5" Reference Series *PIC*

[tomzarbo]

Has anyone used the Dayton 295-370 non-shielded reference series woofer in a project yet? I think they're relatively new, just wondering how they sounded if anyone has done a project using them. I'm considering an MTM with them and possibly one of the dayton tweeters, and possibly a built in powered sub...
any suggestions?

Thanks in advance,
TomZ

[tedwilt]

> I'm
> considering an MTM with them and possibly

These have no response charts available yet so you are buying in the dark plus the 4 ohm impedance eliminates using 2 in parallel.

[shawn_a]

I would think that it has the same sonic characteristics as the shielded 8Ω unit. These new 4Ω puppies have just been introduced and a few were given away as door prizes at DIY Dayton this year. As for Ted's concern about not being able to wire them in parallel, I don't think that's an issue. Look at Curt's TriTrix MTM. Works pretty good from all indications.

shawn

[Pete Schumacher ®]

> These have no response charts available yet
> so you are buying in the dark plus the 4 ohm
> impedance eliminates using 2 in parallel.

You can always wire them in series for a 3dB more sensitive version instead of 6dB vs the single 8 Ohm version.

[tedwilt]

> You can always wire them in series for a 3dB
> more sensitive version instead of 6dB vs the
> single 8 Ohm version.

Pete,
Here is my take on the subject based on years of reading articles but no personal research.
Depends on the use for the driver. If you know you are only going to use one driver and if 4 ohm is ok for your amp, use the 4 ohm version to get 3 dB more output. Likewise if you plan to use 2 drivers and your amp will not work with 4 ohm, you can run two 4 ohms in series although the literature generally suggests that this will accentuate any anomalies in the frequency response. Parallel operation is supposed to smooth frequency response, especally if the drivers are not identical. I would never consider using one 5" driver in a system or an amplifier that will not handle 4 ohm loads; therefore, the 8 ohm version would be my preference. We both agree that 2 drivers will give about 3 dB greater output due to increased radiation surface. If we use 8 ohm versions, we will get an additional 3 dB by going to the 4 ohm combined impedance. The 4 ohm version will decrease output by 3 dB by going to 8 ohm. My head hurts now. LOL

[tedwilt]

After comparing the two versions, I conclude they are not the same. The 4 ohm version is less than half the Re of the 8 ohm, longer xmax and lower resonance. The 4 ohm version might be a little better and might be satisfactory by itself if we could just see the graphs.

[Pete Schumacher ®]

> After comparing the two versions, I conclude
> they are not the same. The 4 ohm version is
> less than half the Re of the 8 ohm, longer
> xmax and lower resonance. The 4 ohm version
> might be a little better and might be
> satisfactory by itself if we could just see
> the graphs.

If you check out Zaph's graphs of the RS150-8 and RS150-4, you will see they are almost identical except shifted in sensitivity. I'd bet the RS125s behave similarly.

[darrenk]

Very astute conclusion you've reached. Yes, they are not the same... one is an 8 ohm version and one is a 4 ohm version. By definition, the Re is going to be different between the two. The resonance is probably slightly different due to the extra mass of a longer coil on the 4 ohm version, but not significantly so.

It appears that the "soft parts" of the two drivers are essentially the same, so the overall response of the two drivers should be very close as well. The 4 ohm version might have slightly more extension at the top end due its lower voice coil inductance.

All-in-all, if you like the performance of the 8 ohm version, then the 4 ohm version should also probably be to your liking.

But what do I know....

Darren

> After comparing the two versions, I conclude
> they are not the same. The 4 ohm version is
> less than half the Re of the 8 ohm, longer
> xmax and lower resonance. The 4 ohm version
> might be a little better and might be
> satisfactory by itself if we could just see
> the graphs.

[tedwilt]

> Very astute conclusion you've reached. Yes,
> they are not the same... one is an 8 ohm
> version and one is a 4 ohm version. By
> definition, the Re is going to be different
> between the two. The resonance is probably
> slightly different due to the extra mass of
> a longer coil on the 4 ohm version, but not
> significantly so.

> It appears that the "soft parts"
> of the two drivers are essentially the same,
> so the overall response of the two drivers
> should be very close as well. The 4 ohm
> version might have slightly more extension
> at the top end due its lower voice coil
> inductance.

RS125S-8 Specifications: *Le: .65 mH *Znom: 8 ohms *Re: 6.3 ohms *Frequency range: 70-4,000 Hz *Fs: 72 Hz *SPL: 86.5 dB 2.83V/1m *Qms: 2.50 *Qes: .54 *Qts: .44 *Xmax: 2.8 mm

RS125S-4 Specifications: *Le: .34 mH *Impedance: 4 ohms *Re: 2.9 ohms *Frequency range: 65-4,500 Hz *Fs: 65 Hz *SPL: 91 dB 2.83V/1m *Vas: .12 cu. ft. *Qms: 3.39 *Qes: .61 *Qts: .52 *Xmax: 4 mm

If these two drivers have identical response, I will give you all of my poker winnings for last week, but don't call up your broker to spend the money just yet. LOL

[curt_c]

> If these two drivers have identical
> response, I will give you all of my poker
> winnings for last week, but don't call up
> your broker to spend the money just yet. LOL

The T/S parameters generally describe the response of the driver in the compliance controlled region. The response of the driver in the mass controlled region (above resonance) will be more dependent on things that remained the same: The cone, surround and spider.

C