Shellac has 100% cured. In the meanwhile I am making some tests.

http://sphotos-a.ak.fbcdn.net/hphotos-ak-frc1/883153_564405090257530_411380388_o.jpg

How does the 2245 go with the 2226? In my world they do "sound" different. Can you make them work together?

[Lee in Montreal]

How does the 2245 go with the 2226? In my world they do "sound" different. Can you make them work together?

They don't overlap. The 2245 does 20 to 50Hz while the 2226 does 50Hz and up. This is exactly because each of the drivers sound differently, and have there specific strength that they work well together. The lower bass from the 2245 and the mid/upper bass from the 2226 make a great team. ;) Basically, I tune the 2245 so that I don't hear it. Only feel it.

[Lee in Montreal]

I am working at gradually making the 2245 disapear. Sounds good so far. I love the floor shaking feel on some musical cuts... I can't believe there were monitors with a 2245 in each. The JBL 4345 were monsters.

[Lee in Montreal]

Now I need some help from people using a DCX 2496. How do you plumb properly a two-way plus sub in the active crossover and do the summing for the sub?

[grumpy]

... more than pg21 of the user manual?

[Lee in Montreal]

... more than pg21 of the user manual?


I did the 6.2 set-up on page 19. The problem is that I can't adjust the sub independently of the regular bass channel.

Lee

[RedCoat23]

I am working at gradually making the 2245 disapear. Sounds good so far. I love the floor shaking feel on some musical cuts... I can't people there were monitors with a 2245 in each. The JBL 4345 were monsters.

This begs an interesting question, is music today mixed with the prevalent 6.5 - 8 inch woofer as the standard driver in most home loudspeakers? Such that when modern music is played through something like the 4345 it can sound overblown? Not owning or having listened to one I can't comment though. Or am I pointing to an issue that just isn't there? (without rehashing that whole 'loudness wars' issue again) - I have enough components to build a pair, so I'm wondering what I'll experience when the time comes...

[BMWCCA]

This begs an interesting question, is music today mixed with the prevalent 6.5 - 8 inch woofer as the standard driver in most home loudspeakers? Such that when modern music is played through something like the 4345 it can sound overblown? Not owning or having listened to one I can't comment though. Or am I pointing to an issue that just isn't there? (without rehashing that whole 'loudness wars' issue again) - I have enough components to build a pair, so I'm wondering what I'll experience when the time comes...

You may actually hear a recording of a double bass that sounds like hearing the instrument in person.

[Lee in Montreal]

You may actually hear a recording of a double bass that sounds like hearing the instrument in person. And they are active with a lot of correction built-in (welcome to the digital world). I worked with some Genelecs a few years ago and they were impressive for the size.

[RedCoat23]

You may actually hear a recording of a double bass that sounds like hearing the instrument in person.
Now that I can get onboard with :) I just need to stop procrastinating and get on with building them :yes:

[BMWCCA]

Now that I can get onboard with :) I just need to stop procrastinating and get on with building them :yes:

I had the bass player from this duo over to the house two-weeks ago and the smile on his face listening to the 4345s told the story.

58543

I stopped short of playing his album for him though. I tried that with Jesse Winchester playing a live track back to him on my cell phone and he just cringed. :o:

[Ear4life]

So... Now must be the time for some pictures again :D

Did you manage to make that big 18" sub disappear?

[Lee in Montreal]

So... Now must be the time for some pictures again :D
I am waiting for some warmer and drier weather. There's currently a cold/windy front. Then I will move the cabinet outside, sand it, stain it and paint the face satin black to blend with the other speakers. I am using this 28" tall (with casters) box as my TV stand. The bottom of the TV screen lines up with the bottom of the 2360 horns. The cabinet is rigid enough not to shake the TV. I atched "Gangster Squad" the other night and the sound and physicality were impressive. I know I can get more 20-30Hz range from a W15GTi, but it would also require more amp.

[4313B]

W15GTiI knew this thread would go straight to hell at some point.

Those things they sell at Parts Express that people shove up their bums put out more in the 20-30 Hz range too.


Nice quick 2245H subwoofer project worth owning though!


Ports are 6" x 16-1/2" an they tune the cabinet to 27Hz I will add 3db bump around 25Hz.The bump frequency should be set at the tuning frequency of the enclosure. There is no protection for the transducer below the tuning frequency of the enclosure.

If you really want a boost at 25 Hz then tune the enclosure to that frequency too.

If you want more output at 20 Hz, then tune the enclosure to that frequency and apply the boost at that frequency.

[Lee in Montreal]

The bump frequency should be set at the tuning frequency of the enclosure. There is no protection for the transducer below the tuning frequency of the enclosure.

