Advice for Beginners - consider this test from an audio club

[glens]

7 hours ago, Marvel said:

 

Mine [JBL 4311] are in great shape... as far as the cabinets go. I had the original shipping boxes for a good 25 years, so whenever I moved they were well protected and I transported the audio equipment myself and didn't let friends or movers touch them.

 

 

I've got a pair of 4301s from at least 1979 stored away in their original boxes.  There was no foam surrounding the woofer cones last time I looked years ago.  I don't recall what the situation was with the tweeters but I can only image what they're like now.  It's been at least a dozen years since I've seen them.  I really love their (JBL) driver construction from that era.  The woofers have alnico magnets inside an assembly which offers magnetic leakage only at the voice coil gaps.  Paper clips slide ride off the back of the driver but a handful tossed at the cone cling to the inverted dust cap in a circle.  And the rectangular cross-section voice coil wire was wound on edge; they really knew how to build 'em.

 

When I got them I already had a pair of the "home" version (L16?) which had the same drivers but the woofer was allowed to roll off naturally up top instead of having LC components, and the cabinets had slightly different proportions but otherwise constructed the same.  The "home" model had a more pronounced midrange presence, and I preferred the sound of the 4301s, though together they all sounded great.  The cabinets were particle board beautifully veneered on both models with t-nuts for the woofers.  One Saturday after a party at a friend's house I was standing there talking to his mom with a speaker on my shoulder when it slipped off behind me, fell most of 6 feet to the floor, bounced a bit, and the only damage was one of the plastic grill-mounting posts broke.  They were quite heavy for their size.

 

If my 4301s were operable I'd love to have them in service somewhere.  Perhaps I'll hunt down some replacement surround kits...

[glens]

42 minutes ago, Islander said:

 

Right-hand-drive cars have their pedals in the usual orientation, but the shifter is on the centre console, which is to the driver's left, of course.  What can be disorienting at first is having to look up to the left to see the rear view mirror.

 

 

 

Thank you for that.  I'd rather wondered if for safety reasons the accelerator would be toward the inside of the car or something.

 

I'd assume motorcycles are "correct."

[Deang]

Hey Roy - don’t be a weiner. Engage. 

 

I’m doing X11i IEM with Deftones. Wow. 

[Dave A]

Here ya go OD😀

[garyrc]

13 hours ago, glens said:

I never quite made 6'2, just shy and getting shier.  How tall was he in his prime?

 

Well, part of his workout was swinging his leg over parking meters in Hope.

[garyrc]

@ClaudeJ1

 

RE: Fried

 

I have some distortion figures, filched from others.   Some of the below came from Don B. Keele, Jr.  and some from reading Heyser's graphs.       

Speakers                          IM distortion at 105dB (reference level peaks)    Harmonic distortion at 105dB (reference level peaks)
Klipschorn                              1.75%                                                                            0.25%
AR 4-way AR 98RS                 2.7% (1.54XKH)  Audible                                       ~3% (~12XKH) Audible
Fried Studio 4                      10% (5.71XKH) Audible & Annoying                          4% (16XKH) Audible
Platinum Studio 2                  7% (4XKH) Audible and Annoying                           1.9% (7.6XKH) Audible

[Marvel]

4 hours ago, Deang said:

Those are really nice looking. 

 

@Deang    There is a foam ring that goes around the tweeters (missing/rotted away).  Other than that, they are in good shape. No foam or rubber surrounds. I guess the caps need to be replaced... these are simple crossovers.  According to Dennis, may he rest in peace, the mid tends to break up.

 

I only wish they came in a left/right combo. Sadly, all the same. They didn't make pairs until the 4312s

[HiFi Heaven]

105 dB at what FREQUENCY at what DISTANCE?  What was the input POWER requires to achieve 105dB?  What is a "reference level peak"?

Hmmm...  Engineering minds want to know...

[MEH Synergy]

1 hour ago, Dave A said:

Here ya go OD😀

A giant stack of MDF with aoem weird looking speakers in the middle😎?   Awesome. 

[Marvel]

2 minutes ago, Westcoastdrums said:

A giant stack of MDF with aoem weird looking speakers in the middl

 

I don't think Dave is using MDF...

[Islander]

2 hours ago, glens said:

 

Thank you for that.  I'd rather wondered if for safety reasons the accelerator would be toward the inside of the car or something.

 

I'd assume motorcycles are "correct."

 

Motorcycle controls have been standardized since 1975.  Prior to then, there were several different shift patterns, mostly on the left side, from Kawasaki's "all-up" pattern (maybe the best idea), to Yamaha, Suzuki, and Honda's "one down, the rest up", to the British right-side "one up, the rest down", to the rotary "all down, then neutral, then first" which surprised riders who thought the four-speed was a five-speed, but got 1st instead of 5th.  Luckily, that was just on some 100cc bikes.

