Recos for entry level Bookshelf speaker $400-750 for 21yo nieces first system?

Looking for recommendations for a bookshelf speaker for a system I am buying my 21 yr old niece in DC. Will be used for all kinds of music, much from IPhone via Bluetooth or from Mac. Speaker should work on a shelf or tv stand so port forward or be closed. Amp will be NAD D3020 or similar small form of 30-40 w RMS.  Not necessarily audiophile but good musical sound. Have read about PBS, Elac, others. I live in HI so can't hear any of these. I appreciate any and all responses.

Peachtree Audio "deepblue2" Bluetooth speaker with 440watts of Class D amplification built in,stereo tweeters,stereo mid range drivers & a 6" bass driver in a sealed enclosure 9"high x 14"wide x 6.5"deep @16lbs..Automatic Digital EQ keeps tone naturally balanced regardless of room acoustics.Optical Digital Input & 3.5mm Input included...
I have owned PTA gear & they know how to make music so the sound should be very good.
REGA R1 / RS1. A New Budget Reference

"... The Rega R1 becomes my new budget reference speaker. In addition of its ability to get the fundamentals of music right, it adds clarity and resolution, and an ability to lay out a vivid and coherent 3-dimensional stereo image. In small room applications, what more could you want?..."

Read the whole review.

They are designed to be placed against a back wall ( they even have their own bespoke wall brackets) .... I had them in my office driven by NAD electronics and I currently still use them as surrounds in my HT mancave.

Highly recommended ......they are relatively easy to find new old stock or used (current RX1 model is past your budget) . Used R1 or RS1 kit comes up frequently including on AGON or or

Great sensitivity ~ 90db efficiency...easy to drive with smaller amp.

Depth ...236 mm
Weight ... 3.5 kg
Polk RTiA1 would be a nice entry level choice.  Small, easy to drive, and the powerport allows for placement close to/on wall.

Can be had new or via Polk's ebay direct site refurbished (with warranty) for less.

Great customer service.
Feel like building them? I have great plans for a pair that will get her into all sorts of music.
I agree completely with freediver's recommendation of the Peachtree Audio deepblue2. I bought one for my daughter to replace the first system I got her, a Pioneer Elite amp, DVD/CD player and Usher 520 speakers. She and her husband wanted a simpler setup because their toddler was beginning to twist knobs and bounce off speaker stands and they, like your niece, were listening mostly to music from their iphones and ipads.

The sound of the deepblue2 is remarkable, I haven't heard anything better at anywhere near the price. The engineering and ergonomics are great and the simplicity and versatility sound like a perfect match for someone like your niece. For a young person who might be changing locations for a few years the ability to pick it up and move it so easily is a real advantage, and its size makes it easy to fit in almost any living space.

I was so impressed with it that I recommended it to some friends who seldom used their conventional system because it was stashed away in a cabinet and, like many other people, the easy access to music on a phone or tablet meant they simply weren't playing CDs anymore. Best part is, the deepblue2 sounds much better than their old system.

My advice would be to spend the same amount of money you were planning on but spend it on a deepblue2 and an iPad. She'll thank you.

Dali Zensor
I second the RS1 recommendation... but it all depends on what sound you are after at the end...
I have the rega RS5 (RS1 + naturally blended 7" woofer without crossover) and they are all about mid-range... clear, detailed, articulate and uncolored mid-range, with a hint of well extended quality treble and some well defined bass notes. Sound stage width and depth are so so, but they image very very well and seem to play all music genres equally well.  So I suppose the  RS1's voice is similar minus the re-inforced bass band.
The one thing lacking in the regas is the upper-bass band, and consequently they can become boring and fatiguing, especially with movies.  Even after the addition of a sealed subwoofer, I am still missing the smoothness and warmth of the vandersteen 2 CE sig I used to have.

