[DSK]

yeah 1x rear port.

pat said he was going to use a PHL now that he cant get cabasse.

at least im pretty sure that is what he said.  Ill find out for you.

Thanks WerTicus, I'd be interested to know whether his replacement driver is suitable for a sealed box too  

Rocket mentioned that he preferred the Stealth (MTM with Raven R1 & 2 x Accuton ceramic 7" drivers) over the Ref1. Have you heard the Stealth?

[Rocket]

Hi Dsk,

A friend has the only pair that were made, they were a custom one off design for him.

I guess what i'm trying to articulate is if you are going to be spending a lot of money you really need audition them for yourself.  You should pop over for a visit.

The reference 1's are excellent sounding speakers and are a couple of levels better than mine.  I am a really big fan of the phl drivers but then again other people may think differently.  I think they sound as good as the accuton drivers.

Regards

Rocket

[jules]

Werticus,

this cross over design thing ... I'm wondering if I should have a go. Does it require any specific equipment? Is it trial and error (requiring experienced guesswork) or can it be pinned down to specific calaulations?

Any recommendations for books on the subject?

jules

[jules]

DSK,

You seem to be pleased with some aspects of your ambience system but at the same time you are also looking for a change. I notice that the ribbon covers everything down to 440Hz which really leaves the Seas with only 100 to 440Hz to cover [if we are talking -3db at the low end]. It looks as though they would have been better off to either use a bigger woofer, maybe 10" or even 12" if the ribbon really is good down to that frequency.

On the other hand maybe it was a bit optimistic to ask the ribbon to go so low and some change in the crossover point could make a big difference to the character of the system although box design might make that hard.

What do you think?

jules

ps sent you a pm on servo-sub details

[DSK]

DSK,

You seem to be pleased with some aspects of your ambience system but at the same time you are also looking for a change. I notice that the ribbon covers everything down to 440Hz which really leaves the Seas with only 100 to 440Hz to cover [if we are talking -3db at the low end]. It looks as though they would have been better off to either use a bigger woofer, maybe 10" or even 12" if the ribbon really is good down to that frequency.

On the other hand maybe it was a bit optimistic to ask the ribbribbon to go so low and some change in the crossover point could make a big difference to the character of the system although box design might make that hard.

What do you think?  ...

Hi Jules,
No, I disagree completely     Integration of a larger woofer with a ribbon is far harder and is unlikely to be as satisfying or seamless. It is far better to get the integration right, then supplement the very bottom end with a subwoofer if necessary (may not be required in a smaller room).

Though they move less air, smaller woofers are typically "faster" with better transient response and articulation. This is critical in matching to a driver with the speed and detail of a ribbon. The custom SEAS driver in the Ambience has useful bass to below 30hz so the extension is not so much the issue as the lack of weight/body/warmth from a woofer this size in a room my size. Carefully set up without the sub, the Ambiences provided excellent bass (even in my room) and it was personal taste that led me to add a subwoofer for that lifelike bass that you feel as well as hear. Some people may not have felt the need. With the sub, you feel the impact more and have greater dynamics, so there is less need to turn the volume up further and therefore less stress on the SEAS woofer too.

Bear in mind, that my room still needs a little more absorption. The mids/highs tend to be a little emphasized versus the bass, which can make the sound slightly cold or thin. The sub helps me balance things out tonally and add back a little warmth. Once the room is totally treated, I may need to back off the sub a little ...we'll see.

In the last week or so, I rebuilt some absorption panels to make them more effective. Though the room still needs more absorption to reduce the RT60 to optimal levels, the improvements were surprising in both scale and scope. The sound I'm getting now is truly amazing and it is evident that it was still the room, not the speakers or equipment, holding me back. Every decent recording now pulls me into the performance and I thoroughly enjoy every listening session. This was not the case before.
The performance of the Ambience ribbons equals anything I have heard and the bass, combined with the Rythmik sub (low-Q, sealed, servo, rigid) is now exceptional to below 20hz as well. To achieve such performance,  bandwidth and coherence from a dynamic speaker would be very difficult and very expensive. I will re-evaluate once I've completed room acoustic treatment, but it seems unlikely now that I will pursue a speaker change. I am very happy indeed with the lifelikeness of my system now.  

