Building the 4345/4344

[boputnam]

It depends...

Your sound card must be full duplex, and have stereo inputs. My laptop failed that test, requiring I go through three different USB preamps to find one that worked (with my laptop). My laptop had some "issues" with the SmaartLIVE drivers - particularly with a Delta Audio USB device otherwise well regarded. I could not sort-out the problem, and had to upgrade to the "USB Pre" - a phenomenal (but pricy...) device that has two XLR mic inputs (with gain control), and numerous other flexibility. The USB Pre is co-sold on the SIA site for an otherwise un-matched price, but is, as I say, still pricy. Were I not using it twice a month live (and frequent tweaking our rehearsal studio), it would have been hard to justify.

You must be able to:

1) input the Pink Noise into the preamp (output from SmaartLIVE).
2) pre the EQ, sample the pre-amp output (whether Pink Noise or other material) - this is the reference signal. I usually grab it from either a "Y" off pre-amp output, or use the EQ parallel input as a source...
3) sample the ambient output of the speaker (one side at a time) of whatever source you are using (use a flat-response acoustic mic)
4) measure the variance between the reference signal and the ambient mic, and adjust the EQ for flat.

Hmm-mm-good...

[Robh3606]

Thanks Bo

I will have to give it a whirl and get back to you. My card is full duplex with stereo inputs so it should work.

Rob

[Hofmannhp]

Originally posted by Robh3606
Thanks Bo
With Smart Live can you configure your windows mixer Mic Input as a channel?? I have put off loading the trial software so I can have the most productive time with it. I have a phantom power box for my measurement mic but no mic preamp unless I use an input to an old casette deck as my preamp and just monitor that as a second channel. Can you do it with just the sound card???
Rob

Rob and Bo,

I arrived exactly at the same point as Rob.
The problem is:
Connection of the very linear measurement mic to the PC system.
I tried it first with the soundcard mic input ...-> very poor.
After building a phantom power source for the balanced mic out, I tried some prof mic amps (V676a) but there the frequ resp. is also cutted near 35Hz and 15kHz.
Now I decided, to develop a special mic preamp with the best parts available for less noise and max linearity.
The magic part is a matched transistor pair called LM 394.
My benchmark here is min 90dB S/N with + 34dBgain and a linear frequency response from 5Hz to 40KHz.
If you use any of the equipment like cassette deck or.... as a mic preamp, the main frequency response between 18 and 50Hz is only a trend.
If there's any interrest in such a mic preamp (when ready and tested) let me know.
HP

[boputnam]

HansPeter...

You sir, are quite correct. I found that using the laptop on-board sound card gave poor results. And, in-fact the best laptop soundcard is pathetic quality, unable to do what is needed. Some PC cards are plenty good, and capable, but I needed remote capability.

Sound Devices' USBPre - the merits of which I've posted before - was my final solution after two other devices failed to give the flexibilty and/or had driver conflicts. All-in-all, I'm really glad everything else failed, because the USBPre has proven perfectly designed for the SmaartLIVE Transfer function application (and RTA, as well), in-that it gives you gain control over both the reference and measurement signals to ensure your measurements (and adjustments) are relevant and accurate.

[Robh3606]

Don't load new software after 11pm. I was playing until about 2:30 last night before I realized the time. It works just fine with my soundcard and measurement mic. Very powerful sofware. Spent a hour doing sine sweeps in 1/12 octave monitoring SPL looking for room modes. Very educational also confirms my Behringer the two are damn near exact is 1/3 octave RTA mode. Have to play more. Thanks Bo for the help.

Rob

[boputnam]

Rob...

I've been thinking about your post - in-particular tonight listening to the fruits of my re-EQ last night.

These four-way studio monitors are tricky. They certainly can be set-up to great satisfaction vis-a-vis comparisons to "ordinary" (not meant in a demeaning way...) cabinets. It will amaze your friends. However, there is some astonishing JBL engineering evident when these are EQ'd proper. Investing in accurate and suitable test-gear seems a "must" if one is to tame a four-way to the acoustic response of the room they're in, and really hear what they are capable of. Period.

I loved the 4345's the first time I heard them. Today, I marvel ever-more at their definition, clarity, voicing, and depth of soundstage - characteristics that are optimized by test-gear equal to the quality of the 4345's, and up for the challenge.

Do not under-invest in your test gear, even if only used a few times a year.

'nuff said...

[Ken Pachkowsky]

Hmmm......Loved them the first time I heard them. Now they sound better.....hmmmmm.

Could not resist BoBo

[boputnam]

Originally posted by Ken Pachkowsky
Now they sound better...

Not quite, my audio-addicted friend... "Today, I marvel ever-more..." is/was the phrase, and you know better than I how important is the set-up.

Why, by now, you must have had to elevate the bed to stuff all your test gear beneath!!

[4313B]

"However, there is some astonishing JBL engineering evident when these are EQ'd proper. Investing in accurate and suitable test-gear seems a "must" if one is to tame a four-way to the acoustic response of the room they're in, and really hear what they are capable of. Period."

We've talked about this in several versions of the forum and I don't think it can be stressed enough. "Understanding what you are dealing with." It's printed in several JBL publications.

