porting sugestion

[kartsmart]

I am in the works of building some 2245 subs, but came across a great buy on 4 8cu ft boxes for far less then I could build one of them and nicely made too . The front panel measures 21.5 w x 33" H x 21.5 D with the cut out for a 18" centered in panel and 4 4" ports near each corner forming what looks like a x pattern . my question is would the 4 ports be ok or are they to small and would make port noise? Or go through all the work to make a new ft panel ?
The next question is I see that the early subs were tuned to 20 HZ and later tuned them at 25 HZ to protect the longevity of the driver. I plan to mainly use these for music play back. At the outrages prices to recone these would it be best to tune these at 25 HZ with a low filter cutoff ?
Question 3 I tried a few different programs to calculate what the port length would be with the 4 4" ports and come up with a different answer one was 25" if right I only have 21" depth in the box. what answer do you all get for port length ?
thanks advance

[pos]

The original 4645 is 8cu ft and has 3 4" ports and was tuned to 30Hz.
I have two such subs at home and cannot ear port noise at any usable level.

I think 25-30Hz is a good tuning for music use, and you can apply eq to remove any unwanted room gain.

[maxwedge]

The next question is I see that the early subs were tuned to 20 HZ and later tuned them at 25 HZ to protect the longevity of the driver. I plan to mainly use these for music play back. At the outrages prices to recone these would it be best to tune these at 25 HZ with a low filter cutoff ?

I fairly sure that that is incorrect. The early 2245 subs were 25hz and the later 30hz. I have a pair of 4645 cabs that came with 2245's and they are tuned at 30hz. For home use, I would tune them 25~28hz with a 20hz 2nd order HP for protection. For sound reinforcement use 30hz cabinet tuning.


Question 3 I tried a few different programs to calculate what the port length would be with the 4 4" ports and come up with a different answer one was 25" if right I only have 21" depth in the box. what answer do you all get for port length ?
thanks advance
That's why you'll want 3, because the tubes will be shorter. The only advantage of 4 tubes will be less port noise, but its more of a factor if you're cranking them near their max.
You could use curved tubes.;)

[kartsmart]

That's why you'll want 3, because the tubes will be shorter. The only advantage of 4 tubes will be less port noise, but its more of a factor if you're cranking them near their max.
You could use curved tubes.;)
I am not sure what the length should be 4 sure ?

[maxwedge]

I am not sure what the length should be 4 sure ?
I use BB6P and what comes out with 8 cu ft and typical fill for 25hz is:

4x4" ports at 21.5"
3x4" ports at 15.1"

The program comes out really close.

[Lee in Montreal]

Here's an online software to calculate port length.

http://www.psp-inc.com/tools.html

[kartsmart]

I use BB6P and what comes out with 8 cu ft and typical fill for 25hz is:

4x4" ports at 21.5"
3x4" ports at 15.1"

The program comes out really close.



It looks like 3 ports will do, thanks for checking :)

[maxwedge]

You're welcome.

[kartsmart]

I bought 4 2245 drivers from the audio auction , at the time of the purchase I was insured that they were 2245 with jbl cones so thinking these were the real 2245s for 150.00 ea I jumped on the deal and bought 4 what a deal, as it turned out by the time I received the shipment the add was changed to read 2245 with 2240 cones.After a week of not answering E-mails and calls , I finally talked to him and said he would return them if i pay the shipping , so now I would have had 130.00 in shipping to get out of this bad deal. So I kept them and using 2 of them as expensive cores to re-cone. Audio Auction shame on you this is bad business !
So I will be using 2 of the re-cones In the sub boxes that I bought for my subs, then I thought I might use the other 2 2240s in the other 2 boxes I have. It looks like these caps are tuned app. 45 HZ 2240s in a 8cu ft box tuned at 45 would be a good start ? then I could sell these off and re-coop my losses. :confused:

[Lee in Montreal]

You should ask them for a partial refund as they sell the 2240s at $120 each on their own website (or at least they did a week ago).

The 2240 have Fs30Hz. Maybe if you don't use them for uber loud as for PA, you can tune the box to 30/35Hz.

[kartsmart]

You should ask them for a partial refund as they sell the 2240s at $120 each on their own website (or at least they did a week ago).

