Monoprice MP-T65RT Measurements and Analysis
The Monoprice MP-T65RTs were measured in free-air at a height of 9 feet at a 1-meter distance from the microphone, and the measurements were gated at an 11-millisecond delay. In this time window, some resolution is lost below 200 Hz and accuracy is completely lost below 100 Hz. Measurements have been smoothed at a 1/24 octave resolution.
The above graph shows the direct-axis frequency response and other curves that describe the speaker’s amplitude response in a number of ways. For more information about the meaning of these curves, please refer to our article Objective Loudspeaker Measurements to Predict Subjective Preferences. The most immediate feature that leaps out here is that the on-axis response is not the flattest that we have ever seen. This is not surprising for loudspeakers in this price range. There is some peakishness in the 3 kHz to 4 kHz that is likely the result of cone breakup since there is no low-pass filter implemented to tame the woofer’s higher-end response. This peak is relatively contained though and only occupies a quarter of an octave, so while it may be audible, it shouldn’t be that intrusive. It may add a slight sibilance to certain parts of speech. The MP-T65RT’s response does ramp up a bit above 10 kHz, but this is even less of an issue since there is not much recorded content in that range. That extra energy centers around 15 kHz and wouldn’t do much more than give these speakers a bit more ‘air’ in recordings that actually have some content in that range. The ‘Listening Window’ tells largely the same story as the on-axis curve, that this response basically continues out to a 30-degree angle in the horizontal axis.
For those familiar with this family of curves, there are a couple of interesting details that emerge which we will explore in greater detail below. One is the relatively stable ‘early reflections’ curve. This curve is pretty well contained within a 4 dB window. The other detail is the low levels of the directivity indexes; that indicates that these are going to be rather wide dispersion speakers in some manner. The combination of the relative stability of the ‘early reflections’ curve along with the low level of the directivity indexes hint at a very cool feature of the MP-T65RT, so let’s take a closer look at what is going on here…
The above graphs depict the MP-T65RT’s lateral responses out to 95-degrees in five-degree increments. Here we get a more detailed look at the horizontal dispersion of the MP-T65RT. An astute observer of these graphs will notice something remarkable that occurs as we get away from the on-axis angle: the responses actually become very flat. Let’s individually separate some of these curves so it’s easier to see this effect:
The above graph is a number of some of the individual responses of angles of the MP-T65RT. The number above each curve on the far left denotes the angle degree of the response. The on-axis response is fairly uneven, and it remains that way out to 30-degrees. We can see it is leveling out a bit at 45-degrees, and at 55-degrees the response reaches a very good level of neutrality. This is nearly an absurd situation; many speakers will have a flattish on-axis response that becomes irregular as we move away from the on-axis angle, but with the MP-T65RT speaker, the reverse occurs! The take-away from this is that the MP-T65RT is capable of producing a very neutral tonal balance, but it happens at an angle way off the front axis of the speaker. To give you an idea of the kind of angle this happens at, we provide the diagram to the right. The MP-T65RT is a very wide-dispersion speaker that has a great off-axis response but a not-so-linear response around the front axis. Now let’s look at the width and shape of this dispersion pattern:
The above graph shows the same information that the preceding graphs do but depict it
in a way that can offer new insight regarding these speakers’ behavior. Instead of using individual raised lines to illustrate amplitude, these polar maps use color to portray amplitude and this allows the use of a purely angle/frequency axis perspective. The advantage of these graphs is that they can let us see broader trends of the speaker’s behavior more easily. Compared to many of the speakers reviewed here in the past, this is a very wide dispersion speaker. The acoustic energy produced by the MP-T65RT does not really subside until it reaches a very far angle off the front axis. In fact, the dispersion is so broad that this +/- 95-degree graph doesn’t fully capture the full nature of this speaker’s off-axis breadth. To get a greater perspective, let’s widen the angle of our polar map out to +/- 170-degrees:
Regular readers of our reviews will remember one other occasion where we thought such an extreme angle was necessary to really show a speaker’s behavior, and that was from the celebrated Philharmonic BMR Philharmonitor. What is astounding is the similarity in the horizontal directivity. This speaker, much like the BMR Philharmonitor, has a pretty strong response out to an 80-degree angle off the front axis. The directivity matching of the woofers to the tweeter here is excellent. Most speakers don’t have directivity this consistent and uniform regardless of pricing, but these speakers, which will likely be the lowest cost floor-standing speakers that this publication will ever review, performs superbly in this respect. It is bizarre to see such an excellent performance attribute in a speaker that is so cheap.
