Using the HiVi D8.8 speaker - help, advice, tips

[VitekM]

Hello.
I have a pair of HiVi D8.8 speakers and I'm thinking about how to use them meaningfully.



I came across the Tarkus project and its variant with HiVi on Paul Carmody's website.

https://sites.google.com/site/undefinition/floorstanding-speakers/tarkus

The Techtalk Parts Express link provided is unfortunately not working (and the registration on the TT forum, where I primarily wanted to ask questions, does not work, sad story). Does anyone have any further information on this version of the project? I am mainly interested in the crossover diagram and the plan with the dimensions of the modified speakers. The photos show a change in the shape of the enclosure in the bass section, the use of a HiVi D6.8 as a mid-bass and a ringradiator tweeter.

I have three options in my head so far
- the use of Modula MT (HiVi D6.8-SB Acoustics SB26STAC-C000-4) or the HiVi Swans 2.2-A kit and its extension by a third band (the above-mentioned Tarkus clone could also have followed a similar path).
- 3 way using coaxial SICA 5.5 C 1.5 P / TangBand W4-2315 or possibly SEAS (inspired by Adterion, Driva, Minerva, Monoculus, SBS.1 …) and stick to manufacturer recommended volume.
- buy older Dynaudio loudspeakers (Audience, Focus) and make a third band for them - an active woofer.

Nothing is decided. That's why I'm asking for your tips for a proven DIY with HiVi D8.8.

I'm from Europe. That's why, if you have shopping tips, please only from the EU. I have no reason to pay duty and taxes for imports from third countries.

[duvixan]

I messaged mattp on TT, will keep you posted

[VitekM]

Thank you.

[JonMarsh]

This is a curious part. I've used the D6.8 before in a few systems a long, time ago. The D8.8 is described as a subwoofer, but the Xmax is listed as 7.5mm. Resonance issue with the cone do seem to preclude it as a more wide band kind of mid woofer, compared with the D6.8.







The impedance glitch at 400Hz correlates well with the irregularities in frequency response. This means energy storage and breakup of a sort in the cone/suspension/voice coil system.

Perhaps I didn't have enough coffee this AM (only one cup!) and am lacking imagination in how this would slot in to a design that originally has a 10" woofer, and a 6.5" midrange.

Now, that Peerless mid and the DX25 tweeter are still available; if I was going to revisit and tweak that design, I'd be looking at a more modern woofer design at least, if 10", the RSS265HF, which is available from European distributors, or if downsizing, the RSS210HF-4, also available. Both have a very stiff well designed cone and first breakup far above 1kHz. nearly 4kHz in the case of the RSS210HF.

Of course, you're not me, you have your own needs and goals. Since you're looking for a "proven" design, that means (to me) one that you don't have to do any development work on. The Targus employs a 2nd order crossover at 400Hz, which is pushing your luck with the D8.8, IMO. Something to be cogent of...

[VitekM]

Thank you for your feedback.

If I wanted to build a Tarkus and wanted to somehow modernize it, I would take your recommendation. Of course, I can choose from a sea of other DIY constructions. But I already have HiVi D8.8 speakers at home and I'm looking for a use for them.
I assumed the dividing frequency for the D8.8 below 400 Hz. That's why I didn't even consider a solution with a dome midrange speaker.
A verified construction is a wish, realistically I see it as a certain experimentation. But the less of it, the better at the moment.

Yes, sound is primary. I must point out that considerations for using D6.8 are also made from the point of view of "aesthetics". The D6.8 loudspeakers belong to the same series as the D.8.8 and visually match each other. We also listen with our eyes, speakers live with us. I don't want to watch something I don't like. But as I wrote. A Tarkus clone may not be the only way.

In order to at least roughly check whether or not using the D8.8 in a clone is complete nonsense, I compared the HiVi D8.8 and the Peerless SLS-P830668 in WinISD (data from the data sheets were used).



