As this thread has prompted a lot of debate, I thought I�d add to Kingsrule and Crion�s findings and post some detailed thoughts on my own experience. Sorry, it�s long post �

I�ve had my GISO GB for three days now and installed it immediately before the ID41 card on my 808v5. First, it�s definitely not a one-note or even a half-hour demo. It took me a lot of time to get my head around what was different in the music and to decide whether all the changes were desirable ones. The impact of the GISO has also changed for the better since I first installed it, so it looks like it needs to burn in.

If someone had forced me to choose whether or not to keep the GSIO in the first half hour of listening, I�d have given a firm �no� and gone down the pub. To save you reading the painfully long post below, as of this evening, if someone took the GISO out of my system, I�d chase after them with a big bat.

I spent a fair bit of time listening to music with and without the GISO today (afternoon off). I�ve never had to think so hard about the impact of one piece of kit in my system, and nor have I ever gone from being ambivalent and slightly negative to liking the impact so comprehensively. The bottom line is that this is a slow-burn effect and one that needs serious listening in a given system before deciding either way.

For anyone who is interested and not easily bored, my detailed thoughts below:

1. Detail:
There�s significantly more detail, especially on good recordings, where you hear much more reverb and sense of the acoustic. But on initial listening, it�s tempting to think the opposite. Superficially, the sound without GISO feels more detailed, but when you switch the unit in and out, it becomes clear that the GISO sound is smoother and more organic (fits Crion and Kingsrule�s findings). Listening closely, you soon notice that there is actually significantly more detail with the GISO, but it�s very sweet and un-forced detail. By comparison, the non-GISO sound is a little �spitty and gritty� at the top end.

2. Soundstage & focus:
The soundstage is significantly wider with the GISO, but this took a good day or so to come out clearly and initially felt narrower and slightly blurred. The soundstage is also noticeably more coherent and this has more impact on the music than sheer width. Switching the GISO in and out, it�s as if the GISO removes a lot of clutter: everything becomes better defined in the soundstage, but not artificially so. You can hear right into the soundstage and there is a stronger sense of front-to-back space within it.

3. Rhythm and dynamics:
This aspect puzzled me for a while and practically turned my brain inside out. I initially felt that the GISO slowed the sound down quite significantly, taking some of the punch out and upsetting the overall feeling of rhythm. After listening for longer, this feeling went away. In fact, doing A-B comparisons, the GISO sound is certainly more energetic and snappy across the whole range. This could be down to burn-in or my ears getting used to the new sound (or both), but there is certainly a real improvement in dynamics across the range now. Crion, this fits what you heard as well.

4. Bass:
Strange to write about bass in particular, but the changes in bass also really confused me for a while. In fact, it turned out to be closely connected with my experience on rhythm and dynamics. I played a lot of music with deep, punchy bass and initially felt that the speed of bass notes was reduced � i.e. softer edges. But, again, switching back and forth, it became clear that something very different was happening. First, the GISO sound goes deeper than the non-GISO sound and bass notes are more tuneful. I think it�s the extra depth that confused me, in that I initially thought there was a slight softening. But when I stopped listening to bass in isolation and went back to listening to the music overall, there was clearly more punch, snap and energy to the sound � it felt right.

5. More relaxing sound:
This feels like a contradiction, but while there is more energy, detail and punch in the sound, it�s more relaxed, coherent and un-fatiguing to listen to. One thing I noticed consistently is that I end up listening at higher levels with the GISO in. So, where I�d previously listen at level 60 on the 7200s, I now find myself cranking it up to 65 or higher. It�s just so much more relaxed and natural � as if a lot of the grit and grain that you never noticed before has been taken away. This is really noticeable on voices, which sound fuller, richer and more textured (in line with Kingsrule�s thoughts). I wonder if this more relaxed, open sound is what initially fooled me into thinking the sound had slowed down.

So in summary, the impact of the GISO takes a bit of getting used to. For me and my system, after two days, I�ve gone from �not sure� to loving the overall impact. If I listen for a couple of hours and then take the GISO out, I immediately feel bereaved. There�ll be others like me on this forum, with a background in electrical engineering, who know there are scientifically sound arguments as to why such a device might make a positive difference. So my mind was open, but I�ve been very surprised by the extent of the improvement and that, as yet, there appears to be no downside.

So these are my impressions based on my experience. I hope they�re helpful to others who are interested in the GISO or other isolation devices.

PS. Thanks Cujo for sticking your neck out and raising this topic � you�ve done a big favour for me in giving me great value upgrade that I would otherwise never have contemplated. Likewise, Kingsrule and Crion for sharing your hands-on experience.

Caveat
My system is running on a dedicated mains supply, which reduces noise significantly, while improving detail and dynamics. I have a friend on this forum a few miles away who has similar kit to mine, but without dedicated mains. So I�ll lend the GISO to him to get a feel for how it performs in that situation.

Dave

808v5, MD600 & DSP7200.1
Dedicated audio mains supply