Outstanding Performance From "Standard" 6x12" Econowave Guide PH612 H6512 JBL

[Pete B]

The "standard" 6x12" Econowave guide was originally from JBL, discontinued,
Edit: The JBL 6x12" part is available here, not dirt cheap but worth it for better top end:

JBL 338800-001 Replacement Horn Lens

Brand New Genuine JBL Replacement Screw-on Horn Lens #338800-001. Used in JRX100 Series, JRX200 Series, PRX600 Series, Sound Factor Series. Used in the following models: JRX112M, JRX112MI, JRX115, JRX115I, JRX125, JRX212, JRX215, JRX225, SF12M, SF12MI, SF15, SF15I, SF25, PRX612M, PRX615M...

reconingspeakers.com

but then also made by Pyle
(PH612) and now only by Dayton (H6512). People rave about it but if you look at the raw frequency
response with most drivers it is quite bumpy and not very good with depressions around 1 and 3KHz.
When I first heard about this guide I wondered which JBL models it was used in which turned out to be the
JRX212 and some other similar models:
JRX212 | JBL Professional Loudspeakers

I'll get right to the solution found by Mike Chua at Ampslab-Spk. One might think that this guide would work
best with the one JBL designed for it, yes? That was the JBL2414H-C compression driver that is only $55
on Amazon. Here are Mike's unsmoothed measurements, wow unbelievable, almost a textbook perfect curve:
https://ampslab-spk.com/2021/05/03/h6512-jbl-2414-review/



Compare that to measurements with other drivers including the Selenium D220Ti as favored here by many.
Note that all of these drivers have trouble in the 1 and 3KHz range:
https://ampslab-spk.com/2020/06/17/pyle-ph612/

Red curve below is the Selenium D220Ti as a comparison, note the 7 dB drop from 1.5 to 3KHz:



Edit: Polars and test of the H6512 Dayton guide, note that it is stated that this is not an exact copy of the JBL and that the throat diameter is a bit too large:
https://www.mtg-designs.com/tips-tricks-tests/waveguide-shootout/1in-thread-horns/dayton-h6512

Edit: Polars and test of the China Clone of the JBL 6x12", MTG says that this is a faithful copy of the original JBL so this data should also appy to the JBL:

MTG Designs - Clone JBL 338800-001

Manufacturers Info Brand: ---- Model: 338800-001 *Clone* Style: Progressive Transition Coverage (H x V): 90 x 50 Minimum Frequency: ---- Throat: 1" Mounting Type: 1-3/8"-18 TPI Dimensions: 12" W x 6.5" H x 4.25" D

www.mtg-designs.com

This driver should be a significant upgrade for many of the Econowave designs using the 6x12" waveguide
with XO mods as needed.

 

[Pete B]

I'll offer a theory as to why the JBL driver works so well. Here's a picture of the front of
the driver. Note that this is like a dome tweeter with an adaptor to make it screw mount.
The front side of the dome fires straight into the horn. Once the threads are in the dome
is fairly close to the start of the horn:


Here's the back, just like the back of an unchambered dome tweeter:


In contrast all the other drivers are the type where the back side of the dome drives through the pole piece
into the threaded pipe that goes into the guide. This adds about an inch from the dome to the start of the
waveguide:


Threaded side, note there is no dome on this side:

 

[Pete B]

Another theory is that JBL did something different to the phase plug in the dedicated driver.

 

[Guido57]

So is the JBL2414H-C truly a compression driver or just a way to mount a dome onto a horn?

 

[Pete B]

Good question,
I'm not an expert in this area, but from what I've seen, usually the lower end CDs are built as
the JBL is built and the majority of others the other way. But I don't see any reason why this
JBL one is necessarily cheaper or inferior, certainly in this case it is better. Note that this is
not a super high power driver designed to fill a 50K seat stadium but that is not what we are
looking for anyway. It probably should not be crossed lower than 1.5KHz at least on this guide.

I'd say that they're both CDs just different methods. Consider that the back way sees the back
side of the dome and it might be as simple as the phase plug can be better shaped to meet with
that surface but this is complete speculation on my part.

 

[Pete B]

Edit in first post to add link to a review of the Dayton H6512 with polars.

 

[Pete B]

Here's a low cost Eminence that is the front dome type don't think that it performs well in
this application, just another example:




And one from PRV DT175Ph-S about $23 at PE Edit: this has 8-10dB dips around 6K on two
different guides and therefore not going to consider it further.