Green - HiVi D8.8 - 30 l, 35 Hz, bassreflex diameter 70 mm / length 262 mm - recommended by the company
Yellow - HiVi D8.8 - 35 l, 35 Hz, bassreflex diameter 70 mm / length 176 mm
Red - HiVi D8.8 - 50L, 35Hz, bassreflex diameter 70mm / length 137mm (100mm / 310mm) - Tarkus clone volume estimate
Black - Peerless SLS-P830668 - 62 L, 30 Hz, bassreflex diameter 100 mm / length 342 mm - Tarkus
The HiVi D8.8 is in the QB3 Quasi-Butterworth approximation.
Peerless SLS-P830668 is in the C4/SC4 (Sub-)Chebyshew approximation (WinISD will primarily offer a closed baffle).

According to the technical sheets, both speakers have the same xmax - 8.3 mm and virtually identical Fs - HiVi - 32 Hz and 32.4 Hz Peerless. HiVi D8.8 is deceiving with its body. It has a diameter of 242 mm, which is practically a 10 inch speaker. But the Effective Piston Area is 0.0241 m2.

Further comparisons are possible from the technical data sheets in the attachment.
d8.8.pdf
SLS-P830668.pdf

I sent the speakers to be measured. And I'm curious about the differences between the published data and the measurement.

[foxes_lover]

I have this driver. It has quite different T/S values compare to manufacturer. You should make a measurement before modeling in WinISD.

[VitekM]

May I ask in what parameters and how does your speaker differ from the published data?

Yes, you are right, a more accurate simulation in WinISD will be only after a comprehensive measurement of the speakers. That's also why I sent them to be measured. And I am very curious how the actual data of my pair will differ from the published data and how the speakers will differ from each other.
My pair is from when Swans Diva 6.1 speakers were new to the market.

A basic simulation according to the data sheet is probably better than nothing to begin with. Or not?

[foxes_lover]

May I ask in what parameters and how does your speaker differ from the published data?

Yes, you are right, a more accurate simulation in WinISD will be only after a comprehensive measurement of the speakers. That's also why I sent them to be measured. And I am very curious how the actual data of my pair will differ from the published data and how the speakers will differ from each other.
My pair is from when Swans Diva 6.1 speakers were new to the market.

A basic simulation according to the data sheet is probably better than nothing to begin with. Or not?

Mine Qts is 0.71, Fs is 51Hz.

[duvixan]

Ok, so in this thread

https://techtalk.parts-express.com/forum/tech-talk-forum/44358-intimidation-meets-precision-the-apaches

you have the drivers used and a simulated crossover from an experienced forum member (Post #25)
Unless mattp shows up to share more info, that's it for now...

Good luck!

[VitekM]

Thank you for your help. You have helped me a lot. I appreciate it.

[wolf_teeth]

I helped as much as I could, but when images poof into the ether it's hard to see everything.

[VitekM]

I've gone through the entire link as well as the dedicated thread.
Thanks Wolf for the link to The Apaches and the blog with The Apaches V3.

[theSven]

I helped as much as I could, but when images poof into the ether it's hard to see everything.

I have the forum on HTGuide setup to pull a copy of the image and keep that locally now. That way if the link for the image dies the photo will live on here at the forum. It's frustrating when you want to see an old build or look at images and they are gone into the digital abyss.

[VitekM]

Next step.

Measured parameters of HiVi D8.8 and their comparison with available datasheets.

And here is the Impedance frequency response for speakers.


For those interested, I am attaching the Impedance frequency response in txt format.
HiVi_D88.1.txt
HiVi_D88.2.txt

This is what the result might look like.

The dimensions of the body are based on the original Tarkus, taking into account The Apaches.
From measured data and after simulation in WinISD - net volume 45l / 32 Hz / -3dB – 29 Hz
HiVi Q1R (but instead of the HiVi Q1R, I would prefer the SB Acoustic SB26STAC) and
HiVi D6.8b, which are available as a kit, are used as tweeter and midbass for now.
I would like to divide the crossover into two parts (location – red line in the corpus).