The 2240 have Fs30Hz. Maybe if you don't use them for uber loud as for PA, you can tune the box to 30/35Hz.
yes I can easily change the port length, It has 4" PVC so all I would have to do is use a coupler and add the length. So you think 35HZ would be closer. For what I payed for these caps and all the work it saved me there is room for a little TLC :p
As for The Audio Auction being able to smear his name here is satisfying :applaud:

[Lee in Montreal]

yes I can easily change the port length, It has 4" PVC so all I would have to do is use a coupler and add the length. So you think 35HZ would be closer. For what I payed for these caps and all the work it saved me there is room for a little TLC :p
As for The Audio Auction being able to smear his name here is satisfying :applaud:

Actually, you could tune the cabinet to the driver's resonance frequency at Fs30Hz. Experiment. Have fun.

Your experience has me worried about Audio Auction now. :(

[maxwedge]

I bought 4 2245 drivers from the audio auction , at the time of the purchase I was insured that they were 2245 with jbl cones so thinking these were the real 2245s for 150.00 ea I jumped on the deal and bought 4 what a deal, as it turned out by the time I received the shipment the add was changed to read 2245 with 2240 cones.After a week of not answering E-mails and calls , I finally talked to him and said he would return them if i pay the shipping , so now I would have had 130.00 in shipping to get out of this bad deal. So I kept them and using 2 of them as expensive cores to re-cone. Audio Auction shame on you this is bad business !
So I will be using 2 of the re-cones In the sub boxes that I bought for my subs, then I thought I might use the other 2 2240s in the other 2 boxes I have. It looks like these caps are tuned app. 45 HZ 2240s in a 8cu ft box tuned at 45 would be a good start ? then I could sell these off and re-coop my losses. :confused:
Those are the same ones that were just on ebay. I almost bought a pair.
http://www.audioheritage.org/vbulletin/showthread.php?30646-Does-it-look-like-a-2245-to-you-%29

When you're playing with your ports use duct tape on the couplers until you get the tuning right. I'd try 30hz first with those 2240's

[maxwedge]

3x4" ports at 8.87" long for 30hz 8 cu ft box and

4x4" ports 13.2" for 30hz will now fit in your cab.

[Lee in Montreal]

May I add that the 2240h woofers may have way more hifi potential for home use than we think. It sure is missing the 20-30Hz range, but that band is rarely used unless you listen to techno and electronic music. The 2240's suspension is not as fragile as the 2245's and will last longer.

Basically, the 2240 is a great driver and an underdog. $150 per unit with original JBL cones is still a great bargain. :applaud:If you have four of them, then build two TCBs (bandpass) for plenty of infrabass at high volume without risking over excursion or knocking the coils. :eek:

[kartsmart]

May I add that the 2240h woofers may have way more hifi potential for home use than we think. It sure is missing the 20-30Hz range, but that band is rarely used unless you listen to techno and electronic music. The 2240's suspension is not as fragile as the 2245's and will last longer.

Basically, the 2240 is a great driver and an underdog. $150 per unit with original JBL cones is still a great bargain. :applaud:If you have four of them, then build two TCBs (bandpass) for plenty of infrabass at high volume without risking over excursion or knocking the coils. :eek:



2 of the 2240s are sent out to re cone as 2245s, as for the other 2 will keep as 2240s, how high will these play before they start to sound ugly ? never used them or heard them. was thinking for the 2245s in 8cu ft caps I could elbow the ports so I could use 4 ports but don't know what the side affects would be bending the ports ?

[kartsmart]

[QUOTE=maxwedge;311493]Those are the same ones that were just on ebay. I almost bought a pair.
http://www.audioheritage.org/vbulletin/showthread.php?30646-Does-it-look-like-a-2245-to-you-%29

Yep that is what I done , and yes there was no hint of them as 2240s then changed his add later. I see he had a bunch of 2123s but now see that he is selling E-110s I wounder If he had done the same trick on these ?

[kartsmart]

May I add that the 2240h woofers may have way more hifi potential for home use than we think. It sure is missing the 20-30Hz range, but that band is rarely used unless you listen to techno and electronic music. The 2240's suspension is not as fragile as the 2245's and will last longer.

Basically, the 2240 is a great driver and an underdog. $150 per unit with original JBL cones is still a great bargain. :applaud:If you have four of them, then build two TCBs (bandpass) for plenty of infrabass at high volume without risking over excursion or knocking the coils. :eek:


If I was to run subs under the 2240s now what port HZ would be best ? Just playing for now.

