Tweeters

I have tried hard to arrive at a short-list of tweeters I find interesting, so that I don't have to go browsing for days and weeks on Madisoud, Parts Express, Meniscus, and so on, every time I start planning a new project.

Tweeters are just tweeters. They have a job to do, and they need to do it right. If chosen with a certain amount of care, they impact the final sound less than midranges do. The impact on the final sound caused by driver-to-driver differences between two good tweeters is, in my humble opinion, less than that caused by driver-to-driver differences due to midranges or midbass drivers.

It's surprising how inexpensive some outstanding tweeters are, if your goals are similar to mine (accuracy, natural sound, low distortion).

Entry level tweeters

These are tweeters which I would not use in demanding applications or high budget projects. I'd use them when the demands placed on the tweeter are "easy", or when I have tight budgets.

• SB Acoustics SB19ST-C000-4: 19mm soft dome, Fs 980Hz, Sens 88.5 db, Madisound, USD 20. Very flat SPL curve till the end of range, good, smooth off-axis fall-off, no peaks or jaggedness. Going by just the graphs and data, it should handle low Fc points, but since it's a 3/4" dome, and has lowish 30W rated power, I will prefer to play safe and keep to 2.5KHz or higher, 2nd order or higher, to keep excursion within safe limits.
• Peerless (Vifa) XT25SC90-04: 19mm ring radiator, Fs 837, Sens 91.7 db, Madisound, USD 22. Good, flat SPL, can be used 2.5Khz or higher, small 65mm faceplate. I wouldn't use it with lower cutoffs; the distortion apparently increases rapidly below 2.5KHz. It's also not very good at handling very high power, but can be very practical for small MTM or TM speakers used at lower power, for smaller rooms. The slightly higher Fc constraint will pose no problem when used with benign midbass drivers like paper or poly cone.
• ScanSpeak Discovery D2606/9200: (formerly Vifa D27TG15), 25mm soft dome, Fs 1100 Hz, Sens 91.4 dB, Madisound, USD 34. Flat SPL right through, can be crossed over at 2.5KHz, steep slope.
• Peerless (Vifa) D27TG35-06: 25mm soft dome, Fs 912Hz, Sens 92.7 dB, Madisound, USD 28. Flat and smooth SPL, can be used above 2.5KHz. Will add "air" at the extreme top end because of a hump in SPL after 10KHz. Venerable and popular model, used in a lot of mainstream designs.
• ScanSpeak Discovery D2606/9220 (formerly Vifa D27TG35): 25mm soft dome, Fs 850Hz, Sens 91.4 dB, Madisound, USD 47. Flat SPL right through, can be crossed over at 2.5K steep slope. Older stock selling as Peerless D27TG35 at a much lower price.

High Fc applications

These tweeters may be very attractive on other counts, but can't be used with even a 2.5KHz crossover point. In general, most planar and ribbon tweeters fall into this category, unless the ribbons are very large. A few of the 19mm (3/4") domes also fall here.

• Seas 19TFF1 (H737): 19mm soft dome, Fs 1700, Sens 88 db, Madisound, USD 33. Flat SPL from about 2KHz to 30KHz. Can be used above 3KHz with a steep slope HP. The manufacturer data sheet recommends 4KHz or higher.
• Aurum Cantus G2Si: ribbon tweeter, 8.5mm x 60mm ribbon, Fs N/A, Sens 96 dB, Parts Express, USD 99. Can be crossed over safely above 3KHz, 3rd order, and with care below. The SPL rises by about 5dB from 5K to about 7.5K and stays high above this till beyond 20K. A great tweeter for high efficiency designs with easy midbass, midranges and FR drivers which are suitable to be crossed over at high Fc.

Very good mainstream tweeters

This set is what I'd use for general-purpose high quality speaker designs.

