New Custom Cabinets for LE14H-3, 2452H-SL and PT-F95HF

[Duffinator]

Hi all, it's been a while but I'm about ready to redo my custom ZD-007 speakers that Zilch help be make back in 2007. Some of you may remember these from the eWave threads here and on Audiokarma. They are in Barzilay cabinets that I've modified with battens and bracing to help reduce the resonance from the cabinets. I never felt the cabinets were doing the components justice and I've wanted to make new cabinets from the beginning but never had the time or skills to do so. I recently retired and a good friend of mine also recently retired and now we both have the time and he has the skills to make the cabinets. I'm using a custom crossover that Zilch designed based on the 4430 and made changes as he typically did. I don't specifically remember what the changes were.

For the new cabinets I have several questions that I'm sure the vast knowledge here can help me with. The reasons for building new cabinets are to tighten up the bass and improve imaging and sound stage with a properly designed cabinet. While bass is very important I'm willing to give up some lower extension for tight bass. I listen to mostly rock and pop music that has a lot of guitars and string instruments. My system is in a relatively small room that's 11'x12'. For the design I'm using my 4425's for inspiration along with 1400 Array's. Here are my initial questions:

1. The initial design has interior dimensions of 33" high, 16" deep and 13" wide yielding just under 4 cu ft of volume. What is a good volume for LE14H-3?
2. The cabinets will be made of MDF. What is a good thickness? I was originally thinking of 1.5" thick but maybe that's overkill?
3. For whatever thickness I make the cabinets should they be braced? See initial brace design.
4. In the initial design I have the waveguide mounted on a 3/4" plate similar to 4425/4430. The guide will be recessed in the plate and exposed. This could change depending on the answer to this question. How close should the waveguide be to the woofer frame. Zilch wanted them as close as possible.
5. What's the ideal depth between the woofer and CD? (time alignment) Is flush mounting them fine or should I try and optimize the depth between the two? See above about moving the waveguide further forward with a plate.
6. I'm planning on using two 3" ports. I could use one lager port but using two allows me to fine tune the bass as needed. Thoughts?
7. While I'd like to use the same components I have is there a better waveguide or CD for this application? I could add a UHF driver but that will be for another day.

Thanks in advance for any answers comments or suggestions you may have.

[Duffinator]

More images

[Mr. Widget]

I’ve been out of the DIY game too long, so I’ll let others advise where they can, but I think your Econowaves look very nice as they are... I will comment on your acoustic treatment. I assume those are fiberglass panels behind the speakers. Assuming that is correct, they won’t be very effective where they are. About 50% of their area is covered by the speakers themselves and the rest is directly behind the speakers. If you can move them to the side walls just a bit forward of the speakers you’ll likely improve your imaging.

Assuming you didn’t make any gross errors in the port calculations and bracing, you may not have all that much room for improvement in the box department. To tweak your bass, I’d look at room placement and possibly EQ.


Overall, a pretty nice system you have there.


Widget

[Duffinator]

Thank you.

The room is a bit challenged. I have two more of those panels on the other side of the room mounted up higher on the wall. They were an afterthought. A friend of mine removed them from his HT and I quickly bought them. He regretted that and bought replacement panels 2-3 months later. The room has two doors to the left and all windows to the right and is far from ideal.

Aesthetics aside I want to see what a more contemporary designed speaker cabinet can do for the components. The Barzilay cabinets are just a big thin box that I added some bracing to try and reduce the resonance.

[Robh3606]

They look nice! On the new cabinet I would watch that side to side brace. The diamond looks small and you don't want an undamped panel close to the back of the woofer. Also how long are your port tubes?? Don't want them too close to that same brace. Might want to cut holes.

Rob

[grumpy]

Might want to give this a look for fun:

https://sound-au.com/bafflestep.htm

I don’t expect you’ll be able to sneak it in at the crossover frequency (a trick to take advantage of difference in driver sensitivity).

[Dr.db]

As Ian has just mentioned, your room is nearly square so both room-modes kind of double up. Subjektivly you have ONE major peak.

Maybe a Helmholz-Resonator tuned to those specific frequencies is an option?

[Duffinator]

It seems like it's a very specific frequency low but not too low.

[Mr. Widget]

It seems like it's a very specific frequency low but not too low.

In my last listening room (living room), I had a nasty room mode that really clouded the bass and made my system disappointing with many tunes. I eventually isolated the mode by using Studio 6 Digital’s app called Larsa.

With Larsa I was able to isolate the peak and tame it with a high Q cut filter... all of a sudden my music library expanded and my satisfaction level went off the charts.


Widget

[Ian Mackenzie]

I would still try the port plug and see if it helps.

[Dr.db]

I would still try the port plug and see if it helps.

Me too!
Definitly try this first, as it doesn´t cost anything and may be sufficient.


In case you would like to tackle this problem further, there are basically two ways you can go.
Active filtering of the proplematic frequencies with a sharp notch filter as Widget suggested.
Or by using room-acoustik modules like helmholtz-resonators or membrane-absorbers.

GIK offers custom tuned membrane absorbers. You would have to measure the exact room-modes first, but that would be a great solution. Mind that you will need more than one modul, propably aprox. 4-8...
https://www.gikacoustics.com/product...bass-trap-t40/