[jules]

Wot ...   , you completely disagree!

In your situation, backed by a sub, I think the ambience set up looks fine. My question about the size of the [Seas] woofer was really on the basis of using the Ambience without a sub. I know that a speaker of that size does "respond" in some way to low frequency but to me it's not a tone so much  as the sound of a stick hitting wet cardboard. I'm not sure what it's made up of, maybe it's harmonic overtones or maybe it's just struggling but since the lowest note on a piano is about 27 Hz [and there's many other examples down there] it is important.

What surprises me in general is that so many speaker systems have a 6-7" bass underpinning them. Frequency response graphs for all of them are pretty similar and really don't do much below 70 Hz. In the case of the Ambience system, given that you reckon the ribbon is great down to 440 Hz I still can't see why they didn't use a slightly larger Seas, in that a 10" would still have been quite comfortable with the 440 at the top of its range and yet the bass would have been improved in terms of weight and body if you like but also just in terms of accuracy of reproducing the full original note.  

In terms of integrating your sub with the ambience what approach have you taken to the crossover issue?  I guess it's one thing to tune the highpass of a sub xover but it's not quite so easy to do anything to the low end of an existing system. In that sense, it probably works to have something like a 6 or 7" woofer that rolls off sharply at about 70 Hz and doesn't compete with the sub. I have had a response from Brian [Direct servo] suggesting the use of "first order RC attenuation on the input of the Aksa 55" as the best solution to this problem [at least I think that's what he was saying   . Technically, evaluating this idea is above my head but I would be interested in others opinions here.

jules

[DSK]

Hi Jules.

My question about the size of the [Seas] woofer was really on the basis of using the Ambience without a sub.

Yep, I understood that. What I was suggesting was that (typically) the smaller the woofer, the better it performs in the upper bass and lower mids. Regardless of the crossover point, the woofer will play up into the mids. Therefore, I would rather sacrifice bottom end weight than upper bass/lower midrange articulation/speed.

I know that a speaker of that size does "respond" in some way to low frequency but to me it's not a tone so much as the sound of a stick hitting wet cardboard. I'm not sure what it's made up of, maybe it's harmonic overtones or maybe it's just struggling but since the lowest note on a piano is about 27 Hz [and there's many other examples down there] it is important.

I agree that smaller woofers lack sufficient output to add sufficient weight to the fundamentals of instruments reaching down to the lower frequencies. This causes an imbalance where the overtones have more emphasis than the fundamentals and this causes a thin or cold presentation lacking body, warmth, weight, dynamics. This was what I have been enduring for some time ...until I added the sub.

In terms of integrating your sub with the ambience what approach have you taken to the crossover issue? I guess it's one thing to tune the highpass of a sub xover but it's not quite so easy to do anything to the low end of an existing system.

The AKSA amp and Rythmik servo plate amp both run off the GK-1 pre-amp. I have 2 sets of outputs, one off the solid state section (for sub) and one of the tube section (for AKSA). I plugged the Ambiences ports to produce a quasi sealed setup and integrated the sub via ETF measurement software and ear. I contemplated such things as adding 1st or 2nd order HP filters to the Ambiences (either in the AKSA or via passive inline filters) but the sub is so well integrated and everything sounds so good that I have dropped this idea for now. The addition of the sub has meant that I no longer have to turn the volume up as far to get the impact and involvement and weight and dynamics of the performance. As a result, the Ambience woofer is not working as hard and would be causing less distortion, overhang etc. So, I don't think the HP filter would really add any audible benefit unless I played music at ear bleed levels ...which I don't.