ND91-4 3-1/2" Aluminum Cone Full-Range Neo Driver 4 Ohm

Bought this as a small subwoofer to pair with some small bookshelf speakers I built with 3" full range tang band drivers. I have built and owned many speakers and this driver still surprised me. I was hoping for a bit more low end, comparable to your average bookshelf speakers, and paired with a 5-1/4" passive radiator and a 25 watt amp, this thing is a legitimate subwoofer. I haven't measured it, but I would put the frequency response of my setup, in an enclosure that's only about .25 cubic ft, to be around 40hz. Very impressive for such a small driver.

Beautiful! Used for my custom Bluetooth speaker. Mount front or rear, comes with extra gasket.

They make surprising amounts of bass for such a small speaker.

While I know this may sound like a stretch, hear me out; I saw a YouTube video about 12 or so years ago where someone used a version of these in a giant subwoofer box tuned to 30-hz, to which they rattled the car go pieces it seemed, immediately sparking my interest in a build with these. Fast forward to now, I had some time and money and decided to get them due to a cheap set of powered desktop studio monitors on sale on Amazon I could use to house these. With 30W RMS on the amp, it's a little underpowered to power these so the volume knob had to be turned up on the speakers to account for the 10W higher RMS. Other than that, and the speaker mounting face being smaller than the Behringer 3.5", these are an amazing value, blowing the stock speakers out of the park, even when not broken in. I will decide how to enhance the sound profile of the speakers even more with acoustic packing on the inside once I determine the best route without losing too much interior volume. If my truck takes this size of speakers, I am for sure going to install as many as I can :-) **Update: Context: My computer volume level was only at 22/100 before turning them down to speak, these things will ring!

Very good sound quality very light but make sure you don't ever drop your cabinet. The whole motor magnetic came delaminated from the basket completely useless now

Everywhere on the internet, people are using these for small enclosure computer speakers or bluetooth speakers. So i have a different take since I used this in car audio. My car has a 3.5" on the dash. I was originally going to use a coaxial but decided against it. However, All the well known midrange speakers from car audio brands are up there in price. This woofer was reasonable in price so I gave it a shot. Pros : super clear. More full sounding than most 3 inch speakers. free air, I was able to cross at 140 Hz high pass with a good result. Low pass was set at 6500 hz @12db/oct Cons: it's not true full range, it needs to be crossed as part of a 3 way system

Have bought these before much better replacements to originals

I thought when i ordered this product it would be a pair of speakers. That is how you normally buy speakers. But this was only a single driver. For the price, i could have bought others with equal quality that came as a pair. Sound quality is good. I have them hooked up to a mini amp and they sound well. No real bass, but that is not why you would buy this speaker.

Ce modèle de haut parleur ND91-4 est vraiment très performant pour sa taille et son prix et mérite 5 étoiles. C'est le second que je commande et ça manque cruellement de renforts en polystyrène niveau packaging... C'est triste, ce beau petit HP mort écrabouillé pendant le transport, voir photos. Au moins on a une belle vue éclatée de la voice coil et du système magnétique avec sa bague de démodulation en cuivre. Je repasse en 5 étoiles quand le vendeur m'aura envoyé le produit.

Ce HP large bande a une bonne réputation aux USA, mais il manque cruellement d'aigües - au-delà de 6-8000Hz la baisse est trop rapide, alors que pourtant il est capable d'une belle netteté si on équalise un peu en préamplification. Ou alors il faut lui adjoindre un circuit de compensation, ce qui enlève tout intérêt à ce type de HP qui est fait pour du câblage direct, sans filtre. Pou les basses, c'est surprenant de voir ce qu'une si petite membrane peut produire. Pour peu, encore une fois, qu'on l'amplifie ou filtre correctement et qu'on le place dans un volume suffisant pour ne pas l'étouffer. Adjoindre un bass-reflex ou ligne de transmission peut améliorer les choses mais attention à ne pas vous planter dans les calculs de volume et de longueur de ligne. Un si petit HP ne rentre plus dans les normes des softs de calcul... Bref, beaucoup de potentiel mais difficile à maîtriser. Attention à la faible puissance, amplifier avec prudence...