Building the 4345/4344

[Ian Mackenzie]

Hi,

Just just looked in BassBox and the stats in there are indeed similar. Oh well the audibility of the issue is certainly real, just the sensitivity was the only thing I could think of at the time to explain it.

Regards Johns Nebel's equation, the other option is to raise the 2122H a notch and the horn and slot in equal incriments.

I just think that when we start comparing models that the "0" positions on the Pads do not necessarily mean "flat" in a particular room and some adjustment of the pads is mandatory for the sweetest balance of lows, mids and hi's.

The 4435 also have the flat power response unlike the 4343 so that blows equivelant pad settings to hell.

Anyways I felt privileged to hear Mint 4343 and 4435's side by side.....a JBL wall of sound..WOW

Ian

[Hofmannhp]

Originally posted by Ian Mackenzie
Under Construction

This thread will be dedicated to those members wishing to construct the vintage JBL 4345/4344 Professional Series Studio Monitors.

Over the next few weeks I will document blue prints (in JBL Blue..LOL) and provide a Step by Step Guide to Enclosure and Crossover Network Design & Construction.
......Ian Mackenzie.

Ian,

sorry....saw this posting today......let me know if I can assist you in this job (I don't wanna disturb your circles with YOUR documents)

HP

PS: thanks for the drawings....I will wait for your reply

[Ian Mackenzie]

Well it does need completing but the interest died off when I made the great voyage to North America in search of the Pass and the Diva.

Now that I have returned and washed my soiled denim from La Honda I will complete the journey here soon enough. Perhaps we should purge this work with the JBL Blue Thread (The Bermuda Triangle) before it gets covered in more graffitti.

Ian

[Robh3606]

Hello Ian

Will have these babies up and running by the weekend. Some odds and ends like wiring in your crossovers. But the cabinets are done and the driver loaded. Let you know how I like them.

Rob

[Ian Mackenzie]

Very nice Robert!



Ian

[Ian Mackenzie]

here are some near field response measurements some of you might find interesting and useful.

All measurements are taken with the drivers on the 4345 baffle with the crossover filters inserted. I did this to create a library of data for when I try to quad amp the system.


This is the 2122 right channel

Ian

[Ian Mackenzie]

The 2122 left channel.

The near field distance is about 1 foot. (30 cm)

Ian

[Ian Mackenzie]

The right channel 2307/2308 horn lense combination.

Ian

[Ian Mackenzie]

The left 2307/2308 horn lense combination

Ian

[Ian Mackenzie]

The 2405 slot right channel.

Ian

[Ian Mackenzie]

The 2405 left channel.

Ian

[Ian Mackenzie]

Here is an updated 2307/2308 response measurement. The 2308 has 4 mm of soft open cell foam packed in the rear of the lense.

I have not done any subjective comparisons yet.

Ian

[Ian Mackenzie]

Here is the full system response at 1.5 metres, gated to minimise room effects. I a reflection free field environment I would expect this to be marginally smoother.

The response about 15 kherts is down a bit, perhaps my 2405 need a some more joules! I plan to have all the compression driivers re gaussed soon.

Ian

[boputnam]

Nice.

Remind us about your measurement microphone - Panasonic, wasn't it?

[Ian Mackenzie]

Its the Panasonic.

Technique matters as much as anything. I am research this and will post some information in a day or two.

Bit like a surveyers or navigators instrument, in the wrong hands and your stuffed.

Ian