 

[JRhoBurton]

The "standard" 6x12" Econowave guide was originally from JBL, discontinued but then also made by Pyle
(PH612) and now only by Dayton (H6512). People rave about it but if you look at the raw frequency
response with most drivers it is quite bumpy and not very good with depressions around 1 and 3KHz.
When I first heard about this guide I wondered which JBL models it was used in which turned out to be the
JRX212 and some other similar models:
JRX212 | JBL Professional Loudspeakers

I'll get right to the solution found by Mike Chua at Ampslab-Spk. One might think that this guide would work
best with the one JBL designed for it, yes? That was the JBL2414H-C compression driver that is only $55
on Amazon. Here are Mike's unsmoothed measurements, wow unbelievable, almost a textbook perfect curve:
https://ampslab-spk.com/2021/05/03/h6512-jbl-2414-review/

View attachment 2648485

Compare that to measurements with other drivers including the Selenium D220Ti as favored here by many.
Note that all of these drivers have trouble in the 1 and 3KHz range:
https://ampslab-spk.com/2020/06/17/pyle-ph612/

Red curve below is the Selenium D220Ti as a comparison, note the 7 dB drop from 1.5 to 3KHz:
View attachment 2648487


Edit: Polars and test of the H6512 Dayton guide, note that it is stated that this is no an exact copy of the JBL and that the throat diameter is a bit too large:
https://www.mtg-designs.com/tips-tricks-tests/waveguide-shootout/1in-thread-horns/dayton-h6512

This driver should be a significant upgrade for many of the Econowave designs using the 6x12" waveguide
with XO mods as needed.

My limited experiences messing around with a few driver-waveguide combos led me to think that the response irregularities were properties of the waveguides. Perhaps more messing around is called for.

 

[Pete B]

If you look at many different drivers on the same guide, you'll see a large variation in response there
may be common trends due to for example similar (resonant) distance from the dome to the throat
of the guide. The other important feature of the driver is the fundamental resonance frequency, and
Q which is purely dependent on the driver.
Irregularities above 10KHz and sometimes below are often due to breakup in the dome,
or short distance reflections which is also a characteristic of the driver.

 

[EarlK]

@Pete B

Are you going to buy a pair of these 2414H-C drivers? ( so that you can verify its response characteristics and then design a HiPass for its use in eWave designs ?? )

 

[Pete B]

Well, I think the biggest problem with the LA Econowave is the bass section and
I certainly plan to fix that. I just bought 2 pairs of inexpensive PylePro drivers but
the JBLs are the best way to improve the 6X12" guide so I probably will buy them
in the next few months to do a complete upgrade of the LA Econowave.

Did you notice that mtg-designs says that the Dayton H6512 does not have exactly the
same throat size as the JBL? I only have the Pyle version so not sure which type this
falls into. He also says that the cheap no name clone does not have this problem but
I don't know where to get it. For me, the question is where do I put a bit of bondo or
whatever to correct the throat of the H6512 if I can't buy the clone.

I'd like to buy a blown one first to see what sort of phase plug they're using - anyone
have one?

 

[AudioGMan]

I bought a pair of Pioneer HPM-40(series 2) with the intentions of either just swapping out the cone tweeters with soft domes and getting rid of the supertweeters OR making econowaves out of them. I’ve always liked these Pioneer 10” woofers. Do you think the JBL/Dayton combo would work as a direct swap in to turn the HPM-40s into two ways? The crossover point is 2.5kHz between the woofer and tweeter but the original tweeter is 6ohm. There’s a tweeter pot on HPM-40s to attenuate/boost the high frequencies.

 

[Pete B]

You need CD frequency response compensation, which Zaph has shown can
sometimes be as simple as just a cap. It could be made to work I'm sure but when
spending so much on the waveguide and driver it would be best to have an engineered
crossover.

 

[EarlK]

I bought a pair of Pioneer HPM-40(series 2) with the intentions of either just swapping out the cone tweeters with soft domes and getting rid of the supertweeters OR making econowaves out of them. I’ve always liked these Pioneer 10” woofers. Do you think the JBL/Dayton combo would work as a direct swap in to turn the HPM-40s into two ways? The crossover point is 2.5kHz between the woofer and tweeter but the original tweeter is 6ohm. There’s a tweeter pot on HPM-40s to attenuate/boost the high frequencies.

@AudioGMan

This is the network that JBL used to get a decent HiFi response from the "neo" version of that 2414h driver ( driving a vertically oriented constant coverage horn in the Studio 5xx series of speakers )..



I used this Studio 590's Hi-Pass as inspiration to create something similar ( but with the 2414H-C on the H6512 ).

To get this ( projected ) curve there are 5 coils ( inductors ) in use, which is hardly "Econo" > which may be one reason you dropped into this thread.

Compare to the measured comparison of the Harbeth M-30 to the Studio 530's HF.



I won't be showing the schematic portion of this simulation ( since I want to first see other peoples measured response curves apart from what I used here >> published traces from Michael Chua ).




