Vifa Xt25 + P13wh + Dayton RS180-8 your thoughts?

[K-amps]

Guys need your input on this planned 3-Way.

I have been going back and forth on driver selection. I ditched the Dayton 2" dome in favor of the P13WH that many on the forum like.

Objectives are having a versatile system that is capable of hi-end sound as well as ability to take abuse from my big SS amps without "poofing" up or blaring. I am ok with F3 of 50Hz at -3db.

So far I have come up with a rudimentary design with MTM with the Vifa and XT25. 2 Vifa's in Parallel will give me 4 ohms same as the Xt25. Crossover will be at 3kHz .

Two Dayton RS180-8's will be paralleled for again 4 ohms and crossed over at 180Hz. Rudimentary box design pic is attached.

Any ideas /thoughts/ comments are appreciated.

K-

 

[K-amps]

ok..... I see everyone is just as clueless as I am

 

[planet10]

Put the 2nd woofer on the back (or in separate push-push box)... and XO where baffle step starts (you could put the 2nd mid on the back for that matter too....

dave

 

[K-amps]

Thanks Dave,

Speakerbuilder noob here so please share your thoughts on the following:

1) What do you think about the driver selection/ interaction?

2) Putting a mid on the rear would reduce output on the front, it would also lose the D-appolito configuration... obviously you think it does not matter hence your stance... can u explain?

3) Baffle step... for time alignment?

4) Why put woofer on the rear?

5) What is push push? Isnt that the way it is? or Is that where one driver is installed on the rear but cones of both are oriented towards the listener.

Thanksa again!!

 

[mazeroth]

Why not go with an RS mid and the new RS tweeter?

 

[K-amps]

I already have a Dayton tweet and when I swapped the XT25, my jaw dropped. It sounded so much better..... so much better, I cannot believe domes could sound so good for the money.

Also many peeps have said that the P13Wh's are excellent mids, I have heard this from members, moderators, speaker designers etc etc.

No need to make a complete RS system.... I don't see the advantage unless I wanted to call it an RS system.

By the way, have your heard the RS mids and tweets, whats your opinion?

thanks!

K-

 

[mazeroth]

The only RS series I have heard are the RS125 (5") and the RS150 (6"). Both sound very, very nice to my ears, but do require a steep crossover to avoid the harshness later on in their response.

The RS tweeter just came out and is getting rave reviews over at the Parts Expres Tech Talk forum. Follow this link and scroll down a bit:

http://www.pesupport.com/cgi-bin/config.pl

Also, here's the link to the new RS series tweeters:

http://www.partsexpress.com/webpage...301&filter=diaphragms&raid=25&rak=275-130/135

If you already have the XT tweeters, you might as well use them.

 

[K-amps]

I already have the Xt's plus the XT's were cheaper....

 

[critofur]

Why not go with an RS mid and the new RS tweeter?

Because the RS mids breakup is so nasty Zaph even said said he prefers the cone on the DA175 to the RS: "Honestly, I like the DA175 cone better than the RS180 cone. Much more controlled in the upper midrange, and a less harsh breakup without the twin peaks."

I don't usually like metal cones sound, though there are rare exceptions.

Of he RS drivers I think I would like working with are the RS225 and the RS100 - RS225 for a woofer, crossed over fairly low, and the RS100 looks like it only needs a notch filter to control it's breakup. Oh, and the tweeter looks ok too, but I wonder if it has any advantages over a Seas 27TDFC or TBFC/G? I often also tend not to like metal domes on tweeters, but, I haven't heard most of the better ones yet...

I have a couple of the RS100s to play with.

But I would really like to try the P13 after hearing the P17s I just picked up at the PE tent sale for $14 ea. Can't keep just buying all the drivers I want to try though, until my wife finishes college, or, I get a much better job...

K-amps: what did you end up doing? Did you build a speaker with the P13 and XT25? Seems like that could be a real nice combination, with the XT25 having great potential if you cross it over 2,5Khz, and the beautiful smooth top end of the P13, not to mention, it's excellent sensitivity for the size...

Gainphile even said of the P13WH "Arguably the best midbass in existence."

edit: I was searching for more opinions on the P13, didn't realize how old this thread was, so... I made another reply and tried to answer more thoroughly, to at least make the thread useful, in case the OP is long gone...

 

[critofur]

Thanks Dave,

Speakerbuilder noob here so please share your thoughts on the following:

1) What do you think about the driver selection/ interaction?

The P13 has such a nice extended response and smooth roll off, it should work well with most tweeters, and be an excellent match w/the XT25.

2) Putting a mid on the rear would reduce output on the front, it would also lose the D-appolito configuration... obviously you think it does not matter hence your stance... can u explain?

Bipole is an interesting design approach, but, not used nearly as commonly as MTM, TM, etc... We can guess that there must be a reason for that? Though I do advocate placing a tweeter on the rear for more even "power distribution".

3) Baffle step... for time alignment?

No, he's not refering to a physically stepped baffle, "baffle step" is something different... Look up "baffle step compensation" or "BSC" - the on axis response will be made uneven by the boost of radiating into "2PI" vs "4PI" space, this boost varies as the frequency changes due to the change in the wavelength of sound corresponding to the size of the baffle affecting directionality of the output.

4) Why put woofer on the rear?

To make a bipole configuration, it affects the BSC, you'd probably want to google "bipole" for more info on that.

5) What is push push? Isnt that the way it is? or Is that where one driver is installed on the rear but cones of both are oriented towards the listener.

Huh? If one cone was on the rear, then it couldn't be pointed at the listener, but perhaps you mean mounted so that the back of the cone is sticking out? That is one way of doing it. "push push" with one mounted on the rear means that both drivers are in phase, both have their cones "pushing" out or in at the same time. If one cone was mounted with it's front face expose and the other with it's backside exposed, then they would be wired out of phase, but they would still be in phase, because one is reversed. Some people would say that some of the distortion coming from the back of the cone will be different from that coming from the front, and setting them up that way could be slightly superior due to that.

If one cone was mounted on the front and one in the back, except in a "push-pull" configuration then that would be called dipole (I think, is there a more specific term when using two woofers vs open baffle dipole?) though the more common way to do dipole is "open baffle".

 

[Mos Fetish]

Not too sure why you'd put the P13s in parallel. Or have two at all. Why not just build a nice 3-way with one P13?

In a 3-way, there's midrange gain to consider. Any crossover software will show you this. Therefore it's not necessary to match the impedance of the mid to the tweeter--the gain will cover it. In fact, you may end up doing things to damp the mid. If you use two mids to get a lower impedance, they'll dominate for sure.

Mos

 

[critofur]

You could put two P13s wired in series if you wanted greater power handling, or, if you wanted to crossover lower than you would otherwise want to with one of them.

Personally, I think one P13 crossed over to a quality woofer or two should be able to play plenty loud.

Say, one P13 crossed over to a couple RS225s at somewhere around 200 - 300 Hz, then matched with a good tweeter, could make a very good sounding system capable of high output for something not based on pro-sound drivers. (or, do the RS225s in a 2.5 configuration to cover (part of?) the BSC)

I'm not aware of a crossover where the top part of the BSC is done on the mid but the bulk/lower portion of the BSC done on 1 of 2 woofers?

Another interesting configuration would be one P13WH, and four Tang Band W6-1139SI 6-1/2" Subwoofers wired series/parallel for the same net impedance as one but greater sensitivity, and a healthy amount of output below 30Hz. All on a narrow front baffle.

 

[clm811]

Crossover for P13's and Xt25

I've been using these drivers in an MTM for a couple years now with a 3rd order X/O at 3kHz and recently upgraded the tweeter caps to film & foil.
Great sound and nice, flat response in a vented enclosure (f3 is arount 70Hz).

Here is my crossover if you care to try it; the Lpad resistors can be adjusted/omitted, depending on your taste.

-chas

 

[sreten]

Hi,

The RS180-8 at 85dB each mean the mid range will be ~ 85dB
will full BSC and 88dB with 3dB of BSC, basically you do not
need 2 P13's, one will be fine, unless your planning no BSC.

/sreten.

 

[critofur]

Hi,

The RS180-8 at 85dB each mean the mid range will be ~ 85dB
will full BSC and 88dB with 3dB of BSC, basically you do not
need 2 P13's, one will be fine, unless your planning no BSC.

sreten: funny you should mention that, I was just thinking of using two RS225S-8 and one P13WH. After taking a second look, and thinking I don't want a larger cabinet than 2 cu feet, perhaps a pair of the RS225-4 in series would be better?

For a long time I had been thinking I want to try to do first order xovers, but, after reading Kreskovsky's article on transient perfect 2nd order crossovers, I'm having doubts about 1st order... : http://www.geocities.com/kreskovs/CrossoverdocN.html

It was surprising (and not intuitive, to me at least) that "full range" drivers are not good square wave reproducers...

But then again, I think (?) most studies suggest that poor square wave reproduction does not nesc. mean inferior sound, and may not be audible?

The next step for my learning about crossovers is how to design linear phase passive crossovers, my gut feeling has always been though, that I want to keep crossovers simple, with minimal components...

Can excellent phase characteristics be attained with 1st order series crossovers?

I don't yet fully understand what an "all pass" crossover is, and, if it can be done passively. I was trying to read Linkwitz discussion, where he talks about Deulund and "filler drivers" but he mostly presented active circuits...

After reading through these web pages: http://www.silcom.com/~aludwig/Sysdes/Design_of_the_sound_system.htm (particularly here: http://www.silcom.com/~aludwig/Loudspeaker_construction.html#Panel_vibration_damping ) I want to do some further experiments, I just picked up a roll of 32# roofing felt and some vinyl floor tiles. I'm going to try some experiments using contact cement to attach inner and outer panels of the speaker enclosure to the roofing felt, and perhaps also compare one layer vs two layers of the roofing felt.

I'm guessing that binding with contact cement MAY be detrimental, reducing the de-coupling (similar to having two enclosure walls seperated by a layer of sand, somewhat, perhaps...).

EDIT: I would like to have ~ full BSC without padding the midrange, to keep ~ 88db sensitivity...