I can't count the number of people who've maligned JBL Studio Monitors over the years. Every single one of them tried to use a 43xx in their home. They were all plug and play types with virtually no concept of the kind of loudspeakers they were dealing with. Their negative experiences were directly related to their attitudes that if they expended the extra effort to spend x amount of dollars on a JBL Studio Monitor then it should just shake right out of the shipping carton and kick major ass. Never mind that many of their rooms utterly sucked in the acoustics department.

It isn't just the 4-ways, the 3-ways and 2-ways like special consideration too. Systems like the 4331 and 4333 can sound very, very good. They can also sound downright awful. It's the user's choice as to how much effort they want to put into the end result. The Studio Monitor should be one of the tools in the bag, not the only tool in the bag.

[boputnam]

Originally posted by Giskard
"However, there is some astonishing JBL engineering evident when these are EQ'd proper. Investing in accurate and suitable test-gear seems a "must" if one is to tame a four-way to the acoustic response of the room they're in, and really hear what they are capable of. Period."

We've talked about this in several versions of the forum and I don't think it can be stressed enough. "Understanding what you are dealing with." It's printed in several JBL publications.

I can't count the number of people who've maligned JBL Studio Monitors over the years. Every single one of them tried to use a 43xx in their home. They were all plug and play types with virtually no concept of the kind of loudspeakers they were dealing with. Their negative experiences were directly related to their attitudes that if they expended the extra effort to spend x amount of dollars on a JBL Studio Monitor then it should just shake right out of the shipping carton and kick major ass. Never mind that many of their rooms utterly sucked in the acoustics department.

It isn't just the 4-ways, the 3-ways and 2-ways like special consideration too. Systems like the 4331 and 4333 can sound very, very good. They can also sound downright awful. It's the user's choice as to how much effort they want to put into the end result. The Studio Monitor should be one of the tools in the bag, not the only tool in the bag.

A beauty post, Giskard. Reminds of the set-ups I've seen/heard of 4-way Studio Monitors, running passive, and plugged into a Receiver... Oh well, when they tire of them, maybe they'll show-up on eBay...

[boputnam]

All gear has "coloration". The amount and influence of that on the acoustic response simply cannot be guessed at.

Scotty Fitlin's having a (justified...) love affair with the Crest amps he's lately been installing at his larger-than-life application. Fine, but, I'm quietly curious on just how much do we really know: How much testing / measurement has been done? Were both the prior set-up and the current one EQ-optimized so that the improvement can really be attributed solely to the Crests? Sure, the ears know, but are the impressions borne-out by giving equal chance to any gear that is trialed? Maybe the Crest have a coloration that is more pleasing to Scotty in his set-up - maybe the same could have been achieved with a better controlling of the existing (now prior...) equipment. I don't know. There has not been much posted on how the application was being "tested"/measured.

I do know that the more I'm able to quantitatively measure and thereby control the signal, the more depth (qualitative pleasure) I get from all my gear, and the more I appreciate the capability that often lies unutilized in stuff I've got. (whew! actually back on topic... )

Having said all that, oldmics has a cotton for Crests, and he more than many of us get's to put gear through the paces, in a variety of settings. So, off I go then...

[Robh3606]

Plug and play???


Rob

[Ian Mackenzie]

I've been thinking about your post - in-particular tonight listening to the fruits of my re-EQ last night.


I loved the 4345's the first time I heard them. Today, I marvel ever-more at their definition, clarity, voicing, and depth of soundstage - characteristics that are optimized by test-gear equal to the quality of the 4345's, and up for the challenge.

Do not under-invest in your test gear, even if only used a few times a year.

'nuff said...

Hey dood, every try getting your ears Waxed, best EQ your ever likey to hear..no Kidding. Shave 1/2 a db off hear and there and WOW.

Hey, on the topic now, Did some interesting observations with John Nebel. We found using the 2235's on the 4343 meant that the levels in the bi amp mode for the woofers extra 1 db sensitivity had to be compensated.

Without allowing for this the mids sounded withdrawn, particularly in straight comparion to the 4435's. With the adjusted sensitivity the voicing of both systems was very similar.

I find similar adjustment, often 1/2 a db on the pads can make or break the whole package, I doubt if the RTA would pick that up.

These types of adjustments take a long time as Robert just commented.

By the way Robert has a very sweet sound on his 2344 / 2123 hyprid.

Ian

[Ken Pachkowsky]

Originally posted by Giskard

It isn't just the 4-ways, the 3-ways and 2-ways like special consideration too. Systems like the 4331 and 4333 can sound very, very good. They can also sound downright awful. It's the user's choice as to how much effort they want to put into the end result. The Studio Monitor should be one of the tools in the bag, not the only tool in the bag.

I spent last Sunday EQ'ing a room for a buddy who had purchased a nice little JBL 3 way system. I convinced him to get a 1/3 ocatve EQ and even I was amazed at the difference it made on those 4313B's.

[4313B]

"Did some interesting observations with John Nebel. We found using the 2235's on the 4343 meant that the levels in the bi amp mode for the woofers extra 1 db sensitivity had to be compensated."

Now that is kind of weird. The 2231 is the more efficient driver but not by a terrible amount. It would be interesting to run a response curve of both drivers side by side to see what they were doing at the crossover frequency. It might be that one has a slight peak or dip that the other lacks. Anyway, if you did the deed and they sound better for it who's to argue.