Building a speaker around a 6cu ft enclosure

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#42
Or another JBL woofer, 2216ND how about the one out of the M2 or the -1 version, I have to
look up the difference, don't recall. I don't think used, worn out is worth it.
The 2216ND for the M2 is actually cheaper than the -1 version and I think it likes a
slightly bigger box which you have.
https://audiokarma.org/forums/index...l-2216-le15b-vs-jbl-2216nd-1-in-l200s.830641/

I don't recall how high you can XO these, but with active you can try just about anything.

You could buy the M2 waveguide someday (it ain't cheap) if you wanted a serious upgrade!

I'd try crossing to the XT1086 at 1.2 to 1.7K ish and see how it goes.
The ELX and JBL horns are so cheap it is worth a try listening to them, just sitting on top of
your boxes to see what you think - sometimes surprises happen. And the DE250 will work with
them all. Check for bolt on vs. screw for all of these.
 
#45
If you're up for using the 2216ND I'd suggest that you start a new thread saying inspired
by the LE14A Econowave work but now also by the JBL 4367.
The goal is to find the best horn to use with the DE250 and crossover settings for the MiniDSP.
If you like to tinker:
XT1086
JBL 6X12" Fairly certain that I have an extra pair of the Dayton clones, the China clones are better.
ELX
JBL 8X8" I have a pair of these that I'll probably never use.

The JBL 8X8" has surprisingly more output at the low end as compared to the JBL 6X12" which
should allow for a lower crossover point with far less stress on the driver.

You can also read the work on L200 and L300s and Nelson Pass' crossover redesign, I would not
go 3-way, it is too complex and without a coax horn driver can be worse than 2-way.
 
#46
Here are some posts about running some of these waveguides down to 1KHz EarlK says that
many of the popular drivers won't go that low but he also says that he's never tested the DE250:
https://audiokarma.org/forums/index...onowave-speaker.150939/page-919#post-16853587

I might not try to take that (DE250) lower than 1.2K, certainly check with others.
Remember that this is a home environment where the SPLs will be, probably, 10 dB less than
even a small venue live use, so you can, MAYBE, take the driver lower than spec.
 
#47
Here's the JBL 8x8" waveguide compared to the 6x12, red is the 8x8 and has about 12dB
more output at 1.2 KHz, that's A LOT: Edit: The 6X12 notch in this Figure doesn't show up in MTG's
measurements, indicating that the driver used was not a good match for the 6x12". Still the 8x8"
has about 5 dB more output than most at 1KHz, still very significant.
https://www.audiokarma.org/forums/index.php?attachments/h6512-vs-8x8-waveguide-png.2638180/

My thread on this guide:
https://audiokarma.org/forums/index...x8-waveguide-90x50-deg.1005288/#post-15833630

Part number for this WG: JBL PT-D95HF

But MTG calls it the AC895 and here are his tests:
Horizontal pattern control below 1.5KHz is not great but it is useable, this means that if you are far off axis
you'll have too much output at the frequencies where the pattern widens. Check this with all horns
that you're considering. Also, too small of a woofer will have the same problem.
https://www.mtg-designs.com/tips-tricks-tests/waveguide-shootout/1in-thread-horns/jbl-ac895

This is the JBL 6x12" WG also as tested by MTG, pattern is held fairly well to 1.2 KHz:
MTG calls this WG by the JBL part #338800-001, and he tests a very good clone:
https://www.mtg-designs.com/tips-tr...hootout/1in-thread-horns/clone-jbl-338800-001

The NLA QSC152i holds horizontal pattern fairly well down to 900 Hz but I don't know which if
any 1" driver would be workable that low.
https://www.mtg-designs.com/tips-tricks-tests/waveguide-shootout/1in-bolt-horns/qsc-pl-000446gp

Surprise, the XT1086 has about 5 dB more output than most of these WGs, comparable to the 8x8" at 1KHz,
and it hold pattern fairly well to about 1.2 KHz. I'd certainly try it at 1.2K maybe even 1KHz:
I'm liking this guide more and more, good that there's a clone.
https://www.mtg-designs.com/tips-tr...ut/1in-bolt-horns/eighteen-sound-xt1086-clone

I'm using the point where Red output hits 60 deg as the freq where the pattern is getting too wide.
 
