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Discussion Starter #1
I've searched this forum and I finally went in this forum section. Because I dont talk about subs but for the best use of what I get on hands. I have a pair of 15" JBL K-145, 2420 mid-high compression drivers, McCaully 9" horns(similar to the JBL 2391 accoustic lens) or the standard 20" (2390)folded lens.

I also have (center channel?) a 15" Altec 604E 8HPLN that could be used. I already have passive X-Overs but I would probably go for active X-Over(Berrhinger)

Have a modified Crown DC-300 (210 Watts/Ch/8Ohms)and a D-150 amp(75WCh/8Ohms).

I know that this question cannot represent a great deal of enthusiasm but who knows. Theese things are collecting dust. I would like to be an environnemental friendly guy:boxer:
 

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Hi Serge and welcome to the Shack... :T

Are you looking to build subs from these or full range speakers.... or is that what you want to know, what others would recommend?

I am thinking this might be a design challenge to piece these together.
 

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Discussion Starter #3
Hi Sonnie

I just have those speakers (2 way) that I used for my keyboard setup (long time ago):duh:

They aleady are in a plywood bass reflex enclosures(plans from JBL) but the match between them are far from optimal but I was thinking of an efficient loudspeaker playback system and the most hi-fi possible, I've seen some studio monitors(westlake) that used the 2420 as a hi-mid/tweeter mounted directly on a round plate without horn that sounded quite good, that was matched with a JBL2440 mid mounted on a wood horn and 2X15 JBL woofers(don't remember model) that were going quite low(not as low as any sub) maybe around solid 40Hz. I don't have subs for the moment but for musical(60%) and home cinema(40%) I would endure without subs for now.

My point is to integrate (phase wise and XOver slopes, etc) those 2 drivers. The 2420 is quite efficient(around 110db/watt/meter) and the woofer is around 97db. Electronic xover is the answer, I know but what kind of enclosure/xover type would make it the most for my money?

Finally I have a 604E 8Hpln(high power version of the Altec 604E) that I could use for a "center channel" in a home cinema. I know that this driver sounds harh with original passive xover but I'd like to hear it sounding "sweeter" because a point source(real coaxial) should be a good thing for center chanel. I don't have separate specs for this speaker, being that there is an efficient woofer(around 100db/w/meter) and moore for the mig/high driver(horn loaded).

I wouldn't like to throw away these mamooths:spend:

Going to the lowest possible freq. sans super big boxes would be preferable.:doh:

Finally a cost effective system, I already have a Crown DC-300 and Crown DC-150 for power amps.

Thanks for the reply:jiggy:
 

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Going to the lowest possible freq. sans super big boxes would be preferable
Since the JBL K-145 is a musical instrument speaker with no published T/S parameters, I can only suggest to build the box to the recommended volume suggested by JBL. Be aware that it probably won't be the optimum size for what you are trying to do. Your only other option is to test the speaker to see what the parameters are.
 

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Discussion Starter #5
Here is what I found for the k-145(limited specs):

Brand JBL
Model K145
Description Cast frame, paper cone and textile surround
Range / type Woofer
Typical use Undetermined
Nom. diamerer [inch] 15
Vas [Liters] 243,5
Qts 0,29
Qes 0,3
Qms 6
Fs [Hz] 35
Sensitivity [dB] 97
Max Power [W] 150
Power definition Thermally-limited maximum electrical input power
Lower freq [Hz]
Upper freq [Hz]
Rec. Filter freq [Hz]
xmax [mm] 5,08
Moving mass [g] 75
Disp area [m2] 0,079
Disp Vol [cm3]
xdamage [mm]
Air gap [mm]
Coil height [mm]
Coil diameter [mm]
Cms [mm/N]
Rms [N*s/m]
Magnet weight [gr]
Magnet height [mm]
Magnet diameter [mm]
Magnet material -
Re [ohm] 8,8
Z [ohm] 16
L [mH] 2,2
Bl [Tm] 21,7
Magnetic flux [Wb]
Flux density [T] 0,9
Outer diam. [mm]
Bolt circle [mm]
Nr of bolts [Nr]
Cutout [mm]
Weight [Kg]
Height [mm]
Depth [mm]
Driver volume [Liters]
Frequency SPL / Z
Date reviewed 2004-02-02
Date added 2004-02-02


And for the Altec 604-8HPLN that is a higher power than the 604-8H but the closest from the database:

Brand Altec Lansing
Model 604-8H
Description Cast frame, paper cone and textile surround
Range / type Woofer
Manufacturer Pre -1998 Altec Lansing
Production status Discontinued
Nom. diamerer [inch] 15
Vas [Liters] 558,8
Qts 0,2694
Qes 0,28
Qms 7,1
Fs [Hz] 28,1
Sensitivity [dB] 98
Max Power [W] 100
Power definition
Lower freq [Hz]
Upper freq [Hz]
Rec. Filter freq [Hz]
xmax [mm] 3,8
Moving mass [g] 63,66
Disp area [m2] 0,089
Disp Vol [cm3]
xdamage [mm]
Air gap [mm]
Coil height [mm]
Coil diameter [mm]
Cms [mm/N]
Rms [N*s/m]
Magnet weight [gr]
Magnet height [mm]
Magnet diameter [mm]
Magnet material -
Re [ohm] 6,5
Z [ohm]
L [mH] 0,001
Bl [Tm] 16,153
Magnetic flux [Wb]
Flux density [T]
Outer diam. [mm]
Bolt circle [mm]
Nr of bolts [Nr]
Cutout [mm]
Weight [Kg]
Height [mm]
Depth [mm]
Driver volume [Liters]
Frequency SPL / Z
Date reviewed 2003-08-28
Date added 2003-08-28
:coocoo:
 

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Discussion Starter #7
Unfortunately, modeling either of those doesn't look so good below about 35-40Hz or so. Anything lower and you'll probably end up with loads of distortion if the driver survived its excursion limits.

Here are the two WinISD files if you would like to tinker with them for best performance.

View attachment 10824

View attachment 10825
Oups! I cannot read those files, I have a Mac:sad:

I'll find someone who has it:nerd:

For shure I don't expect to go really lower than 40Hz and I like the dynamics and the "tone" that theese woofers provide.:T

I know I need subs for later:yes:
 

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Discussion Starter #9
Thanks Sonnie

I have a PC that my son uses.

I'll try to find that software.

By the way is it a freeware or it is part from a Window bundle?

Thanks again
 

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Discussion Starter #14
Thanks everybody

I know I have some homework to do but you're very kind to give some help.

That is this forum from where I had the most helpful hints.

Long live and congrats to this forum:T
 

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You'd be best served by trying to only extend the bass response to 50hz or maybe even 60hz probably in a bass reflex alignment and then adding a sub later on. Try some Winisd modeling and shoot for a response that gently slopes off a bit towards the low end cut off.

Do you have any measurement equipment? Microphone, spl meter, soundcard, etc? The best way is to measure the drivers using something like HolmImpulse(freeware) or similar and find out what they've got going on. Then you can start playing with crossover and level settings of the woofers and tweeters to get them to blend together. Are there published manufacturer response curves for any of your drivers? That would be something to start with at least.
 

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Discussion Starter #16
You'd be best served by trying to only extend the bass response to 50hz or maybe even 60hz probably in a bass reflex alignment and then adding a sub later on. Try some Winisd modeling and shoot for a response that gently slopes off a bit towards the low end cut off.

Do you have any measurement equipment? Microphone, spl meter, soundcard, etc? The best way is to measure the drivers using something like HolmImpulse(freeware) or similar and find out what they've got going on. Then you can start playing with crossover and level settings of the woofers and tweeters to get them to blend together. Are there published manufacturer response curves for any of your drivers? That would be something to start with at least.
Thanks for the tip about tuning Ricci.

I'll get mic(berhinger) and I have the audio interface(phantom power too)

I've heard about econowave waveguides that could sound smoother compared to the horn I have. I would prefer not to cross higher than 1,5Khz,

Someboby could guide me to wich one of the ewave to use with the JBL 2420 driver(bolt on) ?
 

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I've searched this forum and I finally went in this forum section. Because I dont talk about subs but for the best use of what I get on hands. I have a pair of 15" JBL K-145, 2420 mid-high compression drivers, McCaully 9" horns(similar to the JBL 2391 accoustic lens) or the standard 20" (2390)folded lens.
The K145 is a very decent driver. It's an older design from before JBL did further research into motor design and improved them - it's sort of an old school 2225. The inductance is a bit high for my tastes (you can easily see the roll off in the attached FR simulation) to make it a two way, but it might be able to be done, you'll need to measure and check.

Similarly the 2420 is a good older driver design still well regarded. The 2390 horns I'm not so fond of. A better alternative would be one of the QSC 152 or larger JBL PT waveguides, which are quite cheap as spare parts (if interested, I'll add some links later).

As you have a DCX, 6th order ported is a possibility. The K145 section would be 90L net, tuned to 35Hz, with 1 4" port 5.7" long. Though the driver is only rated at 150W, it will take 250W peaks before just hitting Xmax. All the attachments are with 150W input.

Personally, I'd find another amp and some 2123, 2012 or AE TD10M and make it a 3 way.

FYI, the T/S for all the JBL cone drivers can be found here.

I also have (center channel?) a 15" Altec 604E 8HPLN that could be used. I already have passive X-Overs but I would probably go for active X-Over(Berrhinger)
That would work. It's a good driver, but it may sound different enough to the mains to be noticeable. Or not. Costs some time to build it and find out, but not much more.

Have a modified Crown DC-300 (210 Watts/Ch/8Ohms)and a D-150 amp(75WCh/8Ohms).

I know that this question cannot represent a great deal of enthusiasm but who knows. Theese things are collecting dust. I would like to be an environnemental friendly guy:boxer:
I agree, use them. They have the potential to be a very good system.