[kartsmart]

I have a QSC PLX 2402 amp http://media.qscaudio.com/pdfs/plxuser.pdf and was wounding if it would be a suitable amp to drive the 2245 subs

[maxwedge]

2 of the 2240s are sent out to re cone as 2245s, as for the other 2 will keep as 2240s, how high will these play before they start to sound ugly ? never used them or heard them. was thinking for the 2245s in 8cu ft caps I could elbow the ports so I could use 4 ports but don't know what the side affects would be bending the ports ?
I think you'll like the 2245's better than the 2240's.;)
Keep it simple, just use the 3 ports if you're tuning down to 25hz. I use 3 and can't hear any port noise.

Scott

[maxwedge]

[QUOTE=maxwedge;311493]Those are the same ones that were just on ebay. I almost bought a pair.
http://www.audioheritage.org/vbulletin/showthread.php?30646-Does-it-look-like-a-2245-to-you-%29

Yep that is what I done , and yes there was no hint of them as 2240s then changed his add later. I see he had a bunch of 2123s but now see that he is selling E-110s I wounder If he had done the same trick on these ?

He did the same with the ebay ad, changed it later!:(

[kartsmart]

I think you'll like the 2245's better than the 2240's.;)
Keep it simple, just use the 3 ports if you're tuning down to 25hz. I use 3 and can't hear any port noise.

Scott

I like simple :)
As I have said the 2240 will be put in spare caps then sold to recoup my losses .

[1audiohack]

I like simple :)
As I have said the 2240 will be put in spare caps then sold to recoup my losses .

I am casually looking for a nice 2240 or two, if and when you decide to sell them please let me know.

[gferrell]

May I add that the 2240h woofers may have way more hifi potential for home use than we think. It sure is missing the 20-30Hz range, but that band is rarely used unless you listen to techno and electronic music. The 2240's suspension is not as fragile as the 2245's and will last longer.

Basically, the 2240 is a great driver and an underdog. $150 per unit with original JBL cones is still a great bargain. :applaud:If you have four of them, then build two TCBs (bandpass) for plenty of infrabass at high volume without risking over excursion or knocking the coils. :eek:


Good point. I don't think I can even hear 20-30Hz only feel it.

[maxwedge]

You pick. Orange is 2245 and red is 2240, normalized of course.;)
Same 8 cu ft box tuned optimally for each driver...25hz for 2245 and 29.3hz for the 2240. I see 3db+ at 40hz and 4-5+at 50hz:dont-know:
http://i76.photobucket.com/albums/j7/maxwedge572/Audio/JBL2245vs2240.jpg

[kartsmart]

You pick. Orange is 2245 and red is 2240, normalized of course.;)
Same 8 cu ft box tuned optimally for each driver...25hz for 2245 and 29.3hz for the 2240. I see 3db+ at 40hz and 4-5+at 50hz:dont-know:
http://i76.photobucket.com/albums/j7/maxwedge572/Audio/JBL2245vs2240.jpg

have you done anything about eq for the 2245s

[maxwedge]

have you done anything about eq for the 2245s
Yeah but I use my big system for music only so it doesn't matter much imo. You can do a 3-6db bump at 25hz and then you should run a high pass 2nd order at 20hz to help keep them safe.

I have a pair of sub1500 in sealed boxes for HT. Those blow walls down with my qsc rmx2450 in mono!:bouncy:

[Eaulive]

You pick. Orange is 2245 and red is 2240, normalized of course.;)
Same 8 cu ft box tuned optimally for each driver...25hz for 2245 and 29.3hz for the 2240. I see 3db+ at 40hz and 4-5+at 50hz:dont-know:
http://i76.photobucket.com/albums/j7/maxwedge572/Audio/JBL2245vs2240.jpg
The 2240 has 3dB more sensitivity than the 2245, so in practice the red line should be above the orange line for most of the chart, and about the same at the lower end.

The 2245 will be flatter on the low end, but wont necessarily have more gain that the 2240.

Same behaviour can be observed between the 2225 and the 2235.

[maxwedge]

The 2240 has 3dB more sensitivity than the 2245, so in practice the red line should be above the orange line for most of the chart, and about the same at the lower end.

The 2245 will be flatter on the low end, but wont necessarily have more gain that the 2240.

