Bagby Kairos with 25W amp?

[Hikari]

I am seriously considering Bagby's Kairos kit. I like everything I've heard about the Satori drivers and this would be my first DIY speaker. My woodworking skills are limited to 8th grade woodshop but I have a good friend who has the tools and skills to do the cabs.

The thing is...I like Class A SS amps. Particularly my DIY Pass F5. It's 25W (actually more like 35W, the bias is jacked up) but plays nice with my current 90db efficient focal 2.5 ways.

I am worried that the Kairos at 86db efficient are really going to need more power. Anyone have expeience with the Kairos and lower-powered amps? The impedence is really flat on the Kairos which is good, they may not be as power hungry as there sensitivity implies. I don't listen real loud...about 90db at the listening position is as loud as I go.

Will 25W comfortably drive these speakers?

And finally a few questions about the cabinet design:

I understand the cab is undersized for a vented setup. But good for sealed. Would it be worthwhile to increase the depth of the cab from front to back (keeping the baffle dimensions the same) when vented? Size is not really an issue for me. bagby

[JRT]

Re: Bagby Kairos with 25W amp?

It is relatively simple math problem.

Need to know:
...loudspeaker's voltage sensitivity at 1 meter listening distance.
...the minimum (not nominal) impedance within the playback pass band.
...the listening distance.
...nominal playback level
...approximate crest factor in the source material you will listen to.
...desired headroom below onset of significant clipping.

What you will find is the crest power requirement.

Clipping usually shows as a sharp rise above an elbow on a THD+N curve, and "significant" clipping is arguably in the range of 5% - 10% THD. At half power below that, -3dB, a good amp usually exhibits much lower nonlinearity; but also, above that amplifiers usually show sharp rise in nonlinearity.

The ISO 226 equal loudness contours illustrate the nonlinearty of loudness perception mapped over most of what is audible and/or tolerable in frequency and level. The curve shows normal perception. Listening at proper level, the level intended by the mastering engineer, does not impose significant nonlinearity in normal perception. Listening at a level significantly different from what was intended by the mastering engineer imposes nonlinearity in that perception illustrated by the curve. This is different from the change in level imposed by change in listening distance, so a lower level is not perceived as being the same as sitting further back. Information about proper playback level is rarely provided by the publisher and mastering engineer, so optimal level remains subjective (should correlate with real live sound where appropriate).

http://en.wikipedia.org/wiki/Equal-loudness_contour

(need to go to work now, to be continued)

[JasonP]

Re: Bagby Kairos with 25W amp?

What is the listening distance?

[woodsart]

Re: Bagby Kairos with 25W amp?

Hi Hikari, I built the Karios and use the Marantz 2 channel PM8003 70WPC and a vintage Marantz 2238B @ 35WPC. These amps drive the Karios effortlessly!

An interesting thought, I prefer the vintage over the PM8003! (:

I can't imagine a 25W amp wouldn't do a good job.

I listen about 4-5' at my PC.....PLENTY of great sound!!

One thing I can guarantee is the performance of this amazing speakers!!!!

Robert

[Hikari]

Re: Bagby Kairos with 25W amp?

Thanks guys.

I listen about 9 feet from each speaker. Maybe 7 feet from the speaker plane. I have a big room about 25ft x 25feet with vaulted ceilings. It's on the floor of my house with an open floor plan. So it tends to suck up volume.

JRT:

I am familiar with the math. I am guessing I am using about 5 watts now, maybe 10-15 w/the Kairos. I bet 99% of people use less than 10 watts. But the market is flooded with 200+ watt amps. I can't tell you why...but I know that amps sound different regardless of how much wattage they are using. I think my 25W amp will drive the Kairos without clipping...but will it sound good?

woodsart:

I have seen your build thread. Thanks. It's been really informative. Have you tried the little Marantz in a non-nearfield set-up at loud volumes?

Thanks again guys!

[weskoki]

Re: Bagby Kairos with 25W amp?