 

Now, all bikes have the shift on the left, the pattern is "one down, the rest up", the rear brake pedal is on the right, the front brake lever is also on the right, and the clutch is on the left.  Many racing bikes shift "one up, the rest down", which can be confusing if you're running a race bike and a street bike in races the same day.

 

Given all that, why is it that car door handles are all over the place, in a variety of styles?  Having to quickly exit an unfamiliar car could lead to panic in some people if the handle was hard to find.  It could be a real hazard.

[Marvel]

The nice thing about standards is there are so many of them 🙄

[oldtimer]

8 minutes ago, Islander said:

Having to quickly exit an unfamiliar car could lead to panic in some people if the handle was hard to find.  It could be a real hazard.

Riding with strangers?

[Islander]

1 minute ago, oldtimer said:

Riding with strangers?

 

Or just getting a lift from a friend of a friend.  It's not that rare to get into an unfamiliar car, like if your buddy just bought something new and took you for a ride.  And then somehow drove it into a river.

[oldtimer]

Just now, Islander said:

 

Or just getting a lift from a friend of a friend.  It's not that rare to get into an unfamiliar car, like if your buddy just bought something new and took you for a ride.  And then somehow drove it into a river.

Oh I forgot.  That happens all the time.

[Islander]

1 minute ago, oldtimer said:

Oh I forgot.  That happens all the time.

 

I sure hope not!

[Marvel]

3 hours ago, glens said:

If my 4301s were operable I'd love to have them in service somewhere.  Perhaps I'll hunt down some replacement surround kits...

 

The 4311s, as well as the L100s, had drivers with treated paper surrounds. The foam I mentioned was to control reflectio s off the baffle. Beautiful machining on all the parts and great looking veneer. I'm glad I got the walnut and not the studio gray.

 

Bruce

[garyrc]

5 hours ago, HiFi Heaven said:

105 dB at what FREQUENCY at what DISTANCE?  What was the input POWER requires to achieve 105dB?  What is a "reference level peak"?

Hmmm...  Engineering minds want to know...

 

The original articles are in one of several cardboard boxes in the garage.  The summary sheet in the post is all I have at hand.

 

Reference Level Peak, 105 dB through each main speaker, and 115 dB through the subwoofer, in medium zone seats, is the peak SPL (or "full scale," fs) that practically everybody in the film industry uses (Dolby, THX, etc.) as an absolute maximum (many films have peaks lower than that).  My old THX set up folder listed the peaks at 108 dB, but that was in the early '80s.

 

Here is my best recollection for the Khorn and the Fried. 

 

The IM figures for the Klipschorns are for two tones (as usual) put in by Heyser.  He did the Klipschorn for Audio Magazine in 1986, which should be available online.  I believe the two tones were something like 41 Hz and, maybe Middle C (~~ 262 Hz) so they would both be produced by the same driver.  The input power may have been a little less than 4 watts, for a chart reading of about 1.75% IM.  I don't recall the distance, but I think it was something like 3 meters.  At 2.83v (1 watt into 8 Ohms), at 1 meter, anechoic, in an artificial corner in the chamber (1/8 space), the K horn will produce 105 dB.  Keele found that a single Khorn in the reverberant field of a 3,000 cu ft room, R=200,  6.3 watts will produce a continuous average of 105 dB, with peaks 10 dB higher possible (Dope from Hope, January1977, vol 16, No 1).  The distance is not given, but I read somewhere that PWK considered 16 feet "normal listening distance."

 

FWIW, the spec sheets for the Khorn used to list 1% Total Modulation Distortion at 100 dB at 2 feet.  The Cornwall, with it's direct radiating woofer, had 3 times the Total Modulation Distortion at 10 dB lower SPL, same distance!

 

The IM for the Fried Studio IV was done by Heyser (or was it someone else at Audio?), just about the same time.  The uppermost of the two tones was tuning A, since the Fried was a 2-way, with the only crossover above that point.  IIRC, it took about 40 watts to get up to 105 dB, and 10% IM.  I don't know the distance, but I think Audio tried to keep the conditions similar for different speakers back then, so perhaps 3 meters.

 

I don't recall the Harmonic distortion particulars, perhaps because I was less interested in them.

 

Some more organized person here probably has all the data.

[Dave A]

8 hours ago, Marvel said:

 

I don't think Dave is using MDF...

Talking to the guy helping me load last week and he said that they have a stack of 1/4" cover sheets about four foot tall each week from all the skids of Baltic they sell. He said they sell the heck out of it and most goes to speaker cabinets and the thinner material goes into high quality cabinetry. For people who want the very best. They are not the only seller of Baltic in the Nashville area either so who knows how many custom cabinets are built in Music City each and every week.

[Dave A]

8 hours ago, Westcoastdrums said:

weird looking speakers in the middle😎? 

You mean you did not like my cheesy side fill speakers?