Changing Dynaudio 30W100 for Hivi D10.8 ??

[hommeout]

Hi Guys!!!

I need some advise about my current situation.
I've buy not so long ago a pair of used Duntech speaker.
I've just discover that my 4 woofer Dynaudio 30W100 are quited tired and need to be refoam.I wanna know if I could put 4 Hivi D10.8 to replace my old Dynaudio.
The problem is,my Dynaudio 30W100 are rated 6 Ohms and I drive the Duntech in a Bi-amp setup 4 Ohms for the Low,4 Ohms for the Mid and High.
I've just buy a D10.8 to see if it would fit in the Duntech and it does but the D10.8 are 8 Ohms.
Could I drive a 4 Hivi D10.8 setup in Bi-amp with 8 Ohms for the low without damaging the crossover of the Duntech.
A mean,I know absolutly nothing about passive Hi-Fi speaker.
Let me know!!
Thanks!

[David Gatti]

By replacing the Dynaudio with the Hivi you are seriously devaluing the Duntech. Its the Sovereign you're using I presume?

It is a classic speaker, designed for minimum phase, so the original woofer's parameters are critical if you want to achieve the original sound and accuracy.

It will probably sound OK, and wont do any physical harm using the HiVi, but you really should of gotten the Dynaudios refoamed.
The impedance curves on both drivers are infact fairly similar and the 30W100 spec sheet rates it as 8 ohms.

http://www.gattiweb.com/images/dynaudio/30w100_data.pdf

[hommeout]

Hi David

Thanks for the fast reply!!
My Duntech are Regent D-400.
I really appreciate your input on this.
The reason why I was looking for the Hi-Vi is because i've read quite alot of post on this forum and some people seem to think that the Hi-Vi are as good if not better the Dynaudio.
Like i've said before,I know nothing about the Hi-Fi world but I have a background in music studio and active studio monitor.
Thanks Again David!!!

[Inductor]

No, is not the same but they are very similar. The Dynaudio 30W100 is ruler flat from 50 to ~700Hz (or +/-1dB), Fs=24Hz, Re=5,85/Zmin=6,4Ohm, Le=0,73mH, Qts=0,619/Qms=2,70, Vas=269L, Sensitivity (1W/1m): 91dB.
Comparing with Hivi D10.8 (http://www.madisound.com/catalog/PDF/hivi_10-8.pdf) flat from 70 to ~400Hz (+/-1dB), Fs=24Hz, Re=6,5/Zmin~7,5Ohm, Le=?mH, Qts=0,41/Qms=6,84, Vas=147,3L, Sensitivity (2.83v/1m): 90dB.
A problem may arise at the xover frequency with a peak @500Hz with the HiVi interfering with the 175mm mids. Also as was said phase may also give a worse problem with the combined responses (Woofer/Mid). Also I don't know Xover frequency and order (?/?), I assume is about 200-300Hz/1-2order. Besides that (response) parameters are very similar (Qms is very highish or rigid).

You sure can get brand new rubber surrounds (and glue) from GoodHiFi: http://www.goodhifi.com/, in the mean-time you can listen to your new HiVi speakers and later build a new copycat system (diy a second pair) of the Duntech's.

[hommeout]

I've decide to have my old 30W100 refoam.I already have one D10.8 and I might buy another one to load one of the Duntech with the Hi-Vi and the other Duntech with 2 30W100 and let my ears be the final judge,you know,sometime spec are saying something but real test might say otherwise.
Thanks for your input!!!

[David Gatti]

Checkout speakerbits for genuine Dynaudio surrounds.

One day you will sell them and the buyer will be far more impressed if it has genuine Dynaudio parts.

[Inductor]

Now, the difference (with the box) you have with Dynaudio (~320L calc.box) an F3=30Hz and with the Hi-Vi a box smaller (also closed/check fig. for size) and F3=45Hz, so here there is a big difference on the low extends. You can only achieve same low frequencies with a BR box of ~100L tuned to 24,00Hz, simulated on WinISD software. As an example: You find an F3=30Hz with a BR box, with the Hi-Vi, of 90L/23,5Hz tuning freq. SPL is also about the same at 50Hz (111dB) with the BR box and ~109dB with the closed box of 60L. (or "almost half" the amount of sound you get at this frequency with the closed box and reduced interior volume)

[Inductor]

To be more accurate, next simulation should point for half size volume (the exact interior volume is not mentioned by the owner) or two speaker drivers and full size box.

[David Gatti]

From the specs page - REGENT, I'm estimating the enclosure volume per woofer is about 100 litres.

Inductor, can you redo the simulation for both drivers using that volume?

[infinia]

Originally Posted by David Gatti

Checkout speakerbits for genuine Dynaudio surrounds.

One day you will sell them and the buyer will be far more impressed if it has genuine Dynaudio parts.

yeah and he'll need to sell after paying those prices for those "bits" LOL
who'se to say that the replacement foam may be on their last legs even after finding a tech to install the said bits. A good tech should have something similar and the outside surround is not all that much to do with T/S anyway (mostly the spider is). Given if said surround is not too far off from available material and geometry ...see Troels site

My hat's off to you David for hosting Dynaudio stuff on the web for all these years. A real benifit to the audio community.
cheers