3-way with Vifa p13wh?

[johngalt47]

Does anyone have ideas about which woofer and tweeter to use with this mid? I don't listen to loud music; 85db is as loud as I like it and I usually listen in the 70s.

My main thing is getting the timbre correct. I like voices to sound as natural as possible. I just want the tone quality to sound real.

Overall, I want the low end to get to 40hz flat. The high end doesn't need to go way out there since my hearing is aging.

I have several of the mids so I don't need to buy any of those. I figure to spend about $1,000 for the woofers, tweeters and crossover components.

[Thooms]

I've been looking at a similar issue johngalt47.

In terms of value for money, the woofer which caught my eye was the Seas ER18RNX. In particular, it looks to have a nice clean low end, which would be handy for a 3 way methinks.

Tweeterwise, a Scan Speak D2608 or Vifa XT25 are the two which I am looking at.

I've picked these on the based on good distortion performance and good response curves (based on data from Zaph's excellent page). As a bonus, they aren't insanely expensive either.

http://zaphaudio.com/

Edit: As you have a bit of a bigger budget and you haven't stipulated if you are shooting for a particular volume, the Scan Speak drivers are reputed to have amazing low end performance. Maybe something like an 18W/8530 if your budget will go that far?

[johngalt47]

The volume can be as large as it needs to be.

I have a pair of ZD5 speakers which use the XT25. The only issue I have is that the crossover is quite complex but that may be because it is time aligned electrically.

[Thooms]

I noticed the impedance seems fairly low too. Perhaps the D2608 would be a better choice? It's nice to have a change with the freedom buying new stuff brings

I haven't looked at bigger speakers than 180mm size - maybe a Scan Speak 21W size driver could be a good option if you aren't restricted in cabinet size?

[johngalt47]

For tweeters, I was looking at Zaph's tests and it appears that the following might also work:

Peerless 810921
SB Acoustics SB29RDC
Seas 27TDFC
Viga DQ25SC16-04

Previously I had considered the Seas L26ROY but Jed says that the Scan Speak 26W/8867T has lower distortion. They are really expensive but I want the lowest distortion possible. I also thought about the JBL pro woofers like the 2226H.

[Thooms]

I believe the Peerless unit you mention is the same as the Scan Speak one I was talking about. Sounds like it should be a fantastic system with components like these...

[Curt C]

Right, the Peerless HDS tweeter is now the SS D2608/9130 discovery tweeter.
It’s a good choice, and I’m considering it for a 3 way I’ve got on the drawing board now. -Don’t forget to consider the Dayton RS28F, and don’t let the $40.00 price tag fool you. This Usher sourced tweeter is top drawer in every respect, including class leading low distortion. Crossovers as low as 1K are possible, although not necessary with the P13. One can easily cross low order, and/or partially fill in the dip in response caused by the cone edge resonance on the P13.

FWIW, the SB29RNX looks very good in my initial testing, and will make an f3 of 40 Hz in a reasonably sized box. These are built like brick outhouses, and just ooze quality construction. Fit and finish are excellent, and the four I have all measured quite closely.

C

[augerpro]

I'll second (third? fourth?) the SS 9130 tweeter. Very nice.

Curt, how do you like the RS28F over the aluminum version?

[johngalt47]

Curt,
Thanks for the recommendations. The SB29RNX looks like it will fit into a 33 liter sealed box and it is less than half the cost of the SS I previously mentioned.

[Curt C]

Curt, how do you like the RS28F over the aluminum version?

The subtleties of good tweeters are unfortunately somewhat lost on my old ears. From what I can hear, the F is a bit more pleasing to my ear, but they are very close. -My companion in crime, Wayne, on the other hand, can still hear a flea fart, and he prefers the F over the A. I don’t recall we ever discussed exactly why, though.

Curt,
Thanks for the recommendations. The SB29RNX looks like it will fit into a 33 liter sealed box and it is less than half the cost of the SS I previously mentioned.

John, don’t forget to compensate for the series resistance of the woofer crossover, volume displaced by the woofer, voice coil heating, etc. in your calculations. I’m thinking something like 40 to 48 liters will be optimum for a sealed enclosure. Another possibility: It also models well in a classic tapered transmission line for a lower f3 in a somehat larger box.

C

[johngalt47]

Thanks again, Curt!

I'm glad you mentioned a transmission line since I've been wanting to build one. Which taper do you think would work well? Something simple like a 2:1 or 3:1 or more than that? I can access Martin King's alignment tables if necessary.

