Dayton RS150S-8 + 27TBFC/G ala Jay_WJ

[sdclc126]

Hello Everyone,

After about three years lurking on this forum I have finally built my first set of serious loudspeakers, and they sound wonderful. Please refer to Jay_WJ’s thread as a primer:

Simulation Results: Dayton RS180 / Seas 27TBFC 2-way Bookshelf

Due to budget constraints and lack of tools and workspace I used the pre-built enclosures on this page:

http://www.supercellaudio.com/Pages/...nd%20parts.htm

I got them on eBay for substantially less than retail; they do not come with internal bracing, nor removable baffle or rear panel, so these are not suggested for a ground-up design. But they do come completely finished with a nice seamless black ash veneer and are a good value. I added rib bracing to the inside side panels, then a layer of PE vinyl sound damping sheets, then on top of that 3/4" Sonic Barrier. I haven't put the polyfill in yet because I'm too lazy to go to my storage locker to get it - but I will soon. I also had to seal the cutouts in the rear panel that were there for a terminal cup and port, neither of which I used. The internal volume is approx. 0.33 cu. Ft. before reducing for all the internal stuff – so say 0.30 final.

The 27TBFC/G was a near perfect drop-in save for the countersink being just a tad deep (gasket foam tape will fix that), plus I had to cut a little bit of wood to make more room for the wire leads.

The RS150S-8 midwoofers, as you can see in the photo (sorry I don't have the best camera) don’t quite fill up their countersinks, so I’m planning to fill that gap with gasket tape too – that’s a compromise (there are many) but it should limit any diffraction that’s already there.

After reading Jay’s thread I contacted him and asked him to design a crossover for me with the FRD Consortium tools he had used to model his “Modula” design with the RS 7” woofer. We went through a couple of iterations and the final one is shown in photo & diagram following this post. The goal here was simplicity and economics. Now, it is important to note that I have no measuring equipment and therefore the design is likely not optimized to my listening room and I have to trust that the resonance peak of the midwoofers has been reasonably tamed – if they are audibly ringing I can’t say as I have no frame of reference other than subjective listening, and they certainly sound terrific as they are.

Also note that these were intended from the beginning to be the upper two-thirds of a three-way which, when completed, will use the RS 8” woofers crossed at around 330 Hz. So the XO diagram shows the complete 3-way – just subtract the 8” circuit to get the current design (also subtract C1 & L1). At this time the speakers are mated with an <1 cu. ft. sub utilizing a Peerless 8” XLS (limited production and rare – purchased from John Krutke via eBay) driver with a 150 watt MCM plate amp – it’s not the greatest match-up because the Daytons should probably cross higher than the maximum of 160 Hz the amp can do, but again this is a temporary set-up until the bass units are completed. Even with the bass units I will most likely keep the sub in the system but very low – probably 60Hz or lower, but I’ll have to play around with that once the bass units are in place.

As for listening impressions, I will try to be as non-subjective as possible: very high resolution and detail, very low distortion. Therefore, highly accurate and true to the original. I think this is a great match of drivers with the end result being a very reasonably priced (< $300) and therefore very high value system. The 27TBFC/Gs are all they are cracked up to be and more, and the RS150S-8s are equally impressive for their price. I am getting to know my music collection (primarily classical) all over again and am hearing things I never heard before, especially impressive given that I have had a set of highly regarded Yamaha NS-670s for the past thirty years (dating myself here).

I would like to extend great thanks to JAY_WJ for his assistance on this project, and also to John Krutke of Zaph Audio for his driver tests, which led me to my selections for this speaker. And I would like to thank all of YOU out there on the forum for all the invaluable information I have gleaned over the past several years – without all of this I would not have been able to build these speakers. Are these it? No – these are however a wonderful starting point – in fact, Jay is working on a design with the TBFC/G mated to the Usher 8945P, apparently a very low distortion woofer that is possibly a SEAS and Scannie beater.

Of course comments, questions and critiques are welcome (that’s why we post!) but bear in mind I am not a designer and this project is far from perfect and has many compromises due to economics and other constraints as outlined above. Technical questions, especially ones regarding the crossover are best directed to Jay, who I will contact to let him know about this post.

Thanks again everyone!

[sdclc126]

Here's a pic of the XO.

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Here's the layout of the entire 3-way XO.

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Jay's FR graph #1.

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Last image.

[sdclc126]

Somebody humor me please.

[Hartono]

Hi there.....

looks like you really enjoyed the result .....hard to comment on that
happy listening.

Hartono

[Dave Bullet]

Congratulations!

It's very satisfying completing a pair of speakers and finding they are an improvement over a previous pair. Confirms your efforts were well worth it.

It must also be nice for Jay to have someone else build his design and confirm he made some good design decisions.

So many people treat commercial systems as a reference. I always get joy when people come over and listen to my system and go "wow, where did you get those speakers, I can't see any badges on them, who makes them".... then I tell them I did and the cost (cheap I mean!) and the jaws drop.... Always enjoyable.

Cheers,
David.

[sdclc126]

Hey thanks for the replies guys.

Dave - you are absolutely right - I played these speakers for my next-door neighbor and she was very impressed. To think you can get this kind of sound, even out of a less-than-optimized build, for a price that would probably get you slightly better than junk at a retail store, is very satisfying.

I'm very anxious to get the bass units completed - the 8" Dayton Reference woofers look gargantuan compared to the 6s, and should really open up the sound and fill out the bottom end quite nicely. They will either be side-firing floorstanders or will get built into a TV stand (a little creative endeavor here even if optimal sound is compromised), depending on what I finally decide to do decor-wise.

Yeah it's been great collaborating with Jay - this project would not have been possible otherwise. I have a feeling he's holding out to build with the Usher woofers, and who knows - I may beat him to that too!

[Dave Bullet]

Hi Softdome... just a few questions...

1. How did you arrive at the 3-way XO design (essentially a new crossover with all values changing in all 3 driver circuits) - was this part of Jay's original post (I can't find it)?

2. Are your FR graphs modelled or measured?

3. Did you have to take into account any band-pass gain with the midrange (possibly not relevant)?

4. Have you performed any off-axis measurements?

5. If you designed the 3-way xo tweaks, how did you create phase data between the woofer / mid? (ie. Hilbert transform on smoothed nearfield or actual measured via ground plane technique etc...)

6. Do you have any overall system impedance measurements?

Cheers,
Dave.