woofer choice for wmtmw design

smigza

Member
2012-08-25 5:40 am
Hi all,

I am contemplating upgrading my front speakers with a diy wmtmw design:rolleyes: consisting of xt25 tweeter, 2x peerless 830986 midrange and 2x peerless 830657 as the bass driver. I have simulated in visaton boxsim successfully.

The crossover frequencies are 500hz and 2.6khz

The bass drivers are 6.5 inch and have been chosen due to price restrictions. They are stamped frame however can play below 40hz f3 with the right volume and port selection. The distortion profile below 450 hz is similar to silver flute woofer. The woofers are paper cone from SDS product line

There are a number peerless drivers which are a bit smaller at 5.5 inch hovever they have a cast Frame and a better distortion profile. With the right port and enclosure these drivers can play down to 60hz f3. The driver will be $10-15 more expensive than the 830657. The cone will either be fiberglass or polypropylene from HDS product family. They have the same sensitivity as the 830657.

My question is how important is the bass driver for overall sq, is it worth going with the smaller driver for the sacrifice of low end for improved distortion, transient response and a cast frame. Also I hear paper cones sound best; will a fiberglass or polypropylene cone have a significantly different sound signature than paper?

Thanks,

Steve
 

smigza

Member
2012-08-25 5:40 am
Thanks for your responses so far.

I have modelled the woofer in boxsim and winisd seems to model ok for a ported enclosure. Someone on parts express has recommended the dimensions for a ported enclosure as well. Unless a ported design will give crappy bass?
 
My question is how important is the bass driver for overall sq, is it worth going with the smaller driver for the sacrifice of low end for improved distortion, transient response and a cast frame.

Stay with the Peerless SDS 164 drivers. Going smaller is no option, you will not gain anything. The equal sized drivers from the Nomex and PPB line offer lower distortions and more Xmax, but they actually do not outperform the SDS regarding bass performance at a given transient response!
 

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  • Peerless SDS 164 (830657).jpg
    Peerless SDS 164 (830657).jpg
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  • Peerless HDS PPB 164 (830874).jpg
    Peerless HDS PPB 164 (830874).jpg
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  • Peerless HDS Nomex 164 (830875).jpg
    Peerless HDS Nomex 164 (830875).jpg
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smigza

Member
2012-08-25 5:40 am
Thanks for your post Dissi,

I guess my main concern is the value added to sound quality below 500hz by going from SDS to HDS, eg will there be a significant difference between the 6.5 inch SDS and HDS drivers in this frequency range and could the pressed steel frame of the SDS driver have a resonant mode which will be audible in this range as well? Or is the whole resonance thing only an issue when throwing big power levels into the driver?
 
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I think the issue would be that the drivers would bottom-out to quickly - if they are not in a sealed box.

A common problem when using drivers intended for sealed boxes in vented boxes.



Thanks for your responses so far.

I have modelled the woofer in boxsim and winisd seems to model ok for a ported enclosure. Someone on parts express has recommended the dimensions for a ported enclosure as well. Unless a ported design will give crappy bass?
 
smigza,
do you use a subwoofer, is this a HT setup? If Yes, I warmly recommend the sealed arrangement! Even without a sub, sealed has better bass quality and quite good extension.

2x 6,5" woofers don't play very low AND loud in any arrangement. They are fine for music but for movies they need a sub. Many people are looking at amplitude responsion curve's linearity, but forget how excursion, group delay and distortion behave.
 
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AllenB

Moderator
Paid Member
2008-10-18 11:31 am
I guess my main concern is the value added to sound quality below 500hz by going from SDS to HDS
The 200-500Hz region is worthwhile getting right. I find the room can play a significant part in messing this region up and the design of the speaker plays a role in that. This is probably more significant here than a choice of cone material, or even driver size.
Or is the whole resonance thing only an issue when throwing big power levels into the driver?
I'm sure we're all familiar with the sound of a resonance turning from a ringing into a buzzing as power levels rise and the loose part in question begins reaching the end of its travel. Notwithstanding this a resonance is more likely to be consistent with the power applied.

If you find something, first try equalising it (through the crossover or otherwise).
 
Smigza, better than the 830657 are the SDS-160F25PR01-08.

Better linear excursion then the 830875, tho as others have said would not give the best impulse response and higher distortion. Is a nice driver $$. Building a MLTL using these and tests prove bass is rather impressive with the low end around 30 (actively crossed @27), hearing is believing. Midrange to 2400 once tamed (and breakup peak around 4300), mids are even quite nice. Flip side of this coin is the rather high VAS for it's size which calls for a larger than normal box. None the less anything from 1.1-1.6ft^3 in a normal BR will work to get you into the mid 30's at least. Acoustic suspension that would be Q .707 ~.33ft^3 with an f3 of 80, f10 of 46Hz

I'd say 2/ speaker would be a minimum (or MAX if in an apt. ;)
4 work nicely. No need for a sub