If 14 passives ( in the HiPass section alone ) makes you shudder then consider a simpler ( to use ) alternative which is a waveguide loaded tweeter.

The Morel CAT378 could fit the bill as would the cheaper ( and getting harder to find ) H26TG45-06 from Peerless ( by Tymphany ) .
Each needs different LC approaches for flat output.

 

[AudioGMan]

@AudioGMan

This is the network that JBL used to get a decent HiFi response from the "neo" version of that 2414h driver ( driving a vertically oriented constant coverage horn in the Studio 5xx series of speakers )..

View attachment 2651275

I used this Studio 590's Hi-Pass as inspiration to create something similar ( but with the 2414H-C on the H6512 ).

To get this ( projected ) curve there are 5 coils ( inductors ) in use, which is hardly "Econo" > which may be one reason you dropped into this thread.

Compare to the measured comparison of the Harbeth M-30 to the Studio 530's HF.

View attachment 2651302

I won't be showing the schematic portion of this simulation ( since I want to first see other peoples measured response curves apart from what I used here >> published traces from Michael Chua ).

View attachment 2651282


If 14 passives ( in the HiPass section alone ) makes you shudder then consider a simpler ( to use ) alternative which is a waveguide loaded tweeter.

The Morel CAT378 could fit the bill as would the cheaper ( and getting harder to find ) H26TG45-06 from Peerless ( by Tymphany ) .
Each needs different LC approaches for flat output.

Okay thanks for all the info. I might just replace the tweeters with Peerless by Tymphany D27TG35-06 silk domes and just disconnect/remove the supertweeters. I like the KISS principle.

 

[Pete B]

@EarlK I'm not sure that I'm following, did you trace FR and impedance curves to make files.
Then use them to design a crossover with the resulting response that you show?

Given that the raw response is so smooth I'm not following why so many parts are required,
did I miss something?
I was just thinking about manually tracing them today in order to try a new XO design. Would
you mind sharing them if you have them?

 

[Pete B]

@AudioGMan Perhaps this but check if Zaph has a review: Peerless by Tymphany BC25SC06-04 1" Textile Dome Tweeter (parts-express.com)

It would be best to start a new thread about mods for your HPM-40 s then it will be easy to find.

 

[AudioGMan]

@AudioGMan Perhaps this but check if Zaph has a review: Peerless by Tymphany BC25SC06-04 1" Textile Dome Tweeter (parts-express.com)

It would be best to start a new thread about mods for your HPM-40 s then it will be easy to find.

I’m sorry Pete I didn’t mean to hijack the thread. As I stated before my original plan with the HPM-40 was to make econowaves out of them and when I read your original post I thought maybe I could use the JBL tweeters/Dayton waveguides with the10” woofers. I guess there’s no easy way of making them work great together without doing something elaborate with the crossover. It’s not a matter of just simply using a 12dB/octave high pass at 2500Hz. I’m realizing that all those components used in the JBL crossovers is to tailor the sound of the compression horn to the waveguide. I’m gonna shut up and continue reading your threads because I’m still learning about how horns work.

 

[Pete B]

Sure, another consideration if you want to use the 6x12" is if you have 12" available
on the baffle.
Where are you located, perhaps there's an AK member near you who could measure
the woofers.

 

[EarlK]

@EarlK I'm not sure that I'm following, did you trace FR and impedance curves to make files.
Then use them to design a crossover with the resulting response that you show?

Given that the raw response is so smooth I'm not following why so many parts are required,
did I miss something?
I was just thinking about manually tracing them today in order to try a new XO design. Would
you mind sharing them if you have them?

@Pete B

Here are some pics that I am willing to share for your use in your own tracing > I strongly suggest using the tracing tool found in VituixCAD2 ( since it adds some necessary phase info ).




It really shouldn't be a surprise that some major effort was needed to recover HF response when there's such a massive 8db drop-off in response ( from 10K to 15K ).

Since a simple parallel RC network can only recover 6 db per octave ( or 3 db per 1/2 octave ) one can readily see the problem/challenge .

Here's a trace of what I could achieve ( with some more heroic effort ) as a simple exercise in table-top flatness. It used 4 coils, though in different placements than JBL's .




Much more optimistically, is a comparison of JBL's own published traces ( for the 2414HC-Waveguide combo ) versus Michaels measurements on the ( now somewhat questionable ) H6512 waveguide.



That red trace ( JBL's published info ) implies there's more HF output available when one uses bona-fide JBL parts ( as Zilch did ).
- BTW, I had to reduce Michaels SPL measurements by 1.5db within XSim to somewhat matchup Mikes levels to those of JBL's ( when using the same published JRX225 network ) .

Net//net here is there is still room for some optimise that a simpler network ( using bonafide JBL parts ) is doable.



PS; JRX225 network & published response;