Zilch's AK Design Collaborative - Econowave Speaker

[greg_mitch]

I will most likely cross them at 80Hz at the receiver. For shits and giggles I ran it with a 2cu. ft box vented by 2 x 4" ports that are 12" long (each I think).


Not sure if designing in that extra low end will even benefit me when I cross it at 80Hz anyway??

Also...any laymens explanation for what the inductor and capacitor in the LF crossover portion are doing to the response and how that interacts with these WinISD models I am running?

Appreciate it again.

Any comments on designing ported vs sealed and crossing over at 80Hz relative to the chart I posted?

Is there such a thing as frequency range head room? Would it matter that the box and woofer can go to 50Hz if I cross it at 80Hz at the receiver?

Thanks.

 

[fastbike]

It matters some. You'd like to cross at a point that's still fairly flat response. Porting a 2 cu ft box and crossing at 80 Hz doesn't make sense to me. You lose a lot of power handling capability when you port. Then again, the speaker probably won't exceed xmax at 80Hz.

Any comments on designing ported vs sealed and crossing over at 80Hz relative to the chart I posted?

Is there such a thing as frequency range head room? Would it matter that the box and woofer can go to 50Hz if I cross it at 80Hz at the receiver?

Thanks.

 

[dnewma04]

Actually, at the tuning frequency and above to about 1 octave above it, you will get significantly more power handling by going ported.

 

[GordonW]

GordonW,



Do you have a link to the activities?

Any who attend diyAtlanta may want to stop by :thmbsp:

www.awa-con.com

Sept. 17-19, 2010. I'll be there setting up on the evening of the 16th, for anyone who wants a sneak peek. We usually have the Big Reds (dual-18" towers) and SEELES (set of four 18" bandpass subs) up and running, Thursday evening, for sound check (our excuse to play the anime music videos with the most outrageously loud and low bass possible, at the highest volume possible )...

As for where my handiwork will be placed, during the weekend:

If completed (and it's looking to be on schedule), the new E-waves will be in Video Room 1, in the Chambers Room in the Waverly Hotel. They will be accompanied by two Dayton Quatro 15" self-powered subs, and run from a combo of a Marantz SR4400 HT receiver and a Carvin HD1800 pro amp.

Next door, in Video 2 (Stanhope Room), will be a pair of custom-built JBL 12" 3-way speakers, a modified JBL L26 for center channel, and a modified pair of EPI 100V for rear speakers, accompanied by a pair of custom subwoofers using Speakerlab W1208R 12" woofers and 15" passive radiators. This will be run from a Marantz SR4600 HT receiver and a Rotel amp for the subwoofers.

The Little Reds (dual 15" E-wave) will be used on Saturday, in a panel room located in the Williams Ballroom of the Cobb Galleria Centre. They will be run from a Carvin F600 pro amp.

The Big Reds and SEELES will be used in the Video Art Track room (music videos and other fan video art), in the Habersham Ballroom in the Waverly Hotel. The Big Reds are run from a Carvin F1200 pro amp, and the SEELES run from a pair of big Hill Audio DX1500 pro amps.

Regards,
Gordon.

 

[GordonW]

Actually, at the tuning frequency and above to about 1 octave above it, you will get significantly more power handling by going ported.

QFT. You can significantly lower IM distortion, even if you're crossing over higher than the LF rolloff point, by going vented.

I'm doing this, just for this reason, in my three E-wave cabinets for AWA Video 1. The crossover in the Marantz 4400 is at 60Hz (IIRC), but even though the cabinets could do that sealed, I'm still going to go vented... because by doing so, the power handling stays flat, down to nearly an octave below the crossover point... whereas sealed, it starts to drop slightly ABOVE the crossover point...

Of course, this assumes a suitably LOW vent frequency. You want the vent frequency to be around 1 octave below the crossover point, for max power handling and lowest IM distortion. Above that, and you can get significant woofer "unloading" at, and just below, the crossover point to the subwoofers...

