2-ways

[Earl K]

Hi Jorg,

Glad to see you're doing some of the necessary leg-work on your diy project .

Yes, once you add in some LF room-gain / I believe the tunings you just posted will be a bit rough sounding .

A couple of notes :

(i) Set your programs vertical scale to something a little less drastic to look at ; ie; 3 db or even 6 db .

(ii) Look at tuning up the 2235H in a 4.5 to 5.5 cu ft box tuned to around 30 hz for a start .
- Your SIMS are tuned abit too high, in boxes that are a bit too small ( IMO )

[89-300ce]

How is this?

The room is 22x14 and is a dedicated listening room.

I have to read up on room effect!

Jorg

[Earl K]

Jorg,

Using the search engine ;
- Look for "Banana Curve" with either Giskard , Zilch or RobH3606 as the author . You should be able to find an existing pic showing a tuning for the 2235H known as the banana curve ( done in BB6P ).
- It has become a desirable curve that interacts well with room gain ( though I can't say I've really tried it ) .

- Or Alternately, play around with your simm software until you get a curve that has a slope shaped like a banana . ( try 4.5 cu' at 25 hz ).

- And switch your vertical (db ) scale to something less drastic / you'll never see the banana at that resolution .

<> Earl K

[89-300ce]

Here are two curves.

The yellow is 4.55cu.ft. - 29Hz
The white is 4.5cu. ft. - 25 Hz

I suppose the white looks more banana to me, but, ... the other curve is "yellow".

Jorg

[4313B]

I used the 4.55 cu ft @ 29 Hz for a pair of 4430 clones and it worked quite well.

Tuning 4.5 cu ft lower to ~ 25 Hz is basically a JBL Model B380 alignment.

[Earl K]

Okay,, good enough for now .

- Something to remember , tuning ports ( ducting ) can stick outside the cabinet / allowing one to play with different lengths of ducting. This way one gets to find a tuning that works & sounds best within their own environment.

- I always recommend that people make test cabinets before doing the real thing.
- If you decide to ignore that advice / at least make cabinets that are simplistic enough that they can be covered/veneered easily & have some form of easy entry ( to add extra bracing if your first attempt resonates ) .

[89-300ce]

I used the 4.55 cu ft @ 29 Hz for a pair of 4430 clones and it worked quite well.

I believe that's where that curve came from.

Jorg

[89-300ce]

Okay,, good enough for now .

- Something to remember , tuning ports ( ducting ) can stick outside the cabinet / allowing one to play with different lengths of ducting. This way one gets to find a tuning that works & sounds best within their own environment.

- I always recommend that people make test cabinets before doing the real thing.
- If you decide to ignore that advice / at least make cabinets that are simplistic enough that they can be covered/veneered easily & have some form of easy entry ( to add extra bracing if your first attempt resonates ) .

Good advice. I can temporarily mount the duct/s, play with them, and then permanently fasten the optimum duct.

Location of the LF driver.
Because I think there will be some imaging information coming from the woofer I'm considering centering the LF driver to my ear and mounting the horn in a fore/aft and tilt adjustable manner as close as possible above. I would try to keep the cabinet as narrow as possible, just wide enough to mount the woofer, with an insert over the baffle to flush out the woofer (for cosmetics). The height of the cabinet is determined by the woofer centred to my ear and the depth is set to get my proper volume. I only need a sweet spot for one so the tilt on the horn should be ok? I'd like to stay away from any re-enforcing from the floor so the high woofer should be ok?

Jorg

[Earl K]

Jorg,

A few thoughts,

(i) Let the width of a wide horn dictate the width of your woofer cabinet . It'll look nicer .
- the 511 is @ 24 " / so go for a cabinet width in that area .
- if you go with a smaller dimension for the width of woofer cab. / I think it'll look goofy ( IMO ) .

(ii) Don't be in a hurry !
- Use a draw program ( or a CAD package ) to lay out the component "looks" and arrangements.
- "Know" that you are going to enjoy the "look" before you actually build it . So use draw programs as visual aids.

(iii) The center of horn should be at or near ear level .
- For many people in a typical chair, that means around 34"
- Take a measurement with you in your chair ( center of ear down to floor ) & make that dimesion ( more or less ) the center of the 511 .

(iv) The woofer should be close to the horn for good acoustic summing .
- Follow advice (ii) and then layout the woofer just under the horn.
- Then make note of the distance of floor to center of woofer. ( & come back for more advice )

(v) Buy a DIY bok from Solen ( Canada ) on cabinet construction .
- I'm not sure what is the current favourite book / perhaps it is "Bullock on Boxes" . Do a search to find out ( OTOH; maybe it's Vance Dickasons' book ) .

(vi) Don't be scared to look down the throat of a compression-driver/horn combo.
- If you are for some reason , then you're looking to build the wrong project.
- ie; Don't "push-way" the horn like some sort of "foul-smelling fish".
- If you're not willing to work through the challenges presented by horns / then drop this project .

(vii) Most of the imaging one will enjoy from a horn/baffle-mount woofer hybrid , comes from the horn.
- So forget about giving the woofer preference to your ear-level .

<> Earl K

[Earl K]

Here's one "look" ( tallish ) that incorporates a 511 and a 15" woofer ( as well as a tweeter ). These are owned by "Wardsweb" and were built by Mr. Widget . I believe that overall they were close to being 4.5 cu foot in volume . Widget ?




Here is the cabinet with metal protection sceens in place .





Here is the "look" when the screens are covered by Zilches' official JBL blue grill cloth .



The cabinets in the above pics were still in their raw unfinished state and were to be eventually finished with this veneer .



The above pics came from Wardsweb DIY Saga.

As I've mentioned, I'm personally, just as drawn to a squatter look when 511s are paired with 15" woofers .



Jorg, ( for the near future ), I'm taking a hiatus from commenting on this DIY project . It is afterall, your DIY .

[89-300ce]

Not a problem. Thanks for all the help and the link to Wardsweb diy.
I'm pretty much done for now as well. It's summer so it's boats and cabins for me. I'll procure more components over the next few months and draw out some cabinet designs so I'm ready to begin construction when it snows.

Jorg