The above graph shows the MP-T65RT’s response behavior along its vertical axis where zero degrees is directly in front of the tweeter, negative degree values are below the tweeter, and positive degree values are above the tweeter. What can be seen here is that the response gets rough very quickly outside of a narrow angle on the vertical axis, so these speakers are best listened to with the tweeter at ear level. At too high or too low of an angle, all kinds of issues crop up as would be expected in a design of this nature. One significant problem here is that we can see a lot of high-frequency energy loss not too far of an angle above the tweeter, yet the tweeter on this floor-standing speaker is relatively low in height, so those users who do not address this issue will be left with a rather poor sound. This speaker should be listened to in a +/- 10-degree vertical angle of the tweeter. Ideally, the tweeter should be level with the listener’s ears. That is the case with almost all speakers, and that is especially the case with MTM speakers, and that is super-extra double especially the case with MTM speakers using a ribbon-type tweeter that has a very narrow vertical dispersion such as the design here. Possible solutions include setting the speakers on something that lifts their tweeter to an ear level height, angling the speakers back so that the tweeters’ path is level with listening position ears, or lowering the listening position so that listener’s ears are level with the tweeter. The natural height of this speaker is great for people who use beanbag chairs or other seating that places them lower to the floor than normal seating.
The above graphs show the MP-T65RT’s low-frequency responses that I captured using groundplane measurements (where the speaker and microphone are placed on the ground in a wide open area). The low-end of the MP-T65RT does start to roll-off at around 80 Hz, but it is a shallow slope that will still provide plenty of usable bass below the curve’s elbow frequency in any normal room due to room gain. The slope is too shallow to occur below port tuning. Many tower speakers use this kind of a low-end slope because having a flat response down to a low port tuning frequency can often lead to a bloated bass sound, since room gain can add a considerable amount of boost to the low-end response. The MP-T65RT doesn’t show any signs of having artificially elevated bass that can sometimes occur in cheap speakers as a way of creating a sense of deeper bass than is actually present. The low-frequency response is relatively flat from 80 Hz to past 400 Hz.
The above graphs show the electrical behavior of the MP-T65RT. What we see is a very easy electrical load for any amplifier. Monoprice rates the MP-T65RT as a 6 ohm speaker, but I would say that is a super-conservative spec. This is very much an 8-ohm speaker and doesn’t even quite have a 6-ohm minima. We can see from the low-end saddle that the port-tuning is around 40 Hz or perhaps just a bit below. We can see from the low-frequency mismatched impedance peaks that the port isn’t loading the woofer optimally, but that isn’t surprising given the design of the speaker. We do see that the planar tweeter has a beautifully steady impedance and phase response. There is evidence of cabinet resonance in the jaggedness of the impedance and phase curves around 200 to 300 Hz. Again, not surprising given the minimal construction of the cabinet. A few pieces of internal bracing or a thicker side-panel would greatly smooth out the curves there, but, of course, that would significantly add to the cost and weight of the speaker.
I measured the sensitivity at 88.2 dB for 2.83v at 1 meter. That is very close to Monoprice’s specification of 86 dB for 1 watt at 1 meter, and, if anything, it is a bit better. That is a fairly average sensitivity for a speaker of this type, which is good news, as a low sensitivity would cripple the dynamic range of this speaker given its somewhat low power-handling ability.
The main question posed by the MP-T65RT is how good can a floor-standing speaker be for $140 a pair? $140 would be a very low cost for bookshelf speakers let alone floor-standing speakers, yet Monoprice took a stab at this market segment---and with a speaker that uses a planar tweeter in an MTM orientation, no less. Their methods of cost-cutting are pretty obvious: the cabinetry is thin, the drivers are not exactly heavy-duty, and there isn’t really a crossover circuit used, just a couple high-pass filters. The penalty for this is that these don’t have the smoothest response on-axis, they don’t quite have the dynamic range that most tower speakers have, and I do hear some slight midrange congestion. And then there is the matter of the tweeter, which is mounted so low that it requires that the speaker be given some unique positioning adjustments to get its aim level with the listener’s ear. But all speaker design is a matter of trade-offs, and in a speaker as low cost as these, a better question to ask is what do they do right rather than focus on their faults.