Same behaviour can be observed between the 2225 and the 2235.
I agree, but if kartsmart is using these in his home the 2245 will blow the doors off of any other 18. Come on, I swapped out 2242's for 2245's (with aftermarket cones even!) and the bottom end is superior! I needed to run my sub1500's with the 2242's to bring up the bottom, or use a bunch of eq. Efficiency isn't everything, especially in your living room.

Sound reinforcement duty is a different situation.;)

[kartsmart]

I agree, but if kartsmart is using these in his home the 2245 will blow the doors off of any other 18. Come on, I swapped out 2242's for 2245's (with aftermarket cones even!) and the bottom end is superior! I needed to run my sub1500's with the 2242's to bring up the bottom, or use a bunch of eq. Efficiency isn't everything, especially in your living room.

Sound reinforcement duty is a different situation.;)

yes I will be using these in my home ( the 2 car atached garage - my part of the house ) my wife kicked me and the system out to the garage because I was knocking her **** off the walls, thats why I need these subs - so I can still knock her s*** off the walls from the garage :bouncy: what you think ?

[Eaulive]

I agree, but if kartsmart is using these in his home the 2245 will blow the doors off of any other 18. Come on, I swapped out 2242's for 2245's (with aftermarket cones even!) and the bottom end is superior! I needed to run my sub1500's with the 2242's to bring up the bottom, or use a bunch of eq. Efficiency isn't everything, especially in your living room.

Sound reinforcement duty is a different situation.;)

Of course you're right, in home a 2245 will probably go lower, I just wanted to point out the discrepancy of the chart ;)

[pos]

the 2245 will blow the doors off of any other 18.
One potential contender I'd like to try is the TAD TL1801.

[maxwedge]

Of course you're right, in home a 2245 will probably go lower, I just wanted to point out the discrepancy of the chart ;)
I said that the chart was normalized?:dont-know:

[maxwedge]

yes I will be using these in my home ( the 2 car atached garage - my part of the house ) my wife kicked me and the system out to the garage because I was knocking her **** off the walls, thats why I need these subs - so I can still knock her s*** off the walls from the garage :bouncy: what you think ?
Sounds like a plan to me!:applaud:

[maxwedge]

I agree, but if kartsmart is using these in his home the 2245 will blow the doors off of any other 18.


One potential contender I'd like to try is the TAD TL1801.
You took my statement out of context. :(

Ok well yeah, there are a lot of great speakers out there so maybe my statement was a little over the top, Sorry. That Tad looks nice, with a low fs too.:)

[pos]

At home for me too!
I have a pair of 2245H, but I would like to test these TAD drivers, as Westlake see them as upgrades to the 2245 in their SM1 speakers

[Eaulive]

I said that the chart was normalized?:dont-know:

Ah, indeed :p

[kartsmart]

The 2240 has 3dB more sensitivity than the 2245, so in practice the red line should be above the orange line for most of the chart, and about the same at the lower end.

The 2245 will be flatter on the low end, but wont necessarily have more gain that the 2240.

Same behavior can be observed between the 2225 and the 2235.


I am assembling a pair of 2240H in 8 cu ft caps this weekend 4 ports 4" pvc what port length do you suggest, I came up with 13.5"

[Lee in Montreal]

I am assembling a pair of 2240H in 8 cu ft caps this weekend 4 ports 4" pvc what port length do you suggest, I came up with 13.5"

There are two schools of thought when it comes to tuning these ports. One school says to tune the ports to the cabinet's resonance frequency (and I don't remember what's the resonance of 8cft). The other school says to tune to the driver's Fs, which is 30Hz in your case.

For Fs30Hz= four 4"x 15.9"

If you block one of the four ports, but keeping the same length, then the new tuning frequency becomes 26Hz, which is 2245 territory.

[Ruediger]

There are two schools of thought when it comes to tuning these ports. One school says to tune the ports to the cabinet's resonance frequency (and I don't remember what's the resonance of 8cft). The other school says to tune to the driver's Fs, which is 30Hz in your case.
<snip>

A cabinet does not have a resonance frequency. A cabinet together with a port does have one. The air in the cabinet is a spring, and the air in the port is a mass.

ruediger

[Hoerninger]

There are two schools of thought when it comes to tuning these ports. One school says ... The other school says ...
A more elaborate theorie you cab find here
http://www.xlrtechs.com/dbkeele.com/PDF/Keele%20%281972-05%20AES%20Preprint%29%20-%20Vented%20Loudspeaker%20A%20Restatement.pdf
with lots of alignment tables. :thmbsup:
____________
Peter