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#48
For crossing a 15" at 1000 hz, I suggested a 1.4" CD instead of a 1". N314T-8 is 2 db down at 15000 hz 7 db down at 17000 hz and 12 db down at 20000 hz, but 99.9% of males cannot hear that high. My hearing stops at 14000 hz. Suggest the OP do a hearing test with headphones. OP has already bought his B&C DE250 1" which is okay to 18000 hz, gone at 20000, but drop rapidly below 1000 hz. Recommended crossover is 1.6 khz.
While 6 db/octave filter is okay on top of the 15", it is usual to put a 12 db octave low cut (2 elements, inductor and capacitor) below any CD limit. CD rattle or exceed xlim below their limit.
It is usual to put 18 db/octave low limit below woofers Fs, usually 45 hz. 25 hz sources are rare with CompactDisks and MP3, but LP can go way low with a needle on a record and a listener walking across a wood floor. I tore the laces off a 10" woofer that way. Most electronic crossovers for subs have this filter built in the mains channels. (Rane, Nady, Peavey) The low cut filter in my RA-88a disco mixer is 6 db/octave, one series capacitor, and offensively audible.
 
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#49
In the process of reading some older threads I came across a statement by Zilch that Geddes
has crossed the DE250 as low as 1KHz. I expect that 1.2K will be fine.
There's a version of the common 6X12" JBL that takes a 1.4" driver if that is of interest, for
now he has the DE250 and horn. And obviously many others that take 1.4" drivers as needed.
Most 1.4" WGs have trouble at the top end of the range, Zilch tested the JBL and it is quite good.

Highpass to make a B6 is second order peaked, for a strict B6 6dB of peaking more or less
can be used as needed. MANY LPs have bass attenuated whereas CDs have no need for
that and it is obvious to hear. 5 and 6 string basses have become popular that have
fundamentals to 32 Hz. I have speakers that will play into the 20s with ease and it is
surprising what is missing with a speaker that plays to 40-45.
 
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#50
For some context, I jumped on an "open box" discount on PE for the DE250.
I will likely have the horn on top of the speaker cabinet as I begin getting into this.
Since I'm trying to match a woofer to my enclosure, I have to accept that I might have to spend a bit to get a good woofer.
I've window shopped the various options for CD and horns that have come up here and in my research. Loads of options – but fairly pricey, in general.

The vision for the project now is really that this enclosure is a bit of an experimentation platform. I'd love to see how a 1.4" throat horn setup changes driver behavior, for example.

As it stands, I have about $600 to spend on a good pair of woofers that will sing in 5–6cf BR enclosures and can cross to my DE250s around 1.2khz.

In terms of low-end extension.. I'm still learning what's achievable and what's wishful thinking. I'm flexible, but I know I wont be shelling out for a 3channel DSP anytime soon, so no flanking subs, three way builds, etc.
If the 15PR400's were available at EU prices I would move forward with that. In the meantime, I'll continue trying to find other viable options and lie in wait for deals..
 
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#52
chirs said:
As it stands, I have about $600 to spend on a good pair of woofers that will sing in 5–6cf BR enclosures and can cross to my DE250s around 1.2khz.
Click to expand...
Two Kappa pro 15lf are $420 at P-E,. free freight. Will easily go to 1200 but do not use above that. There is a bump from 1000 to 1200 that would require some crossover control. Possibly tuning the high cut woofer crossover for 1000 hz.
 
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#55
Question for the group.
Let's rewind and say I hadn't selected a CD/horn yet.

Are my woofer options better if I go with a 1.4" CD that's able to cross at 800 Hz?
I'm wondering if the strategy of spending a little more on the horn & CD and opening up the possibility of crossing at a lower freq. will give me more options for affordable woofers.

For example:
Faital LTH142 & HF146R – $500 (used)
Lavoce WXF15.400 – $340 (pair, new from PE)
MiniDSP – $200 (used)
----
$1040

No idea if that Lavoce is any good, but it does seem like there are some more options if I'm not worrying about woofer breakup at 1k and beyond.
Some others that appear to be new possibilities with this setup:
Dayton DC380-8 ~$200/pair
Dayton Pro 15" 15MB500N-8 ~ $300/pair
likely others..
 