I used to run F5+B1buffer on 86 db monitors.It sounded pretty anemic to me.

[woodsart]

Re: Bagby Kairos with 25W amp?

Thanks guys.

I listen about 9 feet from each speaker. Maybe 7 feet from the speaker plane. I have a big room about 25ft x 25feet with vaulted ceilings. It's on the floor of my house with an open floor plan. So it tends to suck up volume.

JRT:

I am familiar with the math. I am guessing I am using about 5 watts now, maybe 10-15 w/the Kairos. I bet 99% of people use less than 10 watts. But the market is flooded with 200+ watt amps. I can't tell you why...but I know that amps sound different regardless of how much wattage they are using. I think my 25W amp will drive the Kairos without clipping...but will it sound good?

woodsart:

I have seen your build thread. Thanks. It's been really informative. Have you tried the little Marantz in a non-nearfield set-up at loud volumes?

Thanks again guys!

Thanks Hikari, I am glad that I can help, however, I do not have the expertise others have in speaker building. I do have a good ear and I just can't find anything wrong with these. I just added a little DAC in place of the HRT MSII+. This is made by a Frenchman called Mini TDA1543 Starting Point Systems in France. Sounds very nice. The Kairos plays loud in my office area 9-10 o'clock on the 2238B and is a good listening level for me.

Which "little" Marantz are you referring to the PM8003 or the 2238B....ha ha LOL, neither are little!

I had the 2 set up in our family room 20X24, hardwoods and 9' ceilings, so what can I say except I could tell I needed louder volumes. The amp in there was the SR7005, I think 120WPC. I could try them again if you like. It was last year that I did this. I really don't remember much. I have the Triton MLTLs in there now with the theater. Jeff has no bad designs, only great sounding ones. The Kairos are no exception to this, I love these speakers. I have audition many speakers and heard some 25,000 dollar speakers. I know what my ears wanted and the Karios delivered that for me, particular wonderful, smooth bass at low volumes with either of my marantzes and DACs.

Another speaker (in the future) you might want to capture is the Continuum. I will build this one too. The only problem I see with this forum is that I want to build so many of these guys speakers, just can't do that. So many talented guys here, makes it really hard. As so as I decide on one another one pops up!

FYI, for future, I can guarantee you that if you picked up a Vintage Marantz you won't be sorry! The Kairos love Marantz!

Wish that I could give you some more advice on your amp.

Robert

[Hikari]

Re: Bagby Kairos with 25W amp?

I used to run F5+B1buffer on 86 db monitors.It sounded pretty anemic to me.

Yeah...I had no luck with passive preamps in front of the F5...even with 90 db towers. Just sounded thin and lacked dynamics.

Using Nelson's BA-3 front end as a preamp now...good combo.

Have you used your F5 with an active preamp into 85-ish db monitors?

[Hikari]

Re: Bagby Kairos with 25W amp?

Thanks Hikari, I am glad that I can help, however, I do not have the expertise others have in speaker building. I do have a good ear and I just can't find anything wrong with these. I just added a little DAC in place of the HRT MSII+. This is made by a Frenchman called Mini TDA1543 Starting Point Systems in France. Sounds very nice. The Kairos plays loud in my office area 9-10 o'clock on the 2238B and is a good listening level for me.

Which "little" Marantz are you referring to the PM8003 or the 2238B....ha ha LOL, neither are little!

I had the 2 set up in our family room 20X24, hardwoods and 9' ceilings, so what can I say except I could tell I needed louder volumes. The amp in there was the SR7005, I think 120WPC. I could try them again if you like. It was last year that I did this. I really don't remember much. I have the Triton MLTLs in there now with the theater. Jeff has no bad designs, only great sounding ones. The Kairos are no exception to this, I love these speakers. I have audition many speakers and heard some 25,000 dollar speakers. I know what my ears wanted and the Karios delivered that for me, particular wonderful, smooth bass at low volumes with either of my marantzes and DACs.

