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Tectonic Elements TEBM65C20F-8 3-1/2" BMR Full-Range Speaker 8 Ohm

Brand:|Model: TEBM65C20F-8|Part # 297-2156
For audio applications that require extended frequency response, and superior off-axis response in a small form factor, choose the Tectonic Elements TEBM65C20F-8 3-1/2" full-range transducer. Nearly all of the audio in the pass band of the driver is available up to 100° off-axis.
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Part # 297-2156
  • Amazing off-axis frequency response
  • Small form factor with decent Xmax
  • Perfect for modern speaker applications such as soundbars

Product Details

Tectonic Elements TEBM65C20F-8 3-1/2" BMR Full-Range Speaker 8 Ohm
Tectonic Elements TEBM65C20F-8 Balanced-Mode Radiator (BMR) features extended frequency response and wide dispersion compared to that of a conventional drive unit. It combines the benefits of Tectonic Elements bending-wave technology and pistonic modes of operation. It is ideally suited for compact audio applications that require a full-range, high performance acoustic solution such as a soundbar. An advanced ferrite-based motor is combined with special cone dampers to ensure a small size that outperforms conventional drivers, especially in off-axis performance.

Product Specifications
  • Nominal Diameter3-1/2"
  • Power Handling (RMS)20 Watts
  • Power Handling (max)40 Watts
  • Impedance8 ohms
  • Frequency Response80 to 20,000 Hz
  • Sensitivity81 dB 2.83V/1m
  • Voice Coil Diameter1"
Thiele-Small Parameters
  • Resonant Frequency (Fs)86 Hz
  • DC Resistance (Re)7.2 ohms
  • Voice Coil Inductance (Le)0.055 mH
  • Mechanical Q (Qms)4.9
  • Electromagnetic Q (Qes)1.09
  • Total Q (Qts)0.89
  • Compliance Equivalent Volume (Vas)0.04 ft.³
  • Mechanical Compliance of Suspension (Cms)0.65 mm/N
  • BL Product (BL)4.33 Tm
  • Diaphragm Mass Inc. Airload (Mms)5.25g
  • Maximum Linear Excursion (Xmax)3.5 mm
Materials of Construction
  • Cone MaterialPaper
  • Magnet MaterialFerrite
Mounting Information
  • Overall Outside Diameter4.25"
  • Baffle Cutout Diameter3.4"
  • Depth1.88"
  • # Mounting Holes6
Optimum Cabinet Size (determined using BassBox 6 Pro High Fidelity suggestion)
  • Sealed Volume0.1 ft.³
  • Sealed F384 Hz
  • Vented Volume0.2 ft.³
  • Vented F350 Hz
Tectonic Elements TEBM65C20F-8 3-1/2" BMR Full-Range Speaker 8 Ohm
  • BrandTectonic Elements
  • ModelTEBM65C20F-8
  • Part Number297-2156
  • UPC844632098789
  • Product CategoryMidrange / Midbass Drivers & Full-Range Speakers
  • Unit of MeasureEA
  • Product Rating
    (25 Reviews)
  • Weight1.6500 lbs.
  • California Prop 65

    Warning: California residents only. Please note per Proposition 65 that this product may contain chemicals known to the State of California to cause cancer and birth defects or other reproductive harm.

View similar products to the Tectonic Elements TEBM65C20F-8 3-1/2" BMR Full-Range Speaker 8 Ohm
in the Midrange / Midbass Drivers & Full-Range Speakers product category.