#56
You need to learn to download the datasheets and do the engineering yourself if you wish to save $$.
People copy other people's work because the engineering is done. See Asathor, a sealed 15"+CD speaker that has a lot of fans. https://www.diyaudio.com/forums/multi-way/367215-asathor-jbl-4367-clone.html?highlight=asathor
I found the lavoce datasheet with the bing search engine. It has some frequency bumps between 1000 and 1300 which may be resonances. The VAS is 9.1 cuft.
I did not bother to look up your used CD finds, you can do that. I bought used Peavey A22 with horns for $140 the pair shipped. They work but building a box for the woofer is a real barrier to a mechanic but not a woodworker.
I think crossing a 15" to CD at 800 hz is old school, Peavey has not done that since 1980 in their SP2 line. But it is your project, do what you want. I am copying the SP2(2004) as best I can.
I do thumbnail design with the tables and formulas of David Weems Designing Building and Testing your Own Speaker 4th ed which I put into the calculator function of this PC. Other people prefer to use Windows dependent utilities like winsound or vituixcalc . You see on the news what the implications of being dependent on Windows are. United Airline still has not recovered from the crash 3 days later.
I will say this about bargains. You have 30 days usually to measure your bargain and determine if it meets specification or not. That measurement of a driver is a difficult process. Some products, the variation from unit to unit may be a problem. Others not.
On the subject of bargains:
I have been buying bike motors off ebay for 5 years, have worn out 2 at 3000-5000 miles, and burned up a 350 w one which was too small for my needs. Ebay has coelesced on one brand which is rather cheap and has to be imported from the country of origin. I put one in the garage last fall in case the one I was using wore out. My favorite $700 1000 w motor wore out in June. No longer available in the USA. I built the new 500 w motor into a wheel, started out to the hills and got 6 miles before power failed. There are 9 wires, and one wire was 0.5 mm short of reaching the pin of the connector. The factory bridged the gap with solder, and when I started demanding 300 of the 500 watts it was rated for, the solder melted out. I have just spent two weeks correcting the factory's quality issue. Note in the lower end of the market, this sort of thing happens. If I wanted sure quality I would buy a new bicycle for $$$$ and throw the one with 12000 miles on it away. The new defective motor was $280.
I bought one 10" GRC woofer from PE 5 years ago, for replacement in a sealed cabinet that I had torn the leads to the woofer by walking across the floor. I intended to donate it to a church where the lead donor had complained about a Peavey 1210 I had donated having too much bass. The 1210 had two 10" woofers in a reflex cabinet. The GRC met expectations @ 88 db sensitivity. In a sealed cabinet it had hardly any bass. Sometimes cheap is just right. That church since has taken out the speakers I donated and replaced them with 6" woofer thumpers. 10" woofer was probably too much bass for them.
 
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#58
Pink noise that Peavey tests watt rating of speakers with, has a lot more energy in the bass than the treble. CD's with 2" coil have lower watt rating than woofers with 3" coil or more. The 1980 SP2 that crossed at 800 hz had AES watt rating of 175. Nobody bought them for hifi in those days, PA use only. Crossing at 1200 hz the 1995 SP2 had 350 watt rating. The sound was accurate, I owned 2. Crossing at 1800 the 2004 SP2 has watt rating of 500 and an actual harmonic distortion spec (which is very rare). The 2004 cabinet has a pinched back and folded rubber sheet inside to make 6 db dispersion 90 degrees. I do not think you or I can copy that. We can perhaps copy the design features that make the harmonic distortion so low. Peavey built the 2004 SP2 with a 4 part crossover, which keeps unit cost low. The more passive crossover parts you buy, it is about $20-30 each. Asathor that uses a Lavoce WSF 152.50 woofer has 14 crossover parts. Use the DSP, run two amps every hour you listen. 2 amps heat up your room, and it is certainly hot these days. I make do with one amp drivng 2 SP2(2004), and one window A/C. 245 kwh the month of June for 1300 sqft which the electric company tells me is 1/3 of what an efficient house uses.
 
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#59
@chirs First, let me say that I think that you made an excellent choice with what you have.
It might be "fun" to try some alternate 1" WGs as I already suggested. The JBL 6x12" is a
good reference for comparison but no pressure you have a lot of work to get it all set up.

To answer your 1.4" driver question, go here, scroll down to the 1.4" section and
look at the curves. They are BAD. I might blame some of the issues on there not
being many PT or true OS guides in that group but at least one of the Denovo's
IS an OS guide but doesn't look very good and it is NLA.

If you want to spend close to $1000 on the JBL waveguide and two way driver
then sure, go to the larger driver but otherwise go with what works. Remember
that Jackgiff and many others have built Econowaves crossed higher than 800.
Also, note that Geddes' horn in the Summa (NS15) was huge something like 15".
 
#60
Here's the link:
https://www.mtg-designs.com/tips-tricks-tests/waveguide-shootout

Here's a JBL 1.4" that's probably PT but the top end is not very smooth, better with the Celestion:
https://www.mtg-designs.com/tips-tr...tout/1-4in-horns/jbl-352606/jbl352-cdx14-3060

The GEddes White Paper on the Summa hints about the crossover being around 900 Hz, and he uses the 1"
B&C DE500 in the NS15 which is rated for 1500 Hz in PA applications.
Does this link still work? For some reason it bounces to my local copy on my drive:
https://www.avsforum.com/attachments/summa-cum-laude-geddes-pdf.14618/
 
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