4367 Cabinet

[DerekTheGreat]

Hi all,

I have now had the 4367M (M for Modified &#128522 operational for some time and had the chance to develop some quasi anechoic and in the room DSP curves. The room is pretty ok except for a nasty modal at about 30Hz. The curves are nice and smooth from about 30hz to 20k. Even phase looks decent...

...I was happy.

Now that is of course not enough so a few days ago I invited some seasoned JBL friends for a shoot-out. They all have trained ears and excellent systems at home...

I'm deathly afraid of this haha... I love my system, yet there's this itch to share it with others and gain feedback. I expect they would tear it to pieces...

...Kind regards
//Rob

PS thanks to the friends helping out trough the process and especially member “Beatelund” who made this day possible. An understanding wife also helps.

That helps immensely! I wouldn't have the audio system I love so much if not for her. She was right there with me loading and unloading empty cabinets and then stuffing drivers in there as well as sitting in a chair to comment on the adjustments I was making to the sound.

[Robh3606]

Hello Rob

Thanks for posting this. What a line up! Glad you are enjoying your speakers they look great!

Rob

[Mr. Widget]

Hello Rob

Thanks for posting this. What a line up! Glad you are enjoying your speakers they look great!

Rob

+1

Very cool comparisons, thanks for sharing.


Widget

[pos]

They look absolutely stunning, congrats!
Are you going to change your amplifiers?
Have you considered some of the new headphone amps for the compression drivers? 16 ohms is pretty easy to drive for these, and they have plenty of power (well, a few watts, which is plenty for home use in an active system).

[srm51555]

Thanks for the report. Always love to hear about your projects. Only wished you lived closer

[sebackman]

Thank you for the kind words. Its been a fun and humbling journey.

I'm pretty happy for now. I think the odd experience that they kind of "disappears" when playing good material, indicates that we got it at least reasonable right.

Everyone having embarked on a journey outside established trails knows that it is always scary to evaluate the results. Having swapped in large format Be's in my home brew wall mounted M2 wave guide based builds and others, I was reasonable confident that this was they way for me.

The great technicians at JBL certainly know what they are doing, so trying to improve on an excellent design that is very good out of the box is no simple task. Albeit DSP is cheating a little.

I will try to borrow a pair for original 4367's to compare, but they are not very common over here. That would be very interesting.

I will next fall start looking at upgrading the amps from my bellowed Crown CTS, that are getting rather old by now. So far the really good digital amps (Hypex NCx & Nilai and Purifi) are a little too low on power, but bigger ones have been advertised.

POS, I have had some odd experience mixing amps with different gains and sometimes not identical timbre (not better or worse but audible slightly different) so I don't want to mix amps even if it will be crazy overkill to have a high capacity amp to the drivers.

The reasonable small pricing difference compared to the cost of the build and the time invested does not warrant using a mix of amps. If anything it will be two digital stereo amps. Or potentially two SOTA Benchmark AHB2 class AB amps, but they are really toooooo expensive. But very nice. As of now I will keep the two current CTS600 or swap in the two CTS1200 I have in the shop.

Given that no one seem to want the Crown CTS-series for whatever reason, they deliver crazy performance for the price. The topology is not Crown standard but rather similar to the Mark Levinson amps and was indeed constructed by the same individual, from what I have been told directly from Crown. Even the small 600 offers a damping factor of 3000.

For now I will park myself in the couch with a small glass of something and just enjoy.

Recipe and data is of course available to anybody interested here on LHF.

Rock on
//Rob

[mattking52]

Fantastic work, Rob - many kudos to you. Thanks for being willing to share the fruits of your labor as well.

Or potentially two SOTA Benchmark AHB2 class AB amps, but they are really toooooo expensive. But very nice.

I'm running two AHB2 amps in my bi-amped 4344 setup - I can't say enough good things about them. They are expensive, but as I'm sure you know, they often come up on the used market for much more reasonable prices. I bought one used and one new (before their latest price increase), and if I had been a bit more patient, I probably could have found another lightly used silver-faced unit at a lower price.

I have had some odd experience mixing amps with different gains and sometimes not identical timbre (not better or worse but audible slightly different) so I don't want to mix amps even if it will be crazy overkill to have a high capacity amp to the drivers.

I had been mixing amps in bi-amped applications before, with the goal of combining their "best attributes" in the different frequency bands and had weird results just as you mentioned. The gain differences are a solvable problem to an extent, but John Siau from Benchmark mentioned somewhere on the web how the phase response of the differing amps in a multi-amp speaker setup can create issues at the crossover points, which made a lot of sense - I'll have to dig up the link.

For now I will park myself in the couch with a small glass of something and just enjoy.

You deserve it!

[pos]

I have been using an nc400 for the woofer and a THX789 for the compression driver.
This is by far the best amp combo I have ever used and the best sound I was able to get on the M2.
The THX789 has different gain settings on the front so you can leave the volume control at max position measure your gain from there.

I don't think there should be any problem mixing good amps. If you get a different magnitude or phase response around this kind of crossover region then there is a serious problem with one of the amps.

Anyway, throwing in more watts than needed is not a problem either, as long as you don't hear noise through these sensitive compression drivers, or risk too much watt in case of a crossover failure/mistake.

[sebackman]

Hi all,

Pos, I agree that is a very good combination. You can certainly match amps like you are suggesting and I'm probably lazy to want them to match out of the box. You did carefully pick yours, as you do with knowledge, but I have seen/heard combos that did not work well mixing amps.

I guess using the same amps removes one issue from the equation, you don't have to match/check every time you do a change.

I heard that both Hypex and Purifi are launching higher amperage units come this summer. I will wait for that. And for prices to come down. For now the CTS's will do.

Pos, will send you the 4367 curves and would love for you to take a look at them and see if a FIR could be designed. I'm running a BLU160 in stereo use so we should have enough firepower.

Have nice weekend
//Rob

[pos]

Pos, will send you the 4367 curves and would love for you to take a look at them and see if a FIR could be designed. I'm running a BLU160 in stereo use so we should have enough firepower.

Sure, I'm looking forward to that!