Design review - comments on driver selection

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Hi folks,

I am planning to build a 3-way speaker, and would like to hear you guys what you think of my driver choices.

Tweeter:
Scanspeak D2905/970000

Mid:
Peerless HDS 164

Bass:
2 x Peerless SLS 213. Each driver will have a sealed 25 liter box, and they will be wired in parallel. Not a "nice" load of the amp, but it can handle it.

X-over will be 2nd order at around 200- 250Hz and 2kHz, respectively.
Baffle step will be -3 dB at around 200 Hz with my planned 25 cm wide enclosure. (Unless my math is wrong with "The Edge".)
The parallelled bass drivers will have a higher sensitivity than the rest, but they shall be able to play BASS even with the baffle step loss, within the limits of speaker cabinets that have decent W.A.F. ;)


What do you folks think?
Jennice
 
I have no problem with your driver selection at all its just the scan 97, is that not a bit OTT for the peerless HDS series? I have used the HDS w phase plug and both the 95 and 97 from scan. Yes the 97 is worth the extra pennies but im not sure if its worth it as much, if you are not pairing it with another top notch woofer. If you are considering the 97 then money might not be that much of a worry. I would suggest improving the midrange driver or using a tweeter thats not as good just because I think that extra money spent on the scan wont be as well spent here then it would be in another application. Id suggest a SEAS excel or scan driver, I have always wanted to try the kevlar 6.5" its meant to have a very good midrange. You are using measuring software to design this I hope?

Another thing, I would take the scan a touch higher to say 2.5khz the peerless can definately handle a higher xover. Two SLS and a HDS will have the ability to go loud id play it safe and keep the tweeter xover a bit higher for these "loud" times.
 
Sounds nice overall, but you're overestimating bass sensitivity. With baffle-step compensation happening both in the woofers and the mids, I don't think you should expect more than 86-88dB/w/m sensitivity from the system.

My SLS 8's measured at 84.5dB/w/m, with a Qts of 0.596 and an Fs of 43.7Hz, as opposed to the published 87.2/ 0.54/36.5Hz. While that may not be typical, it is consistent with the deviations from published parameters that Bob Brines found in the CSX woofers he used in the Peerless Pipes.
 
Pallas,

With a 25 cm wide cabinet, where do you get the baffle step to have -3dB?



5element,

Englich isn't native to me, but I trust that "OTT" means "Over The Top", as meaning: Unnecesarrily expensive. Am I right?

Which scanspeak driver would you suggest for this project.
Remember it will need the size to cope with 200 Hz.

When I did the math, a HDS134 could do the job, but when rooling off with 12 dB/oct., it would run into excursion limits faster than the filter could cut it off. Therefore I needed the HDS 164.

If you have something in mind with similar size, please let me know ASAP (as I have to make ordering desitions really soon).

Jennice
 
Yes OTT means over the top you are exactly right. I think the 97 is a fantastic tweeter but the 95 will probably suit the application better. If you are happy to buy the 97 then go right ahead I would not want to discourage you.

I am surprised at the excursion limits imposed buy the HDS134, I have used the seas excel W15CY001 in a sealed box with a 12dB electrical = 24dB acoustic at 150hz, excursion was never a problem there.

In a 1.6litre sealed cabinet (OK i know small) with a 4th order acoustic slope the W15 will give sound pressures of 110db before the driver breaks due to mechanical failure. It will fail at about 105 thermally but thats another matter entirely.

With a HDS164 you will achieve 117dB before mechanical failure in its passband with about 108dB thermally. Remember this is at 150hz too, 4th order linkwitz acoustic slopes using 2nd order eletrical filters.

Bottom line - dont worry about the midrange driver.

Over in the UK we get a nice deal on scan97's they are only a small amount more costly then the 95, so over here I would suggest getting the 97's. If where you live you can get 97's for a small amount more then get the 97's. Here a pair of 95's cost £134, a pair of 97's cost £160, as you can see not that much more.

I have not used a pair of seas tweeters yet but I would like to, I know that the 95 sounds really nice with the HDS164 so would suggest using the 95, if you cant get the 97 cheap. On the other hand the seas 27TDFC might also be a good choice, I have not listened to this so I cannot compare it to the 95.