• Vifa NE19VTS-04: 19mm soft dome, Fs 743 Hz, Sens 88 dB, 80W, Madisound, USD 33. Flat SPL from 2.5KHz and up, small 52mm face plate, protector beam above the dome tweeter. High quality driver, from the Vifa NE range, all of which have neodymium magnets and distortion reducing features. The 25mm NE25VTS, USD 39, is a close cousin.
• Peerless XT25TG30-04: 25mm ring radiator, Fs 436, Sens 91 dB, 110 W, Madisound, USD 33, Parts Express, USD 28. Very flat SPL, can be crossed at 1.5KHz or higher. To keep harmonic distortion low, Fc should be higher than 2KHz.

  From Zaphaudio: "Smoothest and most extended response curve in the group, and resulting CSD is excellent. Good tall order HD above 2kHx, but average 2nd order HD. Poor HD levels of all types below 2kHz, even considering the extended low end. It may have a 500 Hz Fs, but don't think about crossing it below 2kHz LR4 or 2.5kHz LR2."

I would find it hard to find a better tweeter at this price point for any application if I can work with an Fc of 2KHz or higher. For lower Fc designs, I'll have to look elsewhere.

• ScanSpeak Discovery R2604/8320: 25mm ring radiator, Fs 500 Hz, Sens 90 dB, 100W, Madisound, USD 50. Very flat SPL curve, can be crossed low, 1.5KHz steep slope, high power handling. Better than the Vifa ring radiators in most areas.

My top-end tweeters

These are the outstanding ones. I'd use them for any design at any performance level.

There are two metal domes in this set. I'd use them unhesitatingly for top-end designs, and they dispel the myth that all metal domes sound harsh. (Some mediocre ones do.)

There's only one model in this set with a small face plate. This feature is very useful for MTM designs.

• SEAS Prestige 27TDFC (H1189): 25mm soft dome, Fs 550Hz, Sens 90 dB, Madisound, USD 47. Flat SPL right through other than a 2dB peak at about 14KHz. Very low distortion, probably the best performing tweeter in its price bracket. Can be crossed over 1250Hz steep slope.

  From Zaphaudio: "Exactly the same as the TBFCG, but with a fabric dome. Slightly rising top end response but overall very smooth. No ugly hexagrid. Similar to the old 27TFFC, but with a polymer surround and slightly cleaner performance."

• SEAS Prestige 27TBFC/G (H1212): 25mm aluminium/magnesium dome, Fs 550Hz, Sens 91.5 dB, 90W, Madisound, USD 50. Very low distortion, very flat SPL curve, cone breakup artefacts all outside audible range. Will handle 1250Hz Fc with a steep slope.

  From Zaphaudio: "Very smooth response, down a few dB at 20kHz. Very low distortion of all types, particularly the near non-existant high order harmonics. No notable energy storage problems. Ultrasonic breakup node at 26.5Khz. The hexagrid cover is ugly."

• SEAS Prestige 29TFF/W (H1318): 25mm soft dome, Fs 950 Hz, Sens 92 dB, 90W rating, Madisound, USD 52. Very flat SPL curve, can be crossed at 2K or higher, steep slope. Sexy two-tone front plate.

  From Zaphaudio: "Highish Fs, steep low end rolloff. Smooth response with 2dB droop on top end. Good CSD. Average 2nd order HD, increasing 3rd order at 1.2kHz. Best crossed over LR4 1.5kHz or above. Nice thick flange design. Very efficient."

• SB Acoustics SB29RDCN-C000-4: 25mm soft dome ring radiator, Fs 680 Hz, Sens 94 dB, 100W rating, Madisound, USD 57. Ruler flat SPL, high power rating, high sensitivity, low crossover possible. Small 63mm dia front plate. Also, very similar SB29RDC with a 4" face plate, USD 51, and SB26ADC aluminium dome, USD 51.

  See Troels Gravesen's page on testing SB tweeters. Superb low distortion measured by him for all of these.

  From Zaphaudio, about the SB29RDC: "Smooth response and low distortion - there's not a lot to complain about, even considering the price. It is a form of ring radiator, and it's no surprise that performance is quite a bit like a Vifa XT25, but the SB is cleaner on the low end. It does not have as much 3.5 kHz cliff in the response as it's cheaper brother. There are a few tweeters that perform a tiny bit better but cost a lot more."

