Daline with Vifa

[patstevens]

I have recently retired and moved to Spain. My present LS ate Webb TL´s which were made about 4 years ago. Our house in Spain is smaller (the SAF is not high for large TL) and I would like to have a decent DD 5.1 system - with emphasis on CD´s etc.
I love the daline for its quality bass response (especially with the KEF 139!!!); it would seem that a Vifa PW17 is a good place to start for the main driver in a smaller design. I would also like to keep the same ´sound´in the smaller speakers by using either more PW17 or a very similar sounding smaller Vifa driver in a smaller cabinet - another TL would be fine.

Can anyone please point me in the right direction for any of these DIY versions? Any advice would be appreciated.

Many thanks

Pat Stevens

 

[GM]

What's your performance goals, i.e. average SPL/listening distance, XO point to the LFE, power available, etc.?

Anyway, if by PW17 you mean the P17WJ-00-08, then based on some measured specs of several units, Qts, Vas is a way too high/low for a proper Daline alignment.

They are real close to a T/S max flat ML-TL natural cab alignment (Vb = Vas, Fb = Fs) though: 30.22" long with a CSA of 46.017", driver 11.5" down from the top and 2.5" dia. x 4.5" long vent near the bottom, ergo close to ideal for an HT's LFE's 80Hz XO. All dims are inside (i.d.) with minimal stuffing to suit and 19mm Baltic Birch or equal (min) construction recommended.

GM

 

[patstevens]

Hi,

Many thanks for your reply. I will have to do some work on what the parameters mean. From what you say I may have to be content with a simple TL. Back to the drawing board!!

Thanks again

Pat Stevens

 

[jackinnj]

take a look:
http://www.tech-diy.com/LS_Articles.htm

 

[patstevens]

Thabks

Will look at and consider

Pat Stevens

 

[paulspencer]

You could use the P13 for your surround speakers as it works nicely for smaller boxes, although there is significantly less bass to speak of. Or you could use the P13 all around if you only want the bass to get down to 80 Hz and then cross to a sub. The midrange is a bit more tame.

 

[patstevens]

Hi,

Thank you for all your replies and help.

I do like the idea of having all the speakers with the same driver. Having thought about it, I am considering a pair of ME2 then small ported rear/centre speakers - but all with the same drivers.

Thanks again

Pat Stevens

 

[Dave Jones]

You could use the P13 for your surround speakers as it works nicely for smaller boxes, although there is significantly less bass to speak of. Or you could use the P13 all around if you only want the bass to get down to 80 Hz and then cross to a sub. The midrange is a bit more tame.

The P13 won't go that low in a sealed box. Based on limited experience, I have reservations about using a ported system and a sub.

 

[Dave Jones]

Hi,

Many thanks for your reply. I will have to do some work on what the parameters mean. From what you say I may have to be content with a simple TL. Back to the drawing board!!

Thanks again

Pat Stevens

The MLTL is not a "simple TL". It's a tall and skinny ported system that has some of the characteristics of a "vented" system and some of the characteristics of a TL.

Concerning the T/S parameters...


Fs is the fundamental resonance frequency of the speaker in free air. Other things being equal (which they never are ), low Fs is a good thing in woofers and mid/bass drivers.

Vas is a measure of acoustic compliance. It is the size of a sealed box that would raise the fundamental resonant frequency of the system to sqrt(2)*Fs. Other things being equal, you have to put high Vas speakers in large boxes and low Vas speakers in small boxes.

Qts is a measure of how resonant the speaker is. High Qts speakers are more resonant (less damped) than low Qts speakers. Other things being equal, high Qts speakers have to go in larger boxes, else they become too resonant ("boomy").

 

[madinoz]

At the risk of offending.
My experience with the P17-wj hasn't been a positive one.
I thought the bass was very "tubby" (not tubey!).
I don't know if anyone else would share this point of view or whether it's just me.
I have have good experiences with the Peerless HDS range and would recommend these as they have a multi-layer poly/foam construction making them stiffer than the P17. Okay, so they aren't high end but then again they are around the same price as the P17's and sound far better (to my ears).
Could be used in a small sealed box if mated to a subwoofer.
I would suggest that the voicing between the 5.5 inch and the 6.5 inch units would be similar (anyone out there used both???)
The 5.5 inch units have a nice midrange but would have no bass in a sealed box.

 

[paulspencer]

The P13 won't go that low in a sealed box. Based on limited experience, I have reservations about using a ported system and a sub.

True, it would need a vented box. Vented boxes can be used in satelites quite well. Here's a good article on one way to do it

I have have good experiences with the Peerless HDS range and would recommend these as they have a multi-layer poly/foam construction making them stiffer than the P17. Okay, so they aren't high end but then again they are around the same price as the P17's and sound far better (to my ears).

Sometimes I think words like "high end" get in the way of making good decisions. If something is "high end" or not often depends on who you ask. In some applications I've found my speakers more enjoyable than other more reputedly "high end" speakers. It comes down to what suits you most.

I have heard HDS and Vifa drivers, Scan Speak and Seas Excel. Often how they are used is more important than the drivers themselves. I'd say the Peerless HDS drivers are probably slightly better than Vifa overall, for a slightly higher cost. But I've also heard Seas Excel and Vifa P17 side by side and had a hard time deciding which I liked best, despite the psychological impact of expecting more from the Excel drivers.

 

[Dave Jones]

True, it would need a vented box. Vented boxes can be used in satelites quite well. Here's a good article on one way to do it

I didn't find any one place in that article that clearly stated the problem to be solved. But the jist of it seemed to be that QB5 alignment has better power handling capacity than other ported alignments (and sealed boxes are worse yet in that respect). Strike one (for some applications) is that you must use a 2nd order high pass on the QB5 satelites; you can't just let the satelites run free. And is power-handling the only problem with using a ported system with a sub? How about the phase response in the crossover range? Perhaps I was wrong, but I kind of thought phase interaction might have been one reason why my Locust I's sounded so bad when matched with a sub. When I plugged the ports, they matched up just fine. But then, I need very little power handling in my office.

 

[madinoz]

I have read before that this alignment (QB5) does have a better power handling than other ported systems which have a larger box to Vas ratio. There is another benefit in that if the alignment is done very carefully and the driver has a suitable Qts, the roll off below the port tuning point can have similar characteristics to a (Higher Qt) sealed box alignment.
This will (if it is acheived in practice), allow easier integration eith a sub woofer as well as providing the obvious advantages of higher power handling and better bass extension of sealed boxes.

 

[paulspencer]

I didn't find any one place in that article that clearly stated the problem to be solved.

It is here:

So, in this area of compromise, there has to be a solution that will provide a reasonable SPL with minimal excursion created distortion.

So, in a nutshell, he proposes a way to make small satelite speakers that can cross to a sub with low distortion and higher output than you would normally achieve with a sealed box.

The solution is to introduce a bump in the response and filter it out with a salen key. A highpass filter is also required. As shown:

An externally hosted image should be here but it was not working when we last tested it.

Green line is after the filter is applied.

If you play around with this in WinISD you will notice that the max output goes up dramatically. He shows an example of the Vifa P17 achieving 16.8 dB more max output.

This will (if it is acheived in practice), allow easier integration eith a sub woofer as well as providing the obvious advantages of higher power handling and better bass extension of sealed boxes.

No, vented boxes have higher power handling and better bass extension. Sealed boxes have a shallower rolloff but a much higher F3. Their power handling will usually only be greater at a point that is too low to have much useable output.

It surprises me how much negativity exists in thinking about vented boxes. I suspect problems are often more related to application, rather than shortcomings in the vented alignments.