Reddit mentions of Alphasonik 6" Portable Rechargeable Battery Powered 600W PRO DJ Amplified Loud Speaker with 2 Wireless Microphones Echo Bluetooth USB SD Card AUX MP3 FM Radio PA System LED Ring Karaoke Tripod Stand

You'll need an amp to power the speaker, so that's something you should keep in mind.

Either that, or try to find some powered monitors for $600.

For example, two KRK Rokit 8's will achieve pretty deep bass at 45 Hz, and are self powered. They also fall within your budget. http://www.amazon.com/KRK-RP8G2-Powered-Studio-Monitor/dp/B001A6IGDG/ref=sr_1_3?ie=UTF8&qid=1376426453&sr=8-3&keywords=rokkit+krk

Or, you could buy the Audiosource AMP-100 50 wpc amp. $100 http://www.amazon.com/AudioSource-AMP-100-Stereo-Power-Amplifier/dp/B00026BQJ6/ref=sr_1_3?ie=UTF8&qid=1376426626&sr=8-3&keywords=amplifier

That would leave $500 for a pair of speakers. Since you're looking for party speakers with a lot of sound, you might just want to check out Cerwin Vega. They aren't really audiophile quality, but they should make lots of noise.

Two of these might do the trick for $400 total: http://www.amazon.com/Cerwin-Vega-VE-8-2-Way-Audio-Speaker/dp/B000EHYHJY/ref=sr_1_5?s=aht&srs=2529137011&ie=UTF8&qid=1376426810&sr=1-5&keywords=cerwin+vega

A pair of these JBL speakers might also do the trick for $400 for the pair: http://www.amazon.com/JBL-ES80BK-3-Way-Floorstanding-Speaker/dp/B00166ZFXO/ref=sr_1_4?s=aht&ie=UTF8&qid=1376426922&sr=1-4

Yeah the Dayton T652's at $120 pair are the only "towers" even close to this price point (review here http://affordablehomeaudio.com/2015/02/24/dayton-t652-review/). Everything else is at least twice that price (review links here https://www.reddit.com/r/AverageJoeAudiophile/comments/3vw7js/i_have_xxxxx_to_spend_what_should_i_buy_tower/). The Pioneer SP-FS52's are pretty good for $130 each. If you have a Fry's were you live they have these JBL ES80's http://www.frys.com/product/6181379 on sale right now for $117 each with Promo Code 3142552 (reviews here and elsewhere by googling http://www.amazon.com/dp/B00166ZFXO/). I have the big brother ES90's that I like quite a bit but they need lots of clean power.

Here is a list I made for a guy at work. Some of them are a bit out of this price range, but it gives you an idea. Also, remember, towers are sold individually, so you will need to double the price. This is also a tiny sample of what is available.

http://www.amazon.com/Klipsch-RF-82-II-Floorstanding-Speaker/dp/B0041GEZDM/ref=sr_1_2?s=electronics&ie=UTF8&qid=1393526632&sr=1-2&keywords=klipsch+speakers (my personal #1 pcik in this list)
http://www.amazon.com/KEF-KHT6000BL-Slender-Profile-Aluminum/dp/B000F189P2/ref=sr_1_2?s=aht&ie=UTF8&qid=1393526895&sr=1-2&keywords=kef+speakers

http://www.amazon.com/Focal-Chorus-726V-Floorstanding-Speaker/dp/B001L4ZZTA/ref=sr_1_8?s=aht&ie=UTF8&qid=1393527225&sr=1-8&keywords=focal+speakers

http://www.amazon.com/Klipsch-RF-52-Reference-Floorstanding-Loudspeaker/dp/B0041578BE/ref=sr_1_3?s=aht&ie=UTF8&qid=1393526674&sr=1-3&keywords=klipsch+speakers

http://www.amazon.com/Klipsch-RF-62-II-Floorstanding-Speaker/dp/B00415E7FE/ref=sr_1_13?s=aht&ie=UTF8&qid=1393526730&sr=1-13&keywords=klipsch+speakers

http://www.amazon.com/BIC-Amercia-Acoustech-Platinum-PL-89/dp/B001VIXH7I/ref=sr_1_18?s=aht&ie=UTF8&qid=1393526752&sr=1-18&keywords=klipsch+speakers

http://www.amazon.com/Focal-Chorus-714V-Floorstanding-Speaker/dp/B001ASBPO6/ref=sr_1_4?s=aht&ie=UTF8&qid=1393526792&sr=1-4&keywords=focal+speakers

http://www.amazon.com/Focal-Chorus-716V-Floorstanding-Speaker/dp/B001AN2E3W/ref=sr_1_9?s=aht&ie=UTF8&qid=1393526814&sr=1-9&keywords=focal+speakers

http://www.amazon.com/KEF-Q500B-Floorstanding-Loudspeaker-Single/dp/B00CE3LGAO/ref=sr_1_7?s=aht&ie=UTF8&qid=1393526934&sr=1-7&keywords=kef+speakers


If these are too pricey, here are some even cheaper ones that should be real good as well:
http://www.amazon.com/Pioneer-SP-FS51-LR-Floorstanding-Loudspeakers-Black/dp/B004H1M4NO/ref=sr_1_6?s=electronics&ie=UTF8&qid=1393527045&sr=1-6&keywords=pioneer+speakers+andrew+jones (this is the only pioneer model I would recomend)

http://www.amazon.com/JBL-ES80BK-3-Way-Floorstanding-Speaker/dp/B00166ZFXO/ref=sr_1_1?s=electronics&ie=UTF8&qid=1393527099&sr=1-1&keywords=jbl+es80

Here's a system for you, also from Amazon. It will accept analog inputs, coax/optical inputs, digital iPod inputs, and network connectivity (pandora/spotify). About the only think it won't do is decode HDMI audio.

Integrated Digital/Network Amplifier - $250 - Onkyo TX-8050

2X Floorstanding Speakers - $400 - JBL ES80BK

Subwoofer - $350 - Klipsch RW12D


http://www.amazon.com/Onkyo-TX-8050-Network-Stereo-Receiver/dp/B004UR486G/ref=sr_1_20?s=electronics&ie=UTF8&qid=1372773958&sr=1-20&keywords=integrated+amplifier

http://www.amazon.com/JBL-ES80BK-3-Way-Floorstanding-Speaker/dp/B00166ZFXO/ref=sr_1_10?ie=UTF8&qid=1372773553&sr=8-10&keywords=floorstanding+speaker

http://www.amazon.com/Klipsch-RW12D-12-inch-Reference-Subwoofer/dp/B000UVWIO0/ref=sr_1_19?s=electronics&ie=UTF8&qid=1372774285&sr=1-19&keywords=velodyne+subwoofer