JBL 4355 clone with different woofers

[RMC]

Add to the previous list of names to look at: Eminence, Peavy, SB Acoustics Audience (new pro series they started) and even Peerless launched a pro series. That's a lot of places to look at and potentially find a winner...

Richard

[RMC]

Came back to me the 2202 replacement mentioned before was the B&C 12PE32-8.

Not as ruler flat response but pretty smooth (say +/- 2 db) between the 290hz and 1.2 khz crossover points.

Has 2 db higher sensitivity rating than 2202. So it is possible to have pretty flat response with high sensitivity. Higher driver sensitivity than one needs is usually a lesser problem than having one with a too low number. It also has lower cone mass than the 2202.

There's certainly potential here as a 2202 replacement, however i wouldn't say right away yes this is the one to get, though quite interesting, i'd still want to see some other possible substitutes before making any decision, as other criterias may be considered by a user such as availability, pricing, etc.

I haven't started a search for some 2202 equivalent simply because i don't need it, and have no project in sight that would require this driver. If the need ever arises i know where to look for those. Picture is from Canada's qcomponents.ca, just an example, no affiliations. But i noted they reduced their prices on a number of drivers, don't know why, including that B&C model.

Richard

[audiophile.1963]

On Thursday I found a pair of 2202h in very good condition, the latest version
Giuseppe

[grumpy]

A nice find. Congratulations

[audiophile.1963]

Had planned to reply. Saw Earl beats me to finish line and that's fine, saves me some work. Plus mostly agree with his comments anyway.

The only observation i have with the vent is that the area chosen by user is below the min. recommended by Winspeakerz, this by a notable margin of 10.5 or so sq. in. (34.2 min. recom. - 23.86 sq. in. from user tube).

The 14 cm (5.5") vent meets JBL's old rule of thumb of one third driver diameter, however since it was enacted years ago it may not be enough anymore for more modern high power drivers.

At high drive levels that port might experience some difficulties. The cab won't turn into a pumpkin for this, simply important to know and drive accordingly... 2235 Pe 150W; 2226 Pe 600W. The software takes that into account.

Btw if the OP can high-pass filter his woofers at say 35 hz with steep slope he might be able to improve somewhat his power and excursion situation shown on the graph.

Pic shows, like in post #13, 2226 in 5 cu.ft. box tuned to 40 hz, 300W, but this time with the vent details based on user tube dia. (i get same length as Earl), but vent area is the concern in case he's ambitious power wise.

Attachment 89332

In Italy I have only found tubes with an external diameter of 14 cm, but an internal 13 cm. Is that okay anyway? Do I have to do it a little longer and how much?
Giuseppe

[RMC]

That means your tubes are a centimeter thick! WOW. I have some very thick cardboard tubes and they're not even 1 cm (about 6-7 mm).

Since vent area is reduced the tube has to be shorter in order to keep the same box tuning frequency. I've switched my Speaker Design software to Metric mode to make it easier on you. See picture attached.

With the new inside diameter you're giving me the vent length (Lv) needs to be a little shorter at 0.082 meter long (or 3.228 inches, so say 3.25"). From the previous number they had 4" long (101 mm). Naturally the vent's air passing capability is not improving.

Richard

[grumpy]

--> 5mm

[RMC]

Thanks Grumpy. Yeah i stand corrected, dumb me, it is 5 mm thickness... But my thick cardboard ones do have 6-7 mm, got this from a butcher's empty roll of Saran Wrap type thing.

[audiophile.1963]

That means your tubes are a centimeter thick! WOW. I have some very thick cardboard tubes and they're not even 1 cm (about 6-7 mm).

Since vent area is reduced the tube has to be shorter in order to keep the same box tuning frequency. I've switched my Speaker Design software to Metric mode to make it easier on you. See picture attached.

With the new inside diameter you're giving me the vent length (Lv) needs to be a little shorter at 0.082 meter long (or 3.228 inches, so say 3.25"). From the previous number they had 4" long (101 mm). Naturally the vent's air passing capability is not improving.

Richard

Hi, I have looked at your graphs carefully and there is something that is not correct following your reasoning (I hope I have not read it wrong). Three simulations were made with three tubes of different diameters: diameter 5 "(12.7 cm) long 11.44 cm diameter 5.12 "(13 cm) long 8.2 cm diameter 5.5 "(13.97 cm) long 10.2 cm Following your reasoning, if the diameter of the pipe decreases, the length also decreases: why then is the first longer than the second? I understand that these are small things but I would like to understand. In the end yesterday I bought the tube and the correct internal diameter is 13.5 cm. I had mistakenly trusted my plumber.
Giuseppe

[RMC]

I just checked my vent length posts again. There appears to be some error(s) and misunderstanding on your part.

Larger area vent tunes higher, smaller area tunes lower. Moreover, shorter vent length tunes higher and longer one tunes lower.

So in one case you reduced dia. from 14 cm to 13 cm, therefore tuning lower, then in order to keep the same tuning frequency as before you also have to reduce tube length.

RE "diameter 5 "(12.7 cm) long 11.44 cm"

This is all wrong. Check pics again post #20. What i presented is TWO 5" tubes with 11.44 INCHES length (not cm), and that applies to number of drivers indicated at bottom left of pics: ONE driver. Yes, two 5" ports per 2226. This to meet vent air flow requirements for each 600W woofer (not 150W like 2235). The first tubes were longer because of double vent area with TWO tubes...

I realize a number of people here have difficulty in understanding how box tuning works, and regularly ask for proper vent dimensions to tune their project box. Today with computer programs its easy to know the answer, however that doesn't tell you how to get there and the implications of each move (larger, longer, shorter, etc.)

The best school to learn and understand the hows and whys of this is having to do it manually, as i did in the old days, with formulas and equations, and later with box tuning charts & graphs, way before the PC became popular.

[audiophile.1963]

Hi everyone, the 4355 prototype is almost finished but I have to solve a problem. The fixing holes to the cabinet in the JBL 2311 horn are not accurate, does anyone have a precise drawing of this tro, ba with the exact distances between the holes? Thanks

[jbl4ever]

Hi Giuseppe, scroll down to post #6 for your information

http://www.audioheritage.org/vbullet...2-Bolt-Pattern

[audiophile.1963]

Hi Giuseppe, scroll down to post #6 for your information

http://www.audioheritage.org/vbullet...2-Bolt-Pattern

Thank you very much!

[audiophile.1963]

... and the profile of JBL 2311 is conic or exponential?

[RMC]

In a recent 2311 search i saw some of these for sale and recall that one or two of them had pretty good pictures. This might help you figure it out, in absence of the actual info.

I don't remember on which web site(s) it was seen, but if you Google JBL 2311 you might find the pics since this is what i used for my search.

Richard