JBL 4530 Replica

[JRjunior]

I've build some new JBL 4530 replicas with Precision Devices PD154. Deep loud bass coming out. Have only left to sand and color it down.

Here some pics.

 

[Richard Ellis]

'Junior'
Nice...really nice.. Your system is kinda like what I'm looking for.Ultra High Db levels...as I am making a tube amp with only 2.2 Watts worth of output power.
Do you have some specifics we can all mull over???? Have you done some Qtc calculations?? SPLs' ???
I believe I recognize that HF driver from the Partsexpress listings....The 106 Db 'tweeter' in the "pro-sound" sections.

____________________________________________________Rick...

 

[djk]

"Deep loud bass"

Show me the measurements.

No deep bass out of a 4530, it's too short.

 

[JRjunior]

It's not 20 hz.. They are usable from 35Hz placed at wall @ 36 Hz is whole house shaking. PD's154 has a nice Xmax (7.7mm).

Here's predicted response.

 

[JRjunior]

Sure it's not 20Hz.. indeed I have no music with such low notes.
Usable from 35Hz placed at wall @ 36Hz whole house rattles.

Here's predicted response.

 

[JRjunior]

Under the horn path lenght, horn works like a bassreflex/transmission line.

 

[bjorno]

..No deep bass out of a 4530, it's too short..

Agree, See the quick ‘clone’ simulation= Picture (1) and the picture (2) where the PD.154 driver is used too for bass but IMO a sub bas should have at least similar performance to the in picture shown Eminence-Definimax-18LF driver.

b

 

[bjorno]

Hi all,

Sorry, I posted pictures with bad PD.154 T/S data,Ill be back soon with new pictures.

b

 

[JRjunior]

@bjorno; not only PD154 data, your other calculations are way off too.. (VTC, ATC, S1, horn lenght..!?)

 

[bjorno]

@bjorno; not only PD154 data, your other calculations are way off too.. (VTC, ATC, S1, horn lenght..!?)

Hi,

Here are the revised pictures (correcting the T/S data):..

My ‘bad’ PD.154 data was consistent with the larger than in reality Mms that only scaled down the SPL not the performance more than marginally.

I don’t think my simulations are way off at all. You’ve simulated a ND but this particular speaker is practically IMO, an OD Horn.

I choose the OD template because the picture I submitted of the original depicts an offset driver and not uniquely a separate compliance chamber.

The first smallest CSA radius at the very first bend is about 10 cm i.e. the CSA would be 10 x 56.5 = 565 cm but starts shrinking conically from the CSA=16.8 x 56.5= 898 cm^3: (21.6-3.8-1.9 = 16.8) cm).

The more sections and CSA’s the (OD) horn uses, is IMO more closer to the original than a perfect exp expansion but you may have followed your own simulation very closely but that’s completely another issue.

b

 

[JRjunior]

Did you used the tool option "combined response" from the cone and the horn mouth ? It sims like not. The dip in SPL in reality appears between 150-160Hz like in my simulation and not at 400 hz. Compression chamber has a 34 liter and not 1,69 liter. 4530 it's a rear loaded horn.