If you want to go the other route of upgrading the midrange driver, then its your choice entirely what you go for. You wont go wrong with the W15CY001 providing you can deal with its break up at 8k. I think the kevlar scan would also sound nice, all I have read is praise about its midrange the 18W-8546-00. Another thought is the CA18RLY and CA15RLY from seas, these are highly praised drivers too, but im not sure if they will compete with the excels or the scan.
 
5th, I'd be interested in your comments on the HDS drivers. Are they not as detailed, clear, etc as the pricier drivers?

I'm asking because I'm getting ready to place an order for HDS 134's and 164's, along with either the 9500 or 9700 for a dipole I'm working up. Good timing with this thread.

Thanks,

Paul
 
paulhfx said:
5th, I'd be interested in your comments on the HDS drivers. Are they not as detailed, clear, etc as the pricier drivers?

I'm asking because I'm getting ready to place an order for HDS 134's and 164's, along with either the 9500 or 9700 for a dipole I'm working up. Good timing with this thread.

Thanks,

Paul

I find that the HDS doesnt sound a clear as the metal coned excel driver however this may be the poly cone talking and not the actual driver. For the money however the HDS does sound very good and they go very loud/handle power, extremely well. If you like to thrash your cones and love bass then you wont go wrong with the HDS, atleast the 6.5". But if you are after that detailed clean clear sound then a metal cone is more your thing.

I would like to compare the SEAS poly excel midrange to the W15 mag cone in the same application to see what the difference is, but I dont think its worth spending all that money on a pair of M15's if im happy with the W15's!

The large xmax and highish Qts of the HDS series (im thinking the 6.5" here) make sense when thinking about an open baffle though too. You could also consider the metal cones SEAS standard range.

Remember you have the drivers in the loudspeaker but you also have the application of the drivers and this is just as important. OK if you get two very low distortion drivers and make a hash of the xover you will still have a low distortion speaker but thats not the point.

Jennice said:
Thanks for the suggestions. :)

However, I have the chance to get my hands on (new!) HDS164 for about £14 each, as a friend bought too many. Compared to the scanspeak in shops, that's about 10 times cheaper. I find that VERY hard to resist. :D

Jennice

In that case go for the HDS! £14 each :D its worth using them just to see what they are like. If you want to upgrade later then you can and put the HDS in a small two way for another room.
 
Hello

I am working on a 3 way project with this:

Old cabinet from B&W DM640
1 SS9700
1 SS15W8530K00
2 old basses from DM640

2 order crossover @ 250Hz and 2200Khz

The cabinet haves 7Liter for the midbass and 27Liter for the 2 bass.

Have any off you suggestions for other cossoverfrequenies /Xover?

What do you think about 2 Perless SLS 8" in paralel + SS9700 and 1 SS 15W8530K00??

Jennice how is going with your project?

Kim
 
kim,

Bringing the old thread back to life, eh? :)

It took quite a while before my project proceeded to take shape.

However, I ended up with a design which I'm very pleased with (although the folter needs some changes).

I used the ss 970k tweeter, a HDS134 mid, and 2 x SLS8 (sealed enclosure).
Quite like your setup, kim, except that my SLS's have about 22 liters each, which was the lowest I dared to go.

The mid has a small rise I want to tame, but overall, they make my DM630's (the first series) sound boring. The treble and imaging is clases better, and the bass almost hurts. It also goes lower than the DM630's in their bass reflex.
I made my boxes of 22mm MDF, and with a divider between each SLS (effectively making 2 individual bass-enclosures), and a seperate enclosure serction for the mid/treble.

Anyone want to buy a used pair or B&W speakers? :D

Jennice
 
Hi Kim,

I haven't tried to build much with bass-reflex, but generally, a BR plays with a different roll-off at the expense of precision.
As for the X-over, I will have to piece it together myself, as my PC with the details crashed recently, talking the data and my programs with it.

I placed the lower x-over at around 220 Hz, roughly suiting the baffle step frequency. Thus the BS effect is pretty much cancelled as the SLS-8 is just about the same sensitivity as my HDS-134, and I'm using 2 x SLS-8.
The design isn't "over-bass"'ed, despite the 2 SLS's. They play DEEEEEP, hard and precise bass, though, compared to the DM630 I used earlier. (Even when the BR port was closed on them).

My tweeter is attenuated, but that doesn't come as a surprise. I was surprised, however, that the mid wouldn't hurt being lower.
Therefore I don't think your lower mid sensitivity will be a major problem, but I sugest you get a second oppinion on that.

Jennice
 
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