How well would the 416z and the 604c combine?

[LICORNE]

I'M COMPARING AN ALTEC 416 WITH AN ALTEC 3184 SUBWOOFER.

[GM]

Greets!

Bob, I understand where you're coming from, but having built numerous low Fb cabs using low Xmax, low Fs HE drivers (including the 416), I disagree that they can't make sufficient bass in a typical hi-fi app. The trade-off is a much larger box size compared to a low eff./Vas, higher Qts 'sub' driver. Then there's the issue of SQ. If XO'd low enough then it's not really an issue due to our hearing acuity rolling off with decreasing frequency, but even 80 Hz isn't low enough for many folks to hear the difference if the various opinions expressed on numerous forums has any validity WRT impulse response, etc.. 40-60 Hz is the range most often quoted for those who have experimented, including me, with the room's effect/XO slope controlling the point.

For XO points greater than 80-100 Hz and/or XO slopes less than 4th order, few 'sub' drivers are suitable and they tend to need larger cabs and cost considerably more, so in these apps the Altecs are viable alternatives. Also, due to the increased Vb, cone flex and its various attendant distortions isn't an issue, which isn't the case in the acoustically small Vbs of the 6041, Iconic/Valencia, etc. alignments. Obviously, for 64 ft pipe organ or HT apps, either more drivers or high mechanical/electrical power sub drivers driven with kilowatts of power is required.

WRT isolating the midbass and sub systems, it really depends on the performance goals as to whether this is warranted, or even desired. for an acoustically small, high Fb alignment such as the 6041 or when radically different drivers are paired up, then for sure they must be isolated. Even in some cases such as high power PA apps where the drivers are the same make/model, it's required to ensure that any spec mismatches does't make one of them a current 'hog', rendering the other one little more than an active passive radiator until the 'hog' begins rolling off due to thermal power compression or worse, burns up.

In a typical hi-fi app where a low Fb is desirable and size isn't a major issue, then combining the same or disparate drivers in a common cab can perform quite well SPL/SQ wise with no need for another XO point. For same/same, just double the Vb of a single driver's chosen alignment, and for disparate drivers, average their specs and design based on these. For this combo the 'sub' ideally needs a lower Fs, higher Qts, and same/higher Vas and the system tuned to at least the 'sub' driver's Fs. Other than size, the main trade-off is that one or both drivers may run out of Xmax in the BW above Fb, but at the levels these are capable of it's not a problem in typical hi-fi apps.

WRT to your other remarks, yeah, time marches on and you can only tweak outdated technology so much before it becomes irrevocably obsolete, especially when it was known to be a highly compromised design from the get-go, a point I periodically make and get 'slapped up side the head for' by the 'blind' faithful.

Anyway, WRT to Theo's system, the 416Z's I'm familiar with are optimized for the Valencia (much lower Vas than other models), so I agree that it should be isolated in its own cab for theoretically best performance, particularly in a cab as small as the 6041, though it can work well in a large cab tuned to the lowest driver Fs using the averaging method if some vent tuning via damping is done.

GM

[joyspring]

GM:

Larger boxes with low Fb and tuning for HE low-Xmax low-Fs low-Qts drivers was what I meant by `coaxing' a 30 hz F3... I'm glad someone on this forum sussed this out ;-) However, I still believe in maximum headroom, even in the extreme LF. Have a listen to some of the new AIX 24-bit/96 kHz DVD-As or Delos classical SACDs that were digitally recorded (instead of the 30 ips analogue that loses everything under 40 hz).

I recommend separating sub and MF/HF enclosures so the subs can be placed independently of L/C/R/LS/RS as this is simplest means of mitigating room modes at the preferred listening position.

Using a sealed enclosure for the 604Cs will offer a lot more latitude for enclosure size. 3 - 6 ft^3 will yield between a critically-damped and maximally-flat response and 50-70 hz F3, not that it's all too critical with a steep high-pass filter and 80 hz crossover point.

A nifty retro period-correct idea would be a facsimile of the Altec 612 or 614 enclosure:

Altec Utility cabinets front

Altec Utility cabinets rear

A *lot* more period-correct for a 604C than the Japanese 6041 system.

This will offer Theophile the most flexible room tuning with whatever sub driver he chooses.

Allowing the disparate drivers to `talk' in the same vented enclosure introduces far too many variables when initially designing and tuning the system IMHO. Also, one recone could markedly alter both LF and MF system performance and require total system retuning.

Regarding sound quality and sound localisation for subs crossed over at or below 80 hz with a fourth-order or higher crossover: it is my opinion that these criteria suffice. If one notes sonic issues or can localise the sub, harmonic or asymmetric distortion would be the first culprit to investigate..

BobR

[theophile]

Interesting discussion guys!
I definitely don't intend using the 416 in the subwoofer regions.Down to 40Hz would be sufficient.As I stated my intention was to utilise the drivers in the frequency range where they are reputed to excel.Nothing more.
The photo of the speakers in the Japanese wood panelled recording studio fits to a tee the concept I had in my head of the application I wanted.I just needed to know whether it was a feasible concept,and it obviously is!
I can't undertake this project immediately,but when I get the resources,I will.
If I feel the need for subwoofer frequencies,I'll buy a subwoofer.
I definitely appreciate everyones input on this thread,and if anyone has anything further to add as to port dimensions or other useful pointers which could make this idea a reality,I'd be happy to take note.
Thank you all.

[LICORNE]

Hi
Concerning the 604 1 Japanese studio Monitor,the 2 speakers 416 and 6048h are seperated completely inside, They both have their own duct port.

It's a good concept .If it was not for it's heigt
cabinet dimension .I would probably build a set.

[Lifewithmusic]

I actually tried to build some of these 604/416 cabinets about 25 years ago. I still have them. I only used the cross over for the 604-8a. Never built a proper crossover to the 416. Right now I have 604 in the upper hole and an Altec 3156 woofer in the bottom.

Does anyone know what separate tweeter was used in the Japanese monitor model? What were the crossover specks to it, and did the Mantry horn run all way without being sloped off?

Actually I just found this board last night and so am really new here. Seems like a great site. I hope I don't ask any dumb questions.

I suspect that there are ways to greatly improve the stock 604 crossover, and probably to update it given that mine is 24 years old, or so. Can anyone direct me to an appropriate link for that information?

[LICORNE]

Hi

You asked oes anyone know what separate tweeter was used in the Japanese monitor model? What were the crossover specks to it, and did the Mantry horn run all way without being sloped off?

The XO are 350,1500,8000,. The tweeter says 6041-ST. Looks like dome tweeter for ALTEC CEILING DUPLEX at ALTEC LANSING PRO.The Mantaray horn stops at 8000.

I'l have a Japanese read the tech brochure eventually.

.............................................

[Lifewithmusic]

Many thanks.

[LICORNE]

It was probably the MR902 with out the mantaray horn.

http://www.lansingheritage.org/image...pro/page05.jpg

.............................................

[GM]

Greets!

Don't know what it is, but the pics I've seen showed a 'bullet' phase plug loaded horn similar to some Foster/Fostex units, and judging from the mounting adapter plate it's a thread mount, so like no Altec I've seen.

GM