Tectonic Elements TEBM65C20F-8 3-1/2" BMR Full-Range Speaker 8 Ohm
Tectonic Elements TEBM65C20F-8 3-1/2" BMR Full-Range Speaker 8 Ohm is rated 4.52 out of 5 by 25.
Rated 4 out of 5 by from Found their purposeI bought these some time ago as midbass speakers in a 3 way setup and they worked pretty good but the enclosure was junk so they sat for a while I recently purchased the peerless 3 1/2" passive radiator and saw a review where Matt P said these Tectonic drivers in a .21 cubic ft box would pair up nicely with it. Well, he was right. I built a small powered box with an EBB PREAMP and a 34watt X2 amp with a pair of 1" tweeters ( you need tweeters). They're crossed around 3500hz, sound really good and have great bass extension with the passive.
Date published: 2016-02-04
Rated 4 out of 5 by from Fantastic valueI purchased 4 of these speakers for my project and was blown away by the quality of these speakers. You can not get close to any other speaker in this size for the price!The only thing I would add is that they are not what I would call truly "full range." They are very impressive in the lower frequencies, especially for their size, but they really need an additional tweeter to augment the overall frequency response. That being said, I highly recommend these speakers and would recommend them to my friends, indeed..
Date published: 2016-01-11
Rated 1 out of 5 by from Allmost usable for very low-fi apps.Picked some up for a desktop project, measured response looks like the spec sheet, massive phase wrap in the 1.2kHz range, unusable for my application, no amount of DSP will fix this one...
Date published: 2014-12-23
Rated 4 out of 5 by from Great full rangeThis is a great full-range and you will get your moneys worth with the correct cabinet.The reason I only gave it 4 stars is because I prefer the Vifa TC9FD-18-08 because it is a bit more clear in the mids and highs, however, the Techtonic does put out more bass.I will have a 3''-ish budget fullrange shoot-out using: Vifa TC9FD-18-08, Tectonic Elements TEBM65C20F, HiVi B3N, Dayton Audio ND91-8, Fountek FE85, and the Hi-Vi C3N-III (not sold on PE). If you would like me to add any other drivers let me know and i will make my best attempt to add it to the shoot-out.
Date published: 2014-11-02
Rated 5 out of 5 by from Awesome Full Range!Although the bmr's I bought were hi-wave these have almost if not exact specs. So I used six of them and two cheap tweeters to make a portable boombox. The box is 22x20x20 with two 2"ports 6" long. It is powered by a kenwood bt310 and a 400watt kenwood amp. My power source is a computer power supply wired @12volts. At first listen it was a bit boomy in the bass but I placed it on a cooler at work and over time it has just opened up with great highs and lows and just enough midrange to satisfy just about anyone in my opinion. Thes bmrs are a steal no matter how you look at it. Very heavy for a small driver. They crank too!
Date published: 2014-10-29
Rated 5 out of 5 by from unexpected resultsI bought a pair of these this month for a little project to use at work. They were listed as full range speakers. I expected highs and mids, but i did not expected the amount of bass that came from such a small speakers. I got more than what i paid for.
Date published: 2014-10-26
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Product Q&A

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Tectonic Elements TEBM65C20F-8 3-1/2" BMR Full-Range Speaker 8 Ohm

You recommended a .4ft^3 enclosure and 2" wide 4" long port for 2 of these speakers. Will 2 1" wide 2" long ports work? Also, with the volume, does it matter about the L x W x H as long as its .4^ft^3?

Asked by: RonnieT
Those port dimensions will work out to a similar tuning frequency but there may be more port noise problems at higher volumes. The shape of the box will not matter as long as the volume is 0.4 cubic feet.
Answered by: MattP
Date published: 2015-12-22

Hi, my design dictates a maximum enclosure volume is 0.14 cubic feet.  Will I get better low end performance with a ported or sealed enclosure at this volume?  If ported, what size should the port be? Thanks!

Asked by: shawnrk
Better low end will come from a ported enclosure. I would recommend a 1" diameter, 3" long port for this volume, which will tune to around 60 Hz.
Answered by: MattP
Date published: 2015-09-21

I wonder about matching between this unit and passive radiator. And can you recommand enclosure volume for passive radiator?

Asked by: ssunoland
Using the Peerless passive radiator, a volume of .2 cubic feet is recommended. With no weight added you will have a tuning frequency of about 60 Hz and an F3 of 73 Hz.
Answered by: MattP
Date published: 2016-01-26

I'm wanting to use these speakers as surrounds in a diy 5.1 build and I was wondering what dimensions to use for a sealed, single speaker enclosure, that not only sounds good, but is as compact as possible. Thanks

Asked by: Advant1224
The smallest I would go for is 0.1 cubic feet which would work out to a 5-1/2" cube, internally. Using 1/2" thick material it would be a 6-1/2" cube.
Answered by: MattP
Date published: 2015-06-04

I would like to pair one of these with a Peerless PMT40N25AL01-04 1.5" full range speaker with a crossover at around 1khz. Can you recommend a crossover capacitor value and sealed enclosure size for this setup?

Asked by: stan165
Please contact our tech support for more help with this question, or 800-338-0531 x1.
Answered by: MattP
Date published: 2015-05-19

Good Evening Question 1 Can I use two tectonic elements HIBM65C20F-8 3-1 / 2 "BMR full-range speakers 8 ohm with an Peerless 830.878 3-1 / 2 "Passive Radiator or which one Speaker work good with the Radiator?

Asked by: Elchbrei
Please contact our tech support for more help with this question, or 800-338-0531 x1.
Answered by: MattP
Date published: 2015-03-16
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