• ScanSpeak Discovery D2608/9130 (formerly Peerless HDS 810921): 25mm soft dome, Fs 700 Hz, Sens 91.3 dB, 80W, Madisound, USD 75. Very low distortion, quite flat SPL with small peaks at 7-9KHz and 12-15KHz, can be crossed low. Best tweeter in its price category. For me, this is the tweeter I'll use for the highest level of performance. I used this tweeter for the Darbari.

  From Zaphaudio: "Also known as the new HDS tweeter. Peerless finally creates a world class tweeter to compete with the best from Seas and Scan-Speak. Very low distortion levels and smooth, controllable response. Minor FR dip at 6.5kHz. Beautiful cast metal frame. Reasonable price. There's not much to complain about here and this is one of the best in the group."

I actually believe that above this USD 75 price point (for the Peerless HDS tweeter), returns diminish sharply. Or, I don't know how to appreciate the incremental benefits of the USD 200 and USD 300 tweeters.

Midbass drivers: about 6-7"

These are the drivers which are used for 2-way designs which aim to cover the bottom end of music adequately. Anything bigger than this is often harder to use in a 2-way, and anything smaller often struggles to reach the in-room 40 Hz bottom end needed for music.

Entry level options

This is the kind of driver I'd use for budget projects.

• Dayton DA175-8: Fs 39Hz, Qts 0.58, Vas 16.3l, Xmax 4.2mm, Parts Express, USD 29. Good, low budget aluminium cone, stamped steel frame, dust cap, smooth SPL curve with relatively benign cone breakup, xo at 2.5K possible.
• Dayton DSA175-8: Fs 38.3Hz, Qts 0.29, Vas 19l, Parts Express, USD 37. From their so-called "Designer Series", which are the cheapest of all their "Series". Stamped steel frame, well-behaved aluminium cone, easy to cross over at moderate Fc.

Excellent mainstream options

These are a clear jump up in quality from the entry-level options. I look for at least a cast frame in this bracket.

• Fountek FW168: Fs 45Hz, Qts 0.397, Vas 16.5l, Xmax 4.6mm. Parts Express, USD 46. Good cast aluminium frame, anodised aluminium cone, phase plug, smooth SPL curve with cone breakups pushed high. Can be used for TM or MTM, xo even at 2.5KHz. T/S parameters may be incorrect.

Midbass drivers: about 5"

• SB Acoustics SB15NAC30: Fs 35.5Hz, Qts 0.37, Xmax 5mm, Vas 17.7l, Madisound, USD 48. Aluminium cone, cone breakups pushed beyond 5KHz, first peak at 7KHz, heavy cast frame.
• Scanspeak Discovery 15W/8434: Fs 45, Qts 0.25, Vas 12.8l, Xmax 4.2mm, Madisound, USD 65. Coated NRSC fibreglass cone, cast Al chassis, very smooth SPL till 5KHz, first peak at 6KHz.
• SB Acoustics SB15NRXC30: Fs 38, Qts 0.33, Vas 20.7l, Xmax 5mm, Madisound, USD 52. Paper cone, heavy cast Al chassis, flat SPL till 4KHz, first peak at 6KHz.
• Seas Prestige CA15RLY (H1216): Fs 44, Qts 0.34, Vas 14l, Xmax 5mm, Madisound, USD 83. Coated paper cone, thick cast frame, smooth SPL curve, mild and wide hump in the middle, 400Hz to 2KHz, no cone breakup peaks at all, usable frequency till 10KHz natural rolloff.
• SB Acoustics Satori MW13PNW: Fs 41.5, Qts 0.30, Vas 15l, Xmax 5mm, Madisound, USD 131. Heavy cast frame, white paper (they say "papyrus") cone, flat SPL up to 5KHz, first peak at 8KHz.