I'm off to bed (nearly 2am), so if you want more info, I'll do it tomorrow.
 

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I had the same dilemma with my old (but good) Altec Voice of Theaters and AR2As,, my main set up used was Def Tec with 7002 as fronts and a CLR2500 center with BP-2X sides,, wanted to expand to a 7.1 and after I purchased my Marantz SR9600 I used the AR2s for the sides and moved the BP-2X to the backs,, after reading the Marantz book I find it will support dual fronts so I now use the Altec Voice of Theaters with the Def Tec 7002s for my front L & R,, sounds like I am setting inside the action,, the AR2As for the sides are also amazing,, when there is bass to those channels they can really pump it through and the mids and highs are crystal clear,,

I was going to consider reworking the Altecs with a different woofer and change the cabinet for more bass as they drop off fairly fast in the mid 30hz,, had others suggest leaving them alone as they are such good speakers and add a sub for that really low bass, why mess up a good speaker,, even though Def Tec says the 7002 are good to 30hz level with the internal amp they still could not offer the impact of good LFE,,

so I left my two sets of aged but good speakers alone and added a SVS pb 13 ultra to handle the bass I was seeking,,

Derry
 

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Discussion Starter #19
As you have a DCX, 6th order ported is a possibility. The K145 section would be 90L net, tuned to 35Hz, with 1 4" port 5.7" long. Though the driver is only rated at 150W, it will take 250W peaks before just hitting Xmax. All the attachments are with 150W input.

Personally, I'd find another amp and some 2123, 2012 or AE TD10M and make it a 3 way.
Thanks A9X for all your contributions!

Would I gain in benefit to have bigger box? I have room for 150L net

Scenario 1:

The bigger JBL waveguide could give better dispersion at lower x-over point around 900Hz to 1KHz? If so I would be interested to get them. The 2420 driver itself can be crossed at low as 800Hz(12db/oct).
This gives me more chances to stay in a two-way system because I don't know the K-145 dispersions carracteristics at 1KHz. The higher I crossover the narrower is the dispersion.

Scenario 2:

The smaller JBL waveguide to crossover higher, around 2K to 3K and using the 2123 as low-mid/mid so the ten inches wil have it's own (sealed) enclosure and how big it will depend at wich low cut freq. being decided, and all of this will have to match the dispersions of all components. But how costs a pair of 2123? Having room to put isolated chamber for the 2123 is easily possible taking in account that you give me 90L for the K145.

So much questions:scratch:
 

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Thanks A9X for all your contributions!
My pleasure. When I saw the components, it reminded me of my sides and rears that I am building. Later today I may have the drawings finalised, but the configuration is set; JBL2225 in 55L net, ported at 40Hz, 6th order, crossing to a 2123 at 300Hz and to an 18Sound ND1090 and B&C DE250 on JBL PT waveguides at about 1k8.

Would I gain in benefit to have bigger box? I have room for 150L net
Assuming the 150L doesn't include the volume taken by the driver ports and bracing, you get something like this (see attachments for X and PAS).



Note there are 2 x 4" ports 7.5" long, and you will need a HPF to protect from over excursion with movies at high level if you are not using subs. The 6th order I showed earlier already has the LPF as that's part of it's design.

If you are going to use subs and an 80Hz xover to them, sealed with a whiff of EQ at the bottom would give an F3 of 80Hz (no EQ=90Hz) in any size from 41L to 120L.

For non sub use, them either ported would be best.

Scenario 1:

The bigger JBL waveguide could give better dispersion at lower x-over point around 900Hz to 1KHz? If so I would be interested to get them. The 2420 driver itself can be crossed at low as 800Hz(12db/oct).
This gives me more chances to stay in a two-way system because I don't know the K-145 dispersions carracteristics at 1KHz. The higher I crossover the narrower is the dispersion.
Those old horns have their fanbase, but they sound like horns to me, at least the couple I have heard. There has been 40 years of development here and later flares are generally better in my opinion.

Scenario 2:

The smaller JBL waveguide to crossover higher, around 2K to 3K and using the 2123 as low-mid/mid so the ten inches wil have it's own (sealed) enclosure and how big it will depend at wich low cut freq. being decided, and all of this will have to match the dispersions of all components. But how costs a pair of 2123? Having room to put isolated chamber for the 2123 is easily possible taking in account that you give me 90L for the K145.
2123 can be found quite cheaply if you're patient. Jammin Jersey usually has some but only one ATM. Other options are the AE TD10M which is a better driver (I have 4 ea, 2123 and 10M) and I'd go with this at $244/driver rather than $200/ea for a secondhand 2123. The B&C 8NDL51 is also another fine driver and much cheaper (datasheet at bottom of page).

A mid would need to go into a closed back chamber, but most here work nicely in <10L net, so they don't take a lot of space.

WRT dispersion, you ideally want the MF and HF to have the same dispersion at xover - not hard and there's some wiggle room.

So much questions:scratch:
You don't ask, you don't get answers.
 

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