[Curt C]

Acutally, I've been more enamored with higher taper ratio’s as of late, especially considering the low fs of this driver. –The lower the taper ratio, the longer the line, and the closer it is to ¼ wl of fs. ¼ wl at 21 Hz is over 13 feet, and an enclosure that size is just a trifle cumbersome... 8O

A single fold 72” long TL with a 25:1 taper and a large end area of 2.5 Sd models quite well, and is reasonably compact at about 65 liters internal volume. Folded in half, it is 36” tall internally, so it is a reasonable size for a floor stander. Woofer offset was 14.4” from the big end, and stuffed with 1lb/ft^2 in the front half of the line.
–Doing a quick calculation, the big end will have an area of 145”^2 and the terminus 5.8”^2. Yes, the terminus is a bit small, but fired out the rear lower corner of the enclosure I doubt any terminus noise will be heard at sane SPL’s. I haven't built it yet, but it will be the basis for a couple of 3 way designs planned for this summer...

C

SB29RNX modeled response:

[johngalt47]

Do you leave the mid and tweeter exposed to the internal volume or enclose them in their own chamber?

[Curt C]

Any midrange speaker that is not closed backed or otherwise sealed must not share the woofers enclosure.

My thoughts are to build a separate, integrated midrange enclosure above the woofer enclosure. The vast majority of tweeters are sealed and it is perfectly fine to mount these in the woofer or mid enclosure. Don't skimp on the midrange enclosure volume as too small of an enclosure will be detrimental to the sound quality. It can be difficult to stuff it sufficiently to ameliorate the reflected energy/standing waves without making the result sound lifeless...

See my Maverick design at my site for an enclosure example...

C

[jwr]

To be honest I don't really see the point in using the P13WH as midrange with a 7" bass driver. I tried it in such a small vifa 3 way, and the midrange is ok, but I would choose something else next time. If you really want to use the P13, I would match it up with a 1" dome tweeter for a crossover around 2kHz to 2.5kHz, because it won't be at its best any higher than that.

If you don't play it loud, a good 7" in a 2-way will probably be a good match for your needs. Just about any of the Seas 7" drivers would be good candidates in that case.

[johngalt47]

I have 7 or 8 P13Wh drivers lying around looking for a home.
I want to incorporate at least two of them into a 3-way design.
I'm trying to figure out which design to use.

[jwr]

Hi John. Am I correct to assume that you do not have measurement equipment and software needed for crossover design?

If you wanted to design your own crossover, it would be one thing to pick a Seas CA18 and and 1" dome and start measuring and modelling for crossover design. However in my opinion, it would be far from easy to get a better result than from one of the 2-ways designs already developed, eg SR-71 kit or similar. For the 3-way system, you will find a lot of padding will be needed to get the sensitivity of P13 down far enough to work in the 3 way sytem.

Did you consider building a MTM using two of the P13s? There is the Ariel and ME2 design by Lynn Olsen, that could be a starting point for the crossover design.

[johngalt47]

I have all the equipment I need to measure the speakers. I have Soundeasy, mic, etc. I also have WT3 and have obtained the T/S params. However I have not measured the speakers as a system.

I've tried playing around with Jeff Bagby's PCD also.

Yes, I've tried to figure out a MTM as well.

I have the Loudspeaker Cookbook, Building speakers 201, etc.

I've tried crossover modeling using Speaker Builder also.

I just have not put everything together yet in order to design the whole kit and caboodle.

I've thought of using JBL's 2226H because it is fairly sensitive and from what I've heard has low distortion.

[jwr]

John, I'm personally not a fan of 3-ways with 10" or 12" drivers, because I think they are very hard to do well. I'd be inclined to stay with nothing bigger than 8" woofer. I think the smaller woofer will allow a more integrated sound as it allows you to place the drivers closer together and use a higher crossover point. Crossover at 500Hz or higher is better because it avoids using very large passive components that will mess up the bass alignment in most cases. With that in mind I'd be looking for an 8" midbass driver with 90dB or more sensitivity. The Peerless 830869 looks like a reasonably priced option. Its just a suggest for my 0.02 worth.

[johngalt47]

The best solution?

How about if I use active crossovers?

[jwr]

Active crossovers can be helpful if you like to use a low crossover frequency, especially for subwoofers. Apart from that I Don't think that going active has such big advantages for a home audio system at the power level you are looking at (my opinion only!). So unless you need to use very low xo frequency such as 300Hz or lower, I think it is just adding compexity for very little benefit. For a low XO frequency for the subwoofers, even using a active xover it still won't be straightforward to get the same integrated sound as a simple 2-way speaker.

The major disadvantage I see is that it is much more time consuming to develop an analogue active crossover system. Whereas a passive crossover it is very simple to tweak component values, then measure or listen until you get the result that you like. Simplistic hard-configured analogue active crossovers just don't have sufficient flexibility for proper system design. Digital crossovers are wonderful in theory, but may not be live up to the expectations in terms of pratical implementations that are available to the hobbyist. However, if you enjoy twiddling with digital techology that can be an interesting hobby in itself.

[johngalt47]

Replying to jwr:

Have you looked at the 10" Seas L26ROY? It has low distortion, can cross over pretty high and is fairly sensitive.