best 4.5" midrange drivers under $1K

I am not sure - those are pretty extreme specifications - do you understand what you are asking for?

This is the only thing I can think of that nearly meets your specs is ACCUTON C²79-6.

I would not design around a tweeter.

I'd start with midrange first and then find tweeter and woofer to match.

If you use accuton that low then I'd use two per speaker.

I assumed you wanted metal/ceramic instead of damped designs like paper/poly/fabric.

Another option Jordan JX92S - this will be comfortable in the range you require but it will roll off a bit in dispersion above 2 KHz.

Funny, but I prefer paper for its snappy sound. Poly cones sound smoother but sort of dead IMHO.

Exactly my thinking. Poly makes a good material for two way woofer/midbass - not my first choice in a midrange though. It is funny how perceptions are different.

@shadorne: Im trying to find to best my excel midrange, i know theyr colder than paper but to me they deliver clear and as-is presentation

Shadorne, I would guess you are a fan of the dome midrange? What material?

If Audioism is looking for highly regarded midrange drivers then the ATC SM75-150S should be on his list.

There is a guy called SHINOBIWAN who has done extensive DIY using the driver - I'd google/contact him for help if you are intrigued. Some people really like to criticize it - but it has been around for more than two decades - so it is pretty popular despite being expensive.

The problem is that this driver is so powerful that I am not sure if any ribbon could keep up. It also needs sharp crossover filtering and distortion rises rapidly at low levels. Basically Audioism would need to start a design from scratch - so I did not suggest it.

It is apparently the only dual spider midrange dome in existance apart from a version by PMC which is apparently similar to its junior brother the SM75-150 - non "s" verison. The engineering/tolerances are painful and most other midrange domes (like the Vifa) will distort all too quickly at even modest volume levels - so midrange domes are not such a good choice in general especially cheap ones. This picture shows the "S" on the left and its junior brother on the right. Needless to say this is an absolutely massive drive motor for a 3" doped fabric dome (3" Voice coil) - in fact it far bigger than the vast majority of woofers. It is generally regarded as sounding faster than anything else except perhaps electrostatics (but will naturally go way louder than panels). It is also regarded as an expensive and difficult driver to match and best executed in an active design. Not something to start a DIY with, IMHO.

I totally agree with Gregm. I would be tempted to double up on most 4.5" midranges when working to 150 Hz. I am skeptical that even the accutons could work well that low even if doubled up at all but the most modest of volumes.

Pulp Paper is underated. It is very fast. It is also resonably damped inmternally (the big issue you get when you go metal/ceramic is "ringing" and the need to consider notch filtering to reduce its audibility).

but have you tried excels?

No. But I am old school and a woofer or mid/bass with a voice coil diameter barely bigger than a typical tweeter kind of rules them out for me. You are talking thermal compression big time, IMHO - even at modest levels.

yeah it's 4in afterall..i cant go bigger cause dont wanna to rework much on enclosure and my listening space is limited if not small

The cone may be 4" but have you looked at the specifications for the voice coil. It probably uses a 26 MM diameter overhung voice coil - a diameter no bigger than most dome tweeters. These tend to get hot as the small surface area and long coil in a short gap and which means that heat dissipation can be a challenge. The metal phase plug is intended to help cool the pole piece but it is the voice coil that will get the hottest.

Cdc,

It all depends at what level the test is conducted and even the units are different. Shinobiwan's test was equivalent to 96 db spl at 1 meter without an infinite baffle (so the low end distortion rises as you go below 600 Hz as the driver loses the baffle assistance or half space 6db boost to the lower frequencies).

Tangband test appears to be done at what looks like 96dB at 1/2 meter or equivalent to 90 db spl at 1 Meter with an infinte baffle.

If you only need modest SPL's then the Tangband is great option but I doubt it can go much above the level at which it was tested. (Of course you could use two in Appolito config to gain some SPL!)

SPL level requirement is the key parameter that governs whether a cheap driver will be good enough or not.

Audioism,

In simple terms the ATC unit was tested at 6 db higher SPL and yet the THD is about 10 db SPL lower - and it can probably play even much louder cleanly. Furthermore, if you look more carefully you will see that 3rd order harmonic distortion is about 20 db SPL lower on the ATC unit. At the end of the day there is no free lunch - the Tangband is excellent but you can only expect so much at $55 (my guess is your Seas Excel is probably a much better driver).

Cdc,

SPL level is 20 * Log (Absolute THD) - therefore ATC would appear at 60 db SPL down if it were on the same kind of SPL plot. For 0.1% THD you get = 20 * Log (0.001) = 60 db SPL. This may cause all the confusion in the comparison. There is very little out there that is so low - especially the 3rd harmonic which is much more detrimental then the 2nd and appears to be down around 70 db SPL ( this low level may be capable to show up problems of electronic distortion).

You may be right about the level - in any case that driver has no problem at 100 db SPL as it can go to 121 db SPL with 10 db of headroom at 0.3% THD, as in the implementation in the 300's