Jericho cabinet with Lowther DX4 help

[Wang1]

I recently built a pair of Jericho horns using the attached drg. and fitted new DX4 drivers, the mids and highs are good, but the bass is very much lacking.

I built the same speakers 15 years ago with EX4 drivers and dont remember any issue with lack of bass.

I know very little about theoretical speaker design and based my choice on past experience, and have a few questions:

1. have i made a complete mis-match
2. if so can i improve the bass at all with eq filter or other means
3. what is a tried and tested combination for the DX4


Any other comments welcome.

thanks

 

[planet10]

An old-style front mouth “horn-like” design that probably hornb-loads to something like 100 Hz and below that it is a poor TL.

How wide is this horn? ≈ low frequency cutoff will be 41+41+width+width = wavelenght of low cut-off

With DX4 no bass is expected.

dave

 

[Wang1]

Width is 35mm.

Why no bass with DX4, compared to EX4

Jim

 

[planet10]

So horn loaded to about 90 Hz.

Maybe the EX4 is better in a (bad) TL?

dave

 

[Wang1]

Appreciate your reply but as I said I dont know much about speaker theory.
ls it the enclosure itself that makes the lowther drivers unsuitable if so why is that?
what parameters of the drivers makes them unsuitable
what driver would suit the enclosure and why.
what enclosure would suit the dx4 and provide decent bass ( other than the lowther made enclosures)

would appreciate your help deciding which way to go

cheers

 

[planet10]

It is not a great enclosure. A design that pre-dates modern modelers which have generated better horns.

And while a horn tends to dominate, they need to be specifically designed for a limited range of similar drivers.

@Scottmoose?

dave

 

[Wang1]

Thanks Dave, i appreciate you taking the time to reply to my questions.

I understand that an enclosure needs to match the driver to a certain extent, depending on the end result required which also can be very listener subjective in terms of frequency response.

I have built these now and they sound fine in the mids/highs (they probably would in almost any enclosure) and very listenable for acoustic and vocals but obviously lacking in bass for the reasons you highlight, I am not interested in thumping bass, but at least clearly audible and defined, so it looks like i need different enclosures.

I am a novice when it comes to using design software such as hornresp, (still trying), so i need advise on what enclosure will be suitable for these drivers.

Thanks

 

[Wang1]

I should say the original design was made for the Fostex 208 FE 208 Sigma (attached).

The bass response seems a little better with this driver (or am i completely wrong)

 

[needtubes]

Are your DX4 still fairly new? I found that my PM6a took weeks or months (hard to remember now) of listening on the weekends and some evenings before they opened up. Perhaps they just need some more time to break in properly.

 

[Wang1]

Thanks, they are new, only a week or so, i will give some time before panicking too much.

What boxes are you using?

 

[Freedom666]

Try this filter in line with the driver called LCR filter:

1mh, 0.6mm wire (1,2ohms) and parallel
12 ohms 10 watt and parallel
2.2uF foil cap

That's the one for Fostex sigma but with more ohms on the coil making bass more prominent

 

[Freedom666]

And: put some damping material on the front of the box. Makes audible difference, more bass, less prominent mids.

 

[Wang1]

thanks for the advice, i will try it. i was also thinking of building a voigt pipe for these drivers, they look reasonable to build even for me, will they improve the bass

 

[Wang1]

can you send me a sketch of the filter with values

thanks

 

[Wang1]

ok i see filter now

 

[Freedom666]

That's the filter, you need only R1, c1, L1

I would use only coil with thinner wire, makes more bass

 

[Wang1]

thanks again

 

[planet10]

Are your DX4 still fairly new?

Good point. Break them in generally. Expect changes for at least 100 hours probably many more to settle out.

dave

 

[planet10]

Also have a read of MJK’s Lowther experience… the big rise up top tends to disappear as you go off-axis.

dave

 

[woodo]

@freddi did some simulation in hornresp a while back of one of the Jericho versions
#575 . If one was built, someone might have done some in-room measurements.