You are correct as it allows to limit the driver's excursion. According to this principle, if the cab is tuned to 27Hz, then I should bump 27Hz. But for sound quality, I could do otherwise and tune lower, at the expense of higher excursion. Isn't the B460 an 8cft cabinet tuned to 30Hz, yet has a 6db bump at 26Hz?

BTW Two ports tune the cab to 27Hz, but one port only tunes to 16Hz. Sure it is lower, but I also lose a lot of content above. So, I don't think I'll go there. At least not with this driver. And also, I am currently crossing the 2245 at 50Hz, yet have tried to cross at 100, and 200Hz. Anything above 100Hz sounded very muddy. Yerk. It definitively cannot be used as part of a two way system... ;-)

I have printed this sticker and it will proudly be applied to the front of the cab. ;-)

58576

[Lee in Montreal]

BTW I made those cabinets for 10cft because it was the maximum volume I could fit by using a single sheet of 4'x8'

Side panels are 23-3/4" x 23-3/4"
Front and rear panels are 34-1/2" x 23-3/4"
Top and bottom panels are 36" x 23-3/4"

Internal measurements are 34-1/2" x 23-3/4" x 22-1/4" for a net volume of 10.67cf (302 litres) to which the volume of the woofer must be substracted (0.3cft) as well as the bracing and your tubes.

[4313B]

to which the volume of the woofer must be substracted (0.3cft) as well as the bracing and your tubes.Usually fiberglass insulation negates a good portion of that internal displacement.

Years ago I showed that with a 9 cu ft 2245H subwoofer build. The gross volume of the box was something like 9 cu ft. The net volume was something just under 8 cu ft with the bracing, ducted ports and 2245H displacement subtracted. Adding in the fiberglass insulation negated virtually all of the displaced volume yielding a net effective volume of just over 9 cu ft. This is why alot of the JBL enclosures don't really add up to their published volumes or dimensions. One has to use the tuning formula backwards to arrive at the net effective volume, since the ducted ports and tuning frequency are known quantities.

What is the measured Fb of the enclosure?


Isn't the B460 an 8cft cabinet tuned to 30Hz, yet has a 6db bump at 26Hz?You might be thinking of one version of the 4645. The B460 and original 4645 were 25 Hz boxes. 2245H's kept blowing up in the 4645 boxes so JBL tuned them up to 30 Hz. With the introduction of the 2242H, JBL was able to tune the box back down to 25 Hz.

[Lee in Montreal]

Usually fiberglass insulation negates a good portion of that internal displacement. There's another school of thinking that supports that proper insulation actually increases net volume.

BTW I don't use fiberglass insulation. I don't enjoy breathing that stuff. I use either high density foam, and or natural fibers.

Also, that same cabinet can be used to house a pair of 2226, 2225 or 2235. That would be an ideal volume. And two drivers together will mutually couple and give you free 3db, which you can use on the bottom octave, and tame the rest by 3db...

[pos]

have tried to cross at 100, and 200Hz. Anything above 100Hz sounded very muddy. Yerk. It definitively cannot be used as part of a two way system... ;-)

It needs to be raised off the floor a bit more if you want to go above 100Hz. It should be on par with a 2235Hz up to 300Hz.

Great sticker by the way :)

[4313B]

There's another school of thinking that supports that proper insulation actually increases net volume.Well it really doesn't matter what school supports that, it actually happens. That's what I meant by the fiberglass negating the displacement of ducted ports, bracing, transducers, etc.

But there is a point of diminishing returns wherein the system ends up sounding dead.

BTW I don't use fiberglass insulation. I don't enjoy breathing that stuff. I use either high density foam, and or natural fibers.Yeah, I'm getting tired of the fiberglass myself.
It needs to be raised off the floor a bit more if you want to go above 100Hz. It should be on par with a 2235Hz up to 300Hz.Soffit mounting for the win? :p

Yeah, the old 2235H and 2245H can load up pretty bad with boundary reinforcement. The W15GTi is far worse. Put that thing in a corner in a house and stuff is going to start breaking everywhere. I loathe that transducer for home subwoofer use. It's just awful. Works great in a '65 Impala though. :rotfl:

[JuniorJBL]

. Works great in a '65 Impala though. :rotfl:


Just put 6 of um in there and it will be lowered as well!!

Song plays "All my friends know the low rider"

http://www.youtube.com/watch?v=8NkgiFHEm0Y

:D

[4313B]

Thanks! :)

Beats all hell out out caulk videos! :rolleyes:

[rdgrimes]

BTW I made those cabinets for 10cft because it was the maximum volume I could fit by using a single sheet of 4'x8'


I admire this kind of self-confidence. While I know for a fact that I would have needed 2 sheets to get the job done, what with mistakes and such. :o: