Ported Heresy experiment

[ttaylor]

Well I decided to give the ported Heresy idea a try just to satisfy my curiousity(and hang out in the shop for the afternoon) I used WinISD to design the enclosure. It was 3.8 cu.ft. and used a 3.5" port. I knocked it out of 3/4 ACply using brads and liquid nails. Ugly but done in 2 hours. The result was just as predicted by WinISD. f3 dropped down to about 40hz and really rounded out the sound but it is still overwelmed by the mids. I did a sqwuaker attenuation on the easy-stuffing cheezecloth in the horn, and the sound was more balanced but still light on the bottom. My conclusion is that a sub is needed or a Cornwallotomy if real LF is needed.

Oh well, I now have a large test enclosure I can store with all the other crap I shouldnt keep.

taylor

[STL]

Do you have the T-S parameters for the Hersey woofer? If not, how did you model it in WinISD? BTW, I recently found a better program for enclosure modeling....it's called UniBox. It interface is a little raw (it's just and Excel file with macros) but it is more powerful than WinISD.

[hwatkins]

I use both WinISD and Unibox (actually also reference Boxplot) when building boxes. All three are very much in agreement when designing single ported enclosures, and I manually spot tested calcs on all three to validate mathematics. They are all quite handy, but i use all three to cover the bases. The specific features of each that I find attractive:

WinISd is a sound, very easy to use program. Fairly complete and is an exceptional startup sizing tool. It is weak on multiple porting and gives only text book utopia solutions.

UniBox is very nice on graphing the results of multiple ports. It can be a bit more confusing, but the detail in the data (such as port wind noise) can be very helpful. The ability to model is unlimited and it is accompanied by warnings and details that are very nice. Unibox really let's you model your compromises very well.

Boxplot compares most favorably to WinISD and is a simpler tool with one outstanding feature - you can provide two box dimensions and an automatic 'golden rule' calculation provides your 3rd dimension. Extremely helpful in building those odd shaped thingys like set top center channel speakers.

That said - thanks for the vented Heresy review. It matches what I was beginning to believe was the case. It seems if you want to improve bass in the box you may use a different woofer (or two) instead of working with the K22. It probably would introduce Xover work, especially considering the need to cleanly (and efficiently) cover the 700hz cross to the sqwuaker.

[ttaylor]

I got the T/S numbers that djk provided for the Eminence based driver.

http://forums.klipsch.com/idealbb/view.asp?topicID=9689

I also use Boxplot and check number with it as well. Both programs are easy to use and so far have provided good results. I am going to probably built dual subs based on the following design(using inexpensive Peerless drivers).

http://www.button.com/Russ/audio.shtml#subwoofer

Im not sure if I should use the Sonotube or built boxes that the Heresys can sit on. The latter kills two birds in that no stands are then needed. I would guess the XO point can go up if the subs are below the Heresys but need to be dropped if placed off in the corners.

Im also wondering why the Heresys dont have any stuffing/enclosure lining. Has anyone used Blackhole/etc behind the K22 and if so, is it worth the investment?

taylor

[hwatkins]

John Warren has a strong opinion that, considering the T/S of the K22, you get nothing from stuffing the box (in the original sealed) nor is it a reasonable speaker to vent. I can't vouch for that - The T/S seemed reasonable to me, but the models all still showed a weak low end.

My homebrew center uses Fostex woofs in parallel - and the bass extension and cross over to the Sqwuaker at 700hz is very clean. I used UniBox to model and determine that the full range Fostex that are so much used for back loaded horns and double bass reflex, actually were on the edge as a sealed box unit. Determining to tune to 50hz and use bass management on reciever to limit low freq to 80hz or higher - the unibox model prediction was pretty much right on to what I hear. With out unibox I may not have made that correlation with the Fostex. This may be an arguement for porting and filling with another woof instead of K-22.

Lastly - I have a non horn ported box I made that is Heresy sized with an Eminence Alpha 10 that has really been sweet - I am thinking of a 12" since this one is so sweet - it may be a consideration for you as well.

[John Warren]

Henry-

According to Small...

"There is no serious disagreement about the value of stuffing materials for damping standing waves within the enclosure at frequencies in the upper piston range and higher. The controversy centers on the value of the effects of these materials at low frequencies."

My contention is that the stuffing will damp standing waves, on the order of the "size" of the jelly roll placed in the enclosure (21" = 630Hz) which is near the crossover point.

John

[avman]

hey guys,

i picked up a pair of PERFECT raw birch 1985 heresey 2's about a week ago. i still have placement to play with,and am using 'loudness' on my pioneer receiver because i like the way they sound with it on better than with it off. i'm going to take home a rw-12 to see how they sound with it(it's easy,i'm a klipsch dealer )

anything else SIMPLE that i should try/be doing?

t.i.a.

avman.

[bsacco]

I'm in need of modeling a speaker box for the correct port size. THe box is:

Here are the dimensions:

The outer dimensions are 15.75 deep, 17.75 wide, and 29.75 tall.

The speaker is made from 3/4" wood, so I suppose the inner dimensions would 3/4" less all around.

Does the software you speak of model the correct port size for a speaker box?

I currently have ports in the speakers but each speaker port size is different. So I wanted to find out the correct port size so that I may make both of them the same size.

THanks

[hwatkins]

Well that is a can of worms in one post---

If you plan on starting with the box (not the speakers) you will have to calculate backwards (or is it sideways?) to come up with the reasonable T/S parameters to match both the interior volume and the existing ports. It requires quite a bit of learning to get to the point of figuring that out. If it is a passion to make this happen start reading loudspeaker design cookbooks, etc. that gives you a corelation that helps you figure out what you are looking for. I am quite confident that after a few hours (over several days) I could figure speaker parameters, but since I will not ever be doing that I decided I am too old (translates to too little time left) to do that calculation just for the mental exercise.

Good luck