So a couple weeks ago, I ordered a pair of Wharfedale Denton based on look, size, and the reported warm character and good reviews.  I was disappointed at first as they sounded horribly muffled with over-emphasized upper-bass/lower-mids.  After some 70-80hrs of play while I was out, better decoupling from stands,  better placement, and a comparison with the regas, they got a lot better and I finally could find them some qualities...
Their FORTE:  wide, deep, enveloping sound stage, fair imaging, good detail in the bass/upper bass (drums and toms sound really good), surprising dynamics, smooth treble, play 60s recordings like champs, even better with classical, jazz.. They are great with movies, they actually make you feel that a sub is unnecessary.  They are full without becoming boomy unless they are close to walls and heavy furniture.  The quality of the cabinetry is remarkable.
Questionable however is how much they color/muffle voices. They seem to do well from low-mids all the way down, but unable to deal with overtones and complex harmonics above that.  I do not remember the Vandys muffling that much.
Compared to another warm speaker I used to have, the PSB image t5, the Dentons are clearly a step up.  They are more detailed, and dynamics and soundstage are way better.  The PSBs muffled sounds a lot more as I recall.
The Dentons are clearly the kind of speaker I want to have on hand, even though I would prefer more naturalness in the mid-range... maybe they are not fully broken-in; they seem to take a long time settling-in.  And at $500?  Can't have everything done right.

Just my recent experience... Hope you find a great bargain!
A pair of Zu cubes would be nice choice. Easily driven, compact, and capable of playing loudly (she is a 21yo). And, not too much money.
ELAC  B5/6 or Unify 5 depending on budget, PS Audio sprout for a very compact system making no apologies at triple the 1-1.5 k!
Silverline Audio Minuet
Own the PSB Image B4's and they are very impressive sounding small speakers. Fit and finish first class. Used under $200 pr. if you can find a pr. for sale. Rear ported.  Check out the Imagine Mini as well.
Anyone heard these ELAC B6s?
I went to the Newport Beach audio show and listened to a ton of very high end speakers.  Then I came to this one room with Silverline Audio Minuet Supreme speakers.  I was blown away how such a small speaker could sound so good.  I ended up buying my son a pair of the entry level speakers for $600.  He absolutely loves them and they are small.  I then went to the Elac room which were super highly touted.  I thought the Silverline speakers blew the Elac's away.  The Minuet Supreme had a little more richness in the sound.  You should at least do some research on these speakers.  For the size and cost, I think they are great.  I think they are $700.  They are out of California.  

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I have been watching for a used pair of the Silverline Minuets. If I was looking to spend $700 I would purchase a pair of the new 'plus' models. As willgolf suggested, research these.
just hooked up a pair of Quad 12L2 and they are awesome...look great too
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I own the Silverline Minuet Supremes and they are brilliant little hifi speakers...but they are not what I would recommend for a 21 year old girl. These would be perfect.
I also recommend the Rega RS-1's . After endless experimentation I found that the Rega's paired with a Dayens Ampino has remarkable synergy. The transparency and resolution of the pair made cable selection extremely  important.  I discovered that Kimber 8pr was up to the task. This combination is truly staggering within its power limitations.
If you have Best Buy in Hawaii, the B&W 685 S2 speakers sound fantastic for the price. 
Don't even think about passive speakers in that price range. The best you can do is a pair of JBL LSR305 + a Bluetooth DAC. Much much better sound for the money. Incredible dynamics that most 10k speakers can't reach. 
Thx for the responses. Will have to do more research before Xmas.
How about something really simple like the new Oppo Sonica Grand

No need for a separate receiver. Can be easily toted. Granted, I have no idea how it sounds, but it should be pretty good.

Vanatoo Transparent One. 

Amazon is selling the KEF X300A (which includes  a DAC + 2 amps for each speaker) for $599.98. It is pretty good for the desktop. I have had the KEF LS50 on the same desktop and that was definitely better but the cost of that system was close to $5000.

I bought the X300A and I am quite happy with the sound, especially for the price I paid.

BTW - There will be a new KEF ACTIVE LS50 available in Dec 2016 for $2200
I agree with the idea of going for active, or at least powered, speakers. Quality of sound for the money is very good when spending less than $1,000, especially when spending way less than $1,000. Then all that is required is an input (laptop, phone, ipad, etc.). Simple, convenient, good sound, portable.
For a 21yo girl I'd get the Audioengine HD6 and be done with it.  Includes built-in class A/B amps, DAC, Bluetooth receiver, analog input/output, and a remote.  Finishes are beautiful as opposed to most other competitors in this category, which I'd think she'd also appreciate.  All she needs is her phone and she's done.  I bought the B2 in walnut for my brother.  It looks and sounds great and he loves it, and the Bluetooth reception is excellent so I'd expect similar from HD6.  BTW, Dagogo reviewed them and greatly preferred them in direct comparison to Vanatoo.  You can read multiple reviews on their website.  30-day trial period as well.  Best of luck.