Specification of Lancer 44

[mda3313]

Any information please? especially the frequency range and the sensitivity.

[yggdrasil]

http://www.lansingheritage.org/html/jbl/specs/home-speakers/1967-l44-l47.htm

[mda3313]

Thanks. But I want more details. There is no sensitivity or frequency information there.

[Earl K]

Here;

- Download this pdf from JBL Pro (http://www.jblpro.com/pub/obsolete/le8t.pdf) to get the info that you're after.

- You're alnico versions are close enough to these specs to make the differences insignificant.

- Here's a link to the index for other obsolete parts. (http://www.jblpro.com/pub/obsolete/)

- Did you build an L-Pad as Giskard suggested to help balance your le175 with those le8t(s) in your custom project ?

:o:

[mda3313]

No, not yet. I am still trying to balance the sound with N1200 only with different position of the 175. From the spec, even setting the N1200 to the min. level, the 175 is still 10db louder than the LE8T. However, in my room, the sound level between 2 drivers is probably less than the measurement. This is the reason why I am asking for the spec. of the speakers but not the drivers.

[GordonW]

Are you using the Lancer 44s as a "full-range" bass driver (ie, as the only LF driver in the system), or is there a subwoofer driver?

If there's a subwoofer, one suggestion might be to remove the PR8, and install a SECOND LE8 into the cabinet, making it into a dual-driver midbass/midrange array. It will no longer go down below about 50-60 Hz (due to the loss of the passive radiator bass reinforcement), but the overall output level of the LE8 "array" (ie, the two of them together in one cabinet), should be in the order of about 6 dB louder than one single driver.

Dunno if this works with your plans, but I thought it would be good to at least mention the idea...

Regards,
Gordon.

[Earl K]

No, not yet. I am still trying to balance the sound with N1200 only with different position of the 175.

- That makes no sense to me . One reason Giskard suggested adding an extra LPad into that Horn circuit would be to help you balance the horn to the woofer(s) .

- Do you know how to create a 6 db pad out of 2 resistors ? Depending on your country of location , total cost for two channels is going to be $ 1 to $ 4.00 for standard 10watt wirewounds . Wire it up after the Hipass portion of the crossover.

- Did you end up running 2 le8t woofs per channel in those "L-44" boxes ( as per your other thread ) ?
- If so , I'm hoping that you realize that you've dropped the Low Frequency load impedance from @ 8 ohms down to around 4 ohms . This means that the inductor & capacitor ( LC ) components in the woofer leg of the crossover are now the incorrect values to maintain a 1200 hz crossover point. .

- I think I'd sell those N1200(s) and buildup from scratch, some custom 2-way networks if you want to use two woofers per box .
- The two woofers per box idea , does have some merit ( IMO ).

FWIW : here's a link to the N1200 network schematic (http://www.jblproservice.com/navigation/Network%20Schematics.html) ( It's a 1 meg file for those on dialup ) .

:cheers:

[mda3313]

:jawdrop: No, I have not tried the 2 LE8T in the L44 yet.

For me, I think it is possible to balance the sound levlel of 175 and LE8T by repositioning the 175. I thought I have read in the past that the sound level of the driver would drop about 3db when moving back one inch. In fact I have already tested with the sound level meter and found that the sound level of the LE8T and 175 are about the same if I move the 175 further back than the LE8T by 3 to 4 inches (providing that the N1200 is set at the min. level).

Correct me please if my concept is fundamental wrong.

Lawrence

[Earl K]

Correct me please if my concept is fundamental wrong.

- Okay, your concept is wrong .
- Your understanding ( about some of the most fundamental properties of sound propagation ) is either off base or being misapplied .


I thought I have read in the past that the sound level of the driver would drop about 3db when moving back one inch.

- You should retrace your steps , find the article that you read and then reread it . Ask questions about what that information means and how to best apply it.


- Also, in the meantime, build some 4 - 6 db pads out of some resistors to help correct your Hi-Lo balance problem . ;)

:cheers:

[GordonW]

It would be possible, if desired, to modify an N1200 for 4 ohm LF operation. Attached are the original N1200 schematic, plus the modified version. Note that in the lowpass (LF) section of the modified network, all inductors and resistors are HALVED in value, and all capacitors are DOUBLED in value. This will do a "quick-and-dirty" conversion of the network, for a bass driver system of half the impedence (ie, 4 ohms instead of 8).

[GordonW]

However, I agree with Earl K... a better solution, would be to construct a WHOLE NEW network. Toward that end, here is a suggestion, of a topology and some initial component values to try. These should mate up with the drivers DCR, inductance and such, pretty well:

[mda3313]

Thanks all the advise and schematic etc. from the members.