Regards,
Gordon.

 

[truth seeker]

Any comments on designing ported vs sealed and crossing over at 80Hz relative to the chart I posted?

Greg, Along with the other good reasons above, with the port you retain the option for further "tuning" in-room. The x-over can be lowered...the port can be stuffed to suit room conditions...

Gordon, You are busy! I hope I can find the time.

 

[blvdre]

The measurements in Brandon's Driver Vault show it starting to lose pattern control up around 2 kHz, and 1.2 kHz is likely the lower limit of its utility in this regard.

It's a large waveguide, but much of that size is taken up by the substantial built-in roundover at the mouth, the "business" portion being roughly equivalent to the standard eWaveguide, which is also confirmed by the measurements.

The answer, then, is yes, driven by a general-purpose compression driver rated to play that low, it will play down there, but only with significantly compromised functionality.... :thumbsdn:

Thanks for the info Zilch. Reason I asked is that I was wondering if it would be feasible to do a two-way with a 15" (that would obviate the need for sub, at least for my needs). I've read that I'd want to cross ~900Hz, as the beamwidth of the 15" and compression driver (on a waveguide) will be similar at that frequency. Not sure if this is accurate or not - the poster qualified his statement as a generality.

If that's the case, then I'd need to source an appropriate waveguide and driver. Maybe one of the DDS offerings mated to a BMS 4550, or even the B&C DE250?

 

[my89_928gt]

I need some input here.
I have picked up 3 JBL Horns and D220ti. I am planning a LCR for HT. I will cross them with my reciver at 80hz (no more than 90) to my SVS sub.
I will be building the boxese as well.
My first thought was 4 Tang Band W6-789E 6-1/2" Woofer in a 2 way. With 4 of them that puts the mid-woofer at 101db 1w/1m. Great I thought. But, I read the woofer should be under 101db 1w/1m. If I do away with the L-pad would this be ok?
This may not quite fit in the Econowave area as with that many mids price dose climb.

 

[donprice]

The eWave HF section does max out at around 100 dB (@1W@M) but I doubt 101 on the LF would be a deal breaker.

I take it you thinking about 4 TBs in each box like a MMTMM design.

 

[greg_mitch]

Of course, this assumes a suitably LOW vent frequency. You want the vent frequency to be around 1 octave below the crossover point, for max power handling and lowest IM distortion. Above that, and you can get significant woofer "unloading" at, and just below, the crossover point to the subwoofers...

Regards,
Gordon.

Can you explain a bit more on "vent frequency"?

Also...good point on flexibility after the fact. It seems I could essentially stuff the ports later and get back to sealed response?

 

[rkeman]

In the process of finalizing plans for home theater and music system based on CD horns and 12" to 15" woofers, a number of possibilities have presented themselves. These include the Econowave deluxe and several of the Pi speakers variants, specifically the 3 Pi using the B&C DE250/Eminence 290 and Acoustic Elegance TD12S and the 4 Pi with the B&C DE250/Eminence 290 and JBL 2226h. The Geddes Abbey looked promising; however, the kit is not available without cabinets and is significantly more expensive. Are there any opinions regarding the relative merits of the AE and JBL drivers compared to the Eminence Kappalite 3012LF particularly in regard to midrange (500Hz to 2,000Hz) performance? Also, how would the QSC waveguide fair in comparison to the Eminence horn using the commonly shared B&C compression driver? Cost is an issue, but because the bulk of the investment will be the time in cabinet construction regardless of the design chosen, starting with the most capable seems to be the prudent course. Any experiences or thoughtful conjecture would be greatly appreciated.

 

[Zilch]

Any experiences or thoughtful conjecture would be greatly appreciated.

Let's not confuse me more than I already am, now, it's KappaLite 3012LF, not Delta, I believe.

In any case, the "Lite" part, derivative of neodymium magnets, is a major advantage, in my book, after years of slogging big ferrite woofers around. :yes:

I just don't see the value in using 15" woofers for HT builds having subwoofers, and there clearly are compromises associated with them which are not, in my view, outweighed by prospects of seeding as a Johnson Award contender.

AE is de rigueur currently, but I have considerable difficulty justifying the substantial cost differential in this application.

I certainly like the QSC waveguide, and have in significant part confirmed Brandon's measurements of its performance. I have zero experience with the Eminence 290 as alternative.

As you have already observed, there doesn't appear to be much to criticize regarding the B&C DE250 compression driver used within the limits of these designs.... :thmbsp:

 

[greg_mitch]

Any other reputable sellers for the B&C DE250? Parts Express is out.

I have time to wait...but money is burning a hole in my pocket right now...the sooner I get the parts, the sooner the things get built!

I see that Alpha Electronics has them in stock and cheaper with free shipping...but....

 

[skywave-rider]

http://www.usspeaker.com/homepage.htm

Don't know if they're in stock, though.

 

[Zilch]

http://www.prosoundservice.com/m9_view_item.html?m9:item=BC-DE250

OR, just place your order with PE, and they'll take your money, backorder the item, and ship to you when they come in....

 

[my89_928gt]

The eWave HF section does max out at around 100 dB (@1W@M) but I doubt 101 on the LF would be a deal breaker.

I take it you thinking about 4 TBs in each box like a MMTMM design.

Yes, that sounds like that should still work just fine.
Yes, I am thinking of MMTMM. I know for the ctr that is supposed to be bad. I do have the spouse aproval factor to consider, lol. Not sure if it would help things but, thought of angleing the baffles for the mids ever so slightly on each side of the horn. Could this help or am I just worrying to much?

 

[fastbike]

Okay, help me out. I'm fairly new with box modeling. When I have run Unibox w/ a given set of parameters, I exceed Xmax at a significantly lower power level w/ vented than with sealed. Am I misinterpreting, running something wrong, etc. I know I have heard Zilch and others talk about less power handling.

The sims I've run have typically been tuned to ~30Hz vented and Fb~48Hz sealed everthing else the same. Thanks

Actually, at the tuning frequency and above to about 1 octave above it, you will get significantly more power handling by going ported.

 

[Zilch]

It matters some. You'd like to cross at a point that's still fairly flat response. Porting a 2 cu ft box and crossing at 80 Hz doesn't make sense to me.

Look also at the shape of the curve above 80 Hz. Properly chosen, a ported alignment will be flatter, because the closed box is rolling off below Fc, whereas in a vented one, it's below Fb.

Okay, help me out. I'm fairly new with box modeling. When I have run Unibox w/ a given set of parameters, I exceed Xmax at a significantly lower power level w/ vented than with sealed. Am I misinterpreting, running something wrong, etc. I know I have heard Zilch and others talk about less power handling.

Using BB6P, I run 3012LF in 2 cuft gross and at 450W Pmax it runs out of its 9.1mm Xmax at 25 Hz vented and tuned to 30 Hz, or at 50 Hz, closed box.

[Not that we'd be using it at those levels.... ]

610043/10336=59.0212​

 

[lredelfs]

Waveguide in klipschorn

Has anyone tried the Jbl PF-D95HF-1 in a Klipschorn? I am impressed with the comments on the natural sound of the waveguide and if feasible, would like to try as the HF unit in a Folded horn with a three way system.

Larry

 

[fastbike]

Sorry, I'm still having a dense moment. In the sims I've run, I might exceed xmax @ 20 watts w/ a vented alignment yet not exceed xmax @50 watts in a sealed box, driver and box sizes the same.

Using BB6P, I run 3012LF in 2 cuft gross and at 450W Pmax it runs out of its 9.1mm Xmax at 25 Hz vented and tuned to 30 Hz, or at 50 Hz, closed box.

[Not that we'd be using it at those levels.... ]

610043/10336=59.0212​