The strengths of the MP-T65RT start with the far off-axis response, which is phenomenal for a low-cost speaker. If used to the listener’s advantage, that off-axis response can bestow a nicely-balanced sound. Another positive attribute is that the bass response is also unexpectedly even-keeled for a speaker of this cost. The electrical load of the speaker makes it totally benign for any audio amplifier out there. Its weight makes it a very easy speaker to deal with physically. And, of course, the price makes it affordable to a far greater number of people than many of the $2k/pair floor-standing speakers that we have been covering lately.
The MP-T65RTs might not be a perfect speaker, but I had a lot of fun with them. With an understanding of the MP-T65RT’s unique behavior, I could manipulate them to create different kinds of soundstages and tonalites. Angling them to face far outward from the listener creates a very large center image while angling them far inward really sharpens the center image, and because their far off-axis response is so flat, the tonality was still relatively neutral. Using such far off-axis angles as direct sound to the listening position would throw a lot of the acoustic energy off as into the reflected soundfield because the dispersion of the MP-T65RT was so wide. Or, to put that in another way, listening to very wide dispersion speakers at a far angle of their coverage meant that a greater quantity of its sound will end up as acoustic reflections. It had almost dipole-esque sound character when used in this manner. This is not a bad thing, in fact, it does make for a pleasant sound. I recommend angling them inward so that the listener is at a 50 to 60-degree angle to their on-axis direction for the best sound. As I said before, that is a strange speaker positioning, but they managed to produce a very good sound in this placement- shockingly good when considering the cost.
I would wholeheartedly recommend the Monoprice MP-T65RT speakers to audio enthusiasts on a tight budget. They are perfect for a college dorm for someone that wants good sound but won't freak out if their roommate puts a beer on top of the cabinet. What is more, I would recommend that those audio enthusiasts who are not at all tightly bound by money considerations try a set of MP-T65RTs just to see what kind of sound is possible from such a modest design. They don’t look like much, they feel cheap, but the sound that they produce is engaging, balanced, and articulate. The MP-T65RTs will not match the sound quality of a perfectly measuring high-end speaker, but, when set up correctly, I can say they do sound very good- implausibly good for the cost!
The Score Card
The scoring below is based on each piece of equipment doing the duty it is designed for. The numbers are weighed heavily with respect to the individual cost of each unit, thus giving a rating roughly equal to:
Performance × Price Factor/Value = Rating
Audioholics.com note: The ratings indicated below are based on subjective listening and objective testing of the product in question. The rating scale is based on performance/value ratio. If you notice better performing products in future reviews that have lower numbers in certain areas, be aware that the value factor is most likely the culprit. Other Audioholics reviewers may rate products solely based on performance, and each reviewer has his/her own system for ratings.
Audioholics Rating Scale
- — Excellent
- — Very Good
- — Good
- — Fair
- — Poor
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Recent Forum Posts:
Maybe a little weaker in the lower rumble, but that suits the living situation. I use them as desk speakers, planar tweeters are even about 8 degrees above the listening plane.
Many thanks for sharing a precious secret in the budget range!
kls0e, post: 1514219, member: 97163Do they sound good enough without upgrading the x overs . Or is that worth another $50-100 or what it cost ?? Yeah I read it . Better than the Andrew Jones pioneer Towers Im using FS 52???
Shady addresses these questions in his detailed review. My suggestion is to read it and make up your own mind. He puts enough facts on the table
Kingnoob, post: 1514051, member: 89775
Are these really way better then the price indicates??
Seem good for the price but are they worth it over other brands like insignia, infinity when on sale and others .. Polk ..
Shady addresses these questions in his detailed review. My suggestion is to read it and make up your own mind. He puts enough facts on the table :-)