The documentation here: https://www.raspberrypi.org/documentation/configuration/wireless/access-point.md
sets up a sorta old network configuration. Specifically hostapd is configured to run an 802.11g network that only runs at about 15Mbps on my device.
Reading through the hostapd docs, I wound up with a different configuration, that sets up an 802.11n network running on the 5GHz band. I believe the rpi can actually host an 802.11ac network but my Macbook is too old for that so I haven't been testing it.
The rest of the setup documented in the raspberrypi.org article is what I'm using; I've only tweaked the hostapd.conf.
If you want to find out what channels are supported on your device, you can use iwlist to list out the available channels, like this:
pi@raspberrypi[0] ~: iwlist wlan0 channel
wlan0 32 channels in total; available frequencies :
Channel 01 : 2.412 GHz
Channel 02 : 2.417 GHz
Channel 03 : 2.422 GHz
Channel 04 : 2.427 GHz
Channel 05 : 2.432 GHz
Channel 06 : 2.437 GHz
Channel 07 : 2.442 GHz
Channel 08 : 2.447 GHz
Channel 09 : 2.452 GHz
Channel 10 : 2.457 GHz
Channel 11 : 2.462 GHz
Channel 36 : 5.18 GHz
Channel 40 : 5.2 GHz
Channel 44 : 5.22 GHz
Channel 48 : 5.24 GHz
Channel 52 : 5.26 GHz
Channel 56 : 5.28 GHz
Channel 60 : 5.3 GHz
Channel 64 : 5.32 GHz
Channel 100 : 5.5 GHz
Channel 104 : 5.52 GHz
Channel 108 : 5.54 GHz
Channel 112 : 5.56 GHz
Channel 116 : 5.58 GHz
Channel 120 : 5.6 GHz
Channel 124 : 5.62 GHz
Channel 128 : 5.64 GHz
Channel 132 : 5.66 GHz
Channel 136 : 5.68 GHz
Channel 140 : 5.7 GHz
Channel 144 : 5.72 GHz
Channel 149 : 5.745 GHz