Another speaker (in the future) you might want to capture is the Continuum. I will build this one too. The only problem I see with this forum is that I want to build so many of these guys speakers, just can't do that. So many talented guys here, makes it really hard. As so as I decide on one another one pops up!

FYI, for future, I can guarantee you that if you picked up a Vintage Marantz you won't be sorry! The Kairos love Marantz!

Wish that I could give you some more advice on your amp.

Robert

Thanks for the offer. I don't think it's necessary but just a few more questions:

In your big room which you needed "louder volumes" in did you run the amp into clipping or did you just feel like it wasn't "filling" the room enough with the kairos? Also, how do you like the Kairos at low volumes? I listen a lot at night when the kids are asleep so low-volume articulation is important to me as well.

Thanks!

[weskoki]

Re: Bagby Kairos with 25W amp?

Never had a chance to listen to it with an active preamp unfortunately so i sold it and moved to AB class amps.

[woodsart]

Re: Bagby Kairos with 25W amp?

Thanks for the offer. I don't think it's necessary but just a few more questions:

In your big room which you needed "louder volumes" in did you run the amp into clipping or did you just feel like it wasn't "filling" the room enough with the kairos? Also, how do you like the Kairos at low volumes? I listen a lot at night when the kids are asleep so low-volume articulation is important to me as well.

Thanks!

Honestly, I just wanted to hear on a larger amp, it sounded great, just took a little more volume, that is all. But, I will try it again and get back with you.

Low listening, high volume listening, the Kairos delivers! Detail....smooth bass, full rich and solid. I used a 1.5" baffle too. Since this build was the most expensive build for me @ around 1K, I did not want any issues, so I sort of went overboard a bit.

I will try them again in the family room, take a pic and send it to you shortly!

Robert

[GranteedEV]

Re: Bagby Kairos with 25W amp?

I'm not sure I'd recommend the Kairos for a beginning woodworker due to its necessarily tilted-baffle.

[Hikari]

Re: Bagby Kairos with 25W amp?

I'm not sure I'd recommend the Kairos for a beginning woodworker due to its necessarily tilted-baffle.

I've got a friend who has all the tools and skills to do it. Actually, he's an engineer and has already made some CAD drawings of the Kairos with facets on the front...he's got a table saw, plunge router, jigs...all that stuff. We were going to do some single driver folded horns, he thought that would be easy. He thought the Kairos would be even easier.

[woodsart]

Re: Bagby Kairos with 25W amp?

I'm not sure I'd recommend the Kairos for a beginning woodworker due to its necessarily tilted-baffle.

Granteed, I agree, they are a bit tricky, but with patience and a cheap table saw and with a different blade, I was amazed how well these came together for a beginner such as I. Cutting those 14 Degree edges! 14 or 17 can't remember exactly! But as you can see in the pics, they are not too bad.

Hikari,

I took the Kairos into the family room (see pics) and you will see how lively this room is.

I plugged them into the Marantz SR7005, Pure Direct mode, IPhone 5, Spotify Premium with an app call Soundfocus....equalizer...with and without. The volume on the iPhone was from 75-90. These things played loud and clear....handled bass very well, I thought. There was enough volume for me, that is for sure.

Some songs with bass I played were....Ring of Fire and Your man by Home Free. High you are....a Branchez Remix, Raindance by African Tribal Orchestra....(love that group)!

The Kairos filled room with all the sound I needed. Honestly, I do not remember last year when I took them in there. Must be that my ears have changed or they have gotten better. I just don't know, seems they have improved over time....Maybe Jeff can chime in and let me know if he hears differently! (:

To me the way I describe them in my own terms is smooth, silky and full sounding! Very good at low levels.

Forgot, the ports were plugged in and I was 10' from the speakers!

If there was anything I would like to change with these is to see them as a tower!

Robert

[JasonP]

Re: Bagby Kairos with 25W amp?

For a distance of nine feet, simple calculations tell me that each Kairos at 25 watts will be producing ~90 db. You are on the edge here, and we'll ignore the needs of musical peaks and so on, but I wager you'll be ok.