Now I have put a L-pad between the N1200 and 175. the sound is obviously smoother but lost a bit of transparant and excitment. At the present L-pad position, it measures at about 3 ohms (about -3db of 175).

One further question to ask as the rebuilt of the crossovers or the use of electronic crossovers is not considered at the moment due to my poor knowledge of DIY skill:-

1) From the local web-site, apart from the idea of using elecronic crossovers and rebuilt crossovers, there are suggestions by using L-pad or resistors between N1200 and 175 (equal to some suggestions from the members here). However, there were arguments whether the use of L-pad or resistors would do the least damage of the sound. Terms like phase problems and distortions were mentioned in the debates. Please share your view.

Furthermore lease advise me the differences and sound between 16 ohm and 8 ohm version of 175 because the 16 ohm would cost more. My pair of 175 has the serial no. of 18000 (8 ohm), any idea of the year of manufacture?

Many thanks. :D

[Earl K]

Furthermore lease advise me the differences and sound between 16 ohm and 8 ohm version of 175 because the 16 ohm would cost more. My pair of 175 has the serial no. of 18000 (8 ohm), any idea of the year of manufacture?

- No separate versions of the 8 ohm or 16 ohm le175 driver ever existed.

- They are all the same impedance ( 10 to 12 ohms ).

- JBL just changed the way they labelled impedance / accordingly for marketing reasons ( either for the Pro user or for the DIY user ) .

[mda3313]

Same story as 8 ohm / 16 ohm N1200?

[Earl K]

Now I have put a L-pad between the N1200 and 175. the sound is obviously smoother but lost a bit of transparant and excitment.

- I've heard that highly inductive resistors can effect the sound this way. Personally, I'm uncertain if I can "hear" resistors . I use 5 or 10 watt no-name wirewounds. Now, I know I can "hear" the different nuances from capacitors / but that is an ear-training sort of thing ( it helps being a non-practising musician ).

- I would build a 3 db pad using the best 10 watt resistors you can afford ( if you think you can "hear" resistors ). Find an online calculator for pads and enter in the appropriate numbers. For "tweeter" impedance use values of 10 to 12 ohms ( whatever ends up giving nice resistor values ) .
- Don't bother over-thinking this impedance thing ( JBL certainly didn't in the 1960s ).

FWIW :

(A) at 8 ohms ( for a 3db pad ) my calculator gives values of ;

R1 = 2.336 ohms ( make it 2.3 or 2.4 ohms )
R2 = 19.39 ohms ( make it 19 or 20 ohms )


(B) at 10 ohms ( for a 3db pad ) my calculator gives values of ;

R1 = 2.921 ohms ( make it 3 ohms )
R2 = 24.24 ohms ( make it 24 ohms )

(C) at 12 ohms ( for a 3db pad ) my calculator gives values of ;

R1 = 3.505 ohms ( make it 3.5 ohms )
R2 = 29.09 ohms ( make it 30 ohms )

(D) at 16 ohms ( for a 3db pad ) my calculator gives values of ;

R1 = 4.673 ohms ( make it 4.5 or 4.7 ohms )
R2 = 38.78 ohms ( I'd make it 39 ohms )

- "R1" is the resistor that is in series ( inline ) with the driver , and is placed in the circuit before "R2".
- "R2" is the resistor that is parallel ( shunting across ) the driver, and is located in the circuit immediately after "R2".

:p

[mda3313]

hello Earl K

Thanks for your valuable input. As I am not a DIYer, please correct me if I am wrong.

1) as 175 speaker terminals are spring loaded, stick one lead of the R1 resistor in the positive terminal and the other lead connected to the + speaker wire ,for the R2 resistor stick one lead into positive terminal and the other lead into the negative treminal. the negative speaker wire should also be in the 175 - terminal.

Am I right?

Also where can I find the web-site helping calculation those R1 /R2 value?

Thanks.

[Earl K]

Thanks for your valuable input. As I am not a DIYer, please correct me if I am wrong.

1) as 175 speaker terminals are spring loaded, stick one lead of the R1 resistor in the positive terminal and the other lead connected to the + speaker wire ,for the R2 resistor stick one lead into positive terminal and the other lead into the negative treminal. the negative speaker wire should also be in the 175 - terminal.

Am I right?

- Yes you're correct .


Also where can I find the web-site helping calculation those R1 /R2 value?

I don't know off the top of my head